Ok, lets face it, cloning plants can be a chore, but is such an important part of our success. The EZ Clone Machines make this essential part of gardening a snap. Using an aeroponic application, the clones you put in the neoprene inserts get beautifully misted 24/7 and i have heard reports of VERY fast rooting clones in these machines (3-5 days?) I highly recommend the EZ Clone to anyone who wants to try and reduce root time and have cleaner cuttings in the end.
Aloha Friday gang! Seems like these months since I started this blog are just flying by at light speed. I personally have discovered and learned an enormous amount of incredible information on plants and horticulture, and I’m still excited to learn more…..With all that being said, I have been driven by an insatiable passion to learn some advanced science in horticulture. Here is a great video from Virginia Tech on molecular plant sciences. This is exactly the field I have been going towards. Check it out.
ALOHA gardeners, I actually planned on doing a post today on N-P-K, what it stands for, and how it effects your plants. I see so many indoor gardeners grow for years without even knowing what N-P-K is and why these chemicals encourage biological responses in plants. One of the most common questions we get here at the blog and in the stores is “can you please help demystify plant food science for me?” I would love to, I have included an extensive amount of links and vocabulary on the subject for all of you loyal PGS Blog readers.. ( Love you guys!)
N-P-K = Nitrogen, Phosphorous, and Potassium
N = Nitrogen 7-9-5
Nitrogen is the first major element responsible for the vegetative growth of plants above ground. With a good supply, plants grow sturdily and mature rapidly, with rich, dark green foliage.
P = Phosphorus 7-9-5
The second major element in plant nutrition, phosphorus is essential for healthy growth, strong roots, fruit and flower development, and greater resistance to disease.
K = Potassium (Potash) 7-9-5 The third major plant nutrient, potassium oxide is essential for the development of strong plants. It helps plants to resist diseases, protects them from the cold and protects during dry weather by preventing excessive water loss.
Fertilizers are chemical compounds applied to promote plant and fruit growth. Fertilizers are usually applied either through the soil (for uptake by plant roots) or by foliar feeding (for uptake through leaves).
Fertilizers can be placed into the categories of organic fertilizers (composed of decayed plant/animal matter), or inorganic fertilizers (composed of simple chemicals and minerals). Organic fertilizers are ‘naturally’ occurring compounds, such as peat, manufactured through natural processes (such as composting), or naturally occurring mineral deposits; inorganic fertilizers are manufactured through chemical processes (such as the Haber process, also using naturally occurring deposits, while chemically altering them (e.g. concentrated triple superphosphate.
Properly applied, organic fertilizers can improve the health and productivity of soil and plants, as they provide different essential nutrients to encourage plant growth. Organic nutrients increase the abundance of soil organisms by providing organic matter and micronutrients for organisms such as fungal mycorrhiza, which aid plants in absorbing nutrients. Chemical fertilizers may have long-term adverse impact on the organisms living in soil and a detrimental long term effect on soil productivity of the soil.
Fertilizers typically provide, in varying proportions, the three major plant nutrients: nitrogen, phosphorus, potassium known shorthand as N-P-K); the secondary plant nutrients (calcium, sulfur, magnesium) and sometimes trace elements (or micronutrients) with a role in plant or animal nutrition: boron, chlorine, manganese, iron, zinc, copper, molybdenum and (in some countries) selenium.
Both organic and inorganic fertilizers were called “manure”, derived from the French expression for manual (of or belonging to the hand) tillage, however, this term is currently restricted to organic manure. Though nitrogen is plentiful in the Earth’s atmosphere, relatively few plants engage in nitrogen fixation (conversion of atmospheric nitrogen to a plant-accessible form).
It is believed by some that ‘organic’ agricultural methods are more environmentally friendly and better maintain soil organic matter (SOM) levels. There are some scientific studies that support this position.
While manure, cinder and ironmaking slag have been used to improve crops for centuries, the use of fertilizers is arguably one of the great innovations of the Agricultural Revolution of the 19th Century.
In the 1730s, Viscount Charles Townshend (1674–1738) first studied the improving effects of the four crop rotation system that he had observed in use in Flanders. For this he gained the nickname of Turnip Townshend.
Chemist Justus von Liebig (1803–1883) contributed greatly to the advancement in the understanding of plant nutrition. His influential works first denounced the vitalist theory of humus, arguing first the importance of ammonia, and later promoting the importance of inorganic minerals to plant nutrition. Primarily Liebig’s work succeeded in exposition of questions for agricultural science to address over the next 50 years
In England, he attempted to implement his theories commercially through a fertilizer created by treating phosphate of lime in bone meal with sulfuric acid. Although it was much less expensive than the guano that was used at the time, it failed because it was not able to be properly absorbed by crops
At that time in England, Sir John Bennet Lawes (1814–1900) was experimenting with crops and manures at his farm at Harpenden and was able to produce a practical superphosphate in 1842 from the phosphates in rock and coprolites. Encouraged, he employed Sir Joseph Henry Gilbert, who had studied under Liebig at the University of Giessen, as director of research. To this day, the Rothamsted research station the pair founded still investigates the impact of inorganic and organic fertilizers on crop yields
In France, Jean Baptiste Boussingault (1802–1887) pointed out that the amount of nitrogen in various kinds of fertilizers is important.
Metallurgists Percy Gilchrist (1851–1935) and Sidney Gilchrist Thomas (1850–1885) invented the Thomas-Gilchrist converter, which enabled the use of high phosphorus acidic Continental ores for steelmaking. The dolomite lime lining of the converter turned in time into calcium phosphate, which could be used as fertilizer, known as Thomas-phosphate.
In the early decades of the 20th Century, the Nobel prize-winning chemists Carl Bosch of IG Farben and Fritz Haber developed the process that enabled nitrogen to be synthesised cheaply into ammonia, for subsequent oxidation into nitrates and nitrites.
In 1927 Erling Johnson developed an industrial method for producing nitrophosphate, also known as the Odda process after his Odda Smelteverk of Norway. The process involved acidifying phosphate rock (from Nauru and Banaba Islands in the southern Pacific Ocean) with nitric acid to produce phosphoric acid and calcium nitrate which, once neutralized, could be used as a nitrogen fertilizer
The Englishmen James Fison, Edward Packard, Thomas Hadfield and the Prentice brothers each founded companies in the early 19th century to create fertilizers from bone meal.
The developing sciences of chemistry and Paleontology, combined with the discovery of coprolites in commercial quantities in East Anglia, led Fisons and Packard to develop sulfuric acid and fertilizer plants at Bramford, and Snape, Suffolk in the 1850s to create superphosphates, which were shipped around the world from the port at Ipswich. By 1871 there were about 80 factories making superphosphateTemplate:Where?.
After World War I these businesses came under competitive pressure from naturally-produced guano, primarily found on the Pacific islands, as their extraction and distribution had become economically attractive.
The interwar period saw innovative competition from Imperial Chemical Industries who developed synthetic ammonium sulfate in 1923, Nitro-chalk in 1927, and a more concentrated and economical fertilizer called CCF based on ammonium phosphate in 1931. Competition was limited as ICI ensured it controlled most of the world’s ammonium sulfate supplies.
Other European and North American fertilizer companies developed their market share, forcing the English pioneer companies to merge, becoming Fisons, Packard, and Prentice Ltd. in 1929. Together they produced 85,000 tons of superphosphate/year in 1934 from their new factory and deep-water docks in Ipswich. By World War II they had acquired about 40 companies, including Hadfields in 1935, and two years later the large Anglo-Continental Guano Works, founded in 1917.
The post-war environment was characterized by much higher production levels as a result of the “Green Revolution” and new types of seed with increased nitrogen-absorbing potential, notably the high-response varieties of maize, wheat, and rice. This has accompanied the development of strong national competition, accusations of cartels and supply monopolies, and ultimately another wave of mergers and acquisitions. The original names no longer exist other than as holding companies or brand names: Fisons and ICI agrochemicals are part of today’s Yara International and AstraZeneca companies.
Major players in this market now include the Russian Uralkali fertilizer company Uralkali (listed on the London Stock Exchange), whose majority owner is Dmitry Rybolovlev, ranked by Forbes as 60th in the list of wealthiest people in 2008.
Naturally occurring inorganic fertilizers include Chilean sodium nitrate, mined rock phosphate, and limestone (to raise pH and a calcium source).
Fertilizers can be divided into macronutrients and micronutrients based on their concentrations in plant dry matter. There are six macronutrients: nitrogen, phosphorus, and potassium, often termed “primary macronutrients” because their availability is usually managed with NPK fertilizers, and the “secondary macronutrients” — calcium, magnesium, and sulfur — which are required in roughly similar quantities but whose availability is often managed as part of liming and manuring practices rather than fertilizers.
The macronutrients are consumed in larger quantities and normally present as a whole number or tenths of percentages in plant tissues (on a dry matter weight basis). There are many micronutrients, required in concentrations ranging from 5 to 100 parts per million (ppm) by mass. Plant micronutrients include iron (Fe), manganese (Mn), boron (B), copper (Cu), molybdenum (Mo), nickel (Ni), chlorine (Cl), and zinc (Zn).
Tennessee Valley Authority: “Results of Fertilizer” demonstration 1942.
Synthesized materials are also called artificial, and may be described as straight, where the product predominantly contains the three primary ingredients of nitrogen (N), phosphorus (P), and potassium (K), (known as N-P-K fertilizers or compound fertilizers when elements are mixed intentionally).
Such fertilizers are named according to the content of these three elements. For example, if nitrogen is the main element, the fertilizer is often described as a nitrogen fertilizer.
Regardless of the name, however, they are labeled according to the relative amounts of each of these three elements, by weight (i.e, mass fraction). The percent of nitrogen is reported directly. However, phosphorus is reported as the mass fraction of phosphorus pentoxide (P2O5), the anhydride of phosphoric acid, and potassium is reported as the mass fraction of potassium oxide (K2O), which is the anhydride of potassium hydroxide.
Fertilizer composition is expressed in this fashion for historical reasons in the way it was analyzed (conversion to ash for P and K mass fractions); this practice dates back to Justus von Liebig.
Since the N-P-K reporting basis just described does not give the actual fraction of the respective elements, some packaging also reports the elemental mass fractions. The UK fertilizer-labelling regulations [10] allow for additionally reporting the elemental mass fractions of phosphorous and potassium, rather than phosphoric acid and potassium hydroxide, but these must be listed in parentheses after the standard values. The regulations specify the factors for converting from the P2O5 and K2O values to the respective P and K elemental values as follows:
In phosphorous pentoxide, the element phosphorous constitutes 43.6% of the total mass of the compound. Thus, the official UK mass fraction (percentage) of elemental phosphorus is 43.6%. [P] = 0.436 x [P2O5]
Likewise, the mass fraction (percentage) of elemental potassium is 83%. [K] = 0.83 x [K2O]
Thus an 18−51−20 fertilizer contains, by weight, 18% elemental nitrogen (N) , 22% elemental phosphorus (P), and 16% elemental potassium (K).
(Note: The remaining 11% [100 - (18 + 51 + 20)] is known as ballast or filler and may or may not be valuable to the plants, depending on what is used as filler.)
| Country | Total N consumption(Mt pa) | Amount usedfor feed & pasture |
|---|---|---|
| China | 18.7 | 3.0 |
| USA | 9.1 | 4.7 |
| France | 2.5 | 1.3 |
| Germany | 2.0 | 1.2 |
| Brazil | 1.7 | 0.7 |
| Canada | 1.6 | 0.9 |
| Turkey | 1.5 | 0.3 |
| UK | 1.3 | 0.9 |
| Mexico | 1.3 | 0.3 |
| Spain | 1.2 | 0.5 |
| Argentina | 0.4 | 0.1 |
Nitrogen fertilizer is often synthesized using the Haber-Bosch process, which produces ammonia. This ammonia is then used to produce other compounds (notably anhydrous ammonium nitrate and urea) which can be applied to fields. These concentrated products may be used as fertilizer or diluted with water to form a concentrated liquid fertilizer, UAN. Ammonia can also be used in the Odda Process in combination with rock phosphate and potassium fertilizer to produce compound fertilizers.
The production of ammonia currently consumes about 5% of global natural gas consumption, which is somewhat under 2% of world energy production.
Natural gas is overwhelmingly used for the production of ammonia, but other energy sources, together with a hydrogen source, can be used for the production of nitrogen compounds suitable for fertilizers. The cost of natural gas makes up about 90% of the cost of producing ammonia. The price increases in natural gas in the past decade, along with other factors such as increasing demand, have contributed to an increase in fertilizer price
Nitrogen-based fertilizers are most commonly used to treat fields used for growing maize, followed by barley, sorghum, rapeseed, soyabean and sunflower[citation needed]. One study has shown that application of nitrogen fertilizer on off-season cover crops can increase the biomass of these crops, while having a beneficial effect on soil nitrogen levels for the cash crop planted during the summer season.
In general, agricultural fertilizers contain only 1 or 2 macronutrients. Agricultural fertilizers are intended to be applied infrequently and normally prior to or alongside seeding. Examples of agricultural fertilizers are granular triple superphosphate, potassium chloride, urea, and anhydrous ammonia. The commodity nature of fertilizer, combined with the high cost of shipping, may lead to use of locally available substitutes or materials from the closest and/or cheapest source, which may vary with factors such as the relative cost of transportation by rail, ship, or truck.
In other words, a particular nitrogen source may be very popular in one part of the country while another is very popular in another geographic region only due to factors unrelated to agronomic concerns.
Horticultural or specialty fertilizers, on the other hand, are formulated from many of the same compounds and some others to produce well-balanced fertilizers that also contain micronutrients. Some materials, such as ammonium nitrate, are used minimally in large scale production farming. The 18-51-20 example is a horticultural fertilizer formulated with high phosphorus to promote bloom development in ornamental flowers. Horticultural fertilizers may be water-soluble (instant-release) or relatively insoluble (controlled-release).
Controlled release fertilizers are also referred to as sustained-release or timed-release. Many controlled release fertilizers are intended to be applied approximately every 3–6 months, depending on watering, growth rates, and other conditions, whereas water-soluble fertilizers must be applied at least every 1–2 weeks and can be applied as often as every watering if sufficiently dilute.
Unlike agricultural fertilizers, horticultural fertilizers are marketed directly to consumers and become part of retail product distribution lines.
In many countries there is the public perception that inorganic fertilizers “poison the soil” and result in “low quality” produce However, there is very little (if any) scientific evidence to support these views. When used appropriately, inorganic fertilizers enhance plant growth, the accumulation of organic matter, and the biological activity of the soil, thus preventing overgrazing and soil erosion. Studies in Australia show ‘biodynamic’ or ‘organic farms are less productive and less sustainable than conventional farms that used inorganic fertilisers. The nutritional value of plants for human and animal consumption is typically improved when inorganic fertilizers are used appropriately.
Many inorganic fertilizers do not replace trace mineral elements in the soil which become gradually depleted by crops. This depletion has been linked to studies which have shown a marked fall (up to 75%) in the quantities of such minerals present in fruit and vegetables. However, a recent review of 55 reputable scientific studies concluded “there is no evidence of a difference in nutrient quality between organically and conventionally produced foodstuffs”
In Western Australia deficiencies of zinc, copper, manganese, iron and molybdenum were identified as limiting the growth of broad-acre crops and pastures in the 1940s and 1950s. Soils in Western Australia are very old, highly weathered and deficient in many of the major nutrients and trace elements. Since this time these trace elements are routinely added to inorganic fertilizers used in agriculture in this state.
There are concerns regarding arsenic, cadmium and uranium accumulating in fields treated with fertilizers. The phosphate minerals contain trace amounts of these elements and if no cleaning step is applied after mining the continuous use of phosphate fertilizers leads towards an accumulation of these elements in the soil. High levels of lead and cadium can also be found in many manures or sewage sludges.
Phosphate fertilizers replace inorganic arsenic naturally found in the soil, displacing the heavy metal and causing accumulation in runoff Eventually these heavy metals can build up to unacceptable levels and build up in produce.
Another problem with inorganic fertilizers is that they are now produced in ways which cannot be continued indefinitely. Potassium and phosphorus come from mines (or saline lakes such as the Dead Sea) and such resources are limited. Nitrogen sources are effectively unlimited (forming over 70% of atmospheric gases), however, nitrogen fertilizers are presently made using fossil fuels such as natural gas and coal, which are limited.
Innovative thermal depolymerization biofuel schemes are experimenting with the production of byproducts with 9% nitrogen fertilizer from organic waste.
A compost bin
Naturally occurring organic fertilizers include manure, worm castings, peat moss, seaweed, sewage and guano. Sewage sludge use in organic agricultural operations in the U.S. has been extremely limited and rare due to USDA prohibition of the practice (due to toxic metal accumulation, among other factors.
Cover crops are also grown to enrich soil as a green manure through nitrogen fixation from the atmosphere by bacterial nodules on roots; as well as phosphorus (through nutrient mobilization) content of soils.
Processed organic fertilizers from natural sources include compost (from green waste), bloodmeal and bone meal (from organic meat production facilities), and seaweed extracts (alginates and others).
There can be confusion as to the veracity of the term ‘organic’ when applied to agricultural systems and fertilizer. The problem is one of confusion of terminology between agricultural and chemical disciplines.
Minerals such as mined rock phosphate, sulfate of potash and limestone are also considered organic fertilizers, although they contain no organic (carbon) molecules. Some ambiguity in the usage of the term organic exists; however, it is simple to differentiate with a separation between the scientific and colloqial uses (as in velocity in common usage (Speed) and physics usage(Velocity)–see Velocity (disambiguation)).
Synthetic fertilizers, such as urea and urea formaldehyde, are organic in the sense of the organic chemistry definition of organic, can be supplied organically (agriculturally), but when manufactured as a pure chemical is not organic under organic certification standards
Naturally mined powdered limestone mined rock phosphate and sodium nitrate, are inorganic (in a chemical sense) in that they contain no carbon molecules, and are energetically-intensive to harvest, but are approved for organic agriculture in minimal amounts
The common thread that can be seen through these examples is that organic agriculture defines itself through minimal processing (e.g. via chemical energy such as petroleum—see Haber process), as well as being naturally-occurring (as is, or via natural biological processing such as the composting process).
However, by their nature, organic fertilizers provide increased physical and biological storage mechanisms to soils, mitigating risks of over-fertilization. Organic fertilizer nutrient content, solubility, and nutrient release rates are typically much lower than mineral (inorganic) fertilizers. One study found that over a 140-day period, after 7 leachings:
It is difficult to chemically distinguish between urea of biological origin and those produced synthetically. Like inorganic fertilisers, it is possible to over-apply organic fertilizers if does not measure and distribute the required amounts according to the recommended amounts for the plot of land in question. Release of the nutrients may happen quite suddenly depending on the type of organic fertiliser used.
Because of their dilute concentration of nutrients, transport and application costs are typically much greater for organic than inorganic fertilizers.
Organic fertilizers from treated sewage, composts and sources can be quiet variable from one batch to the next. Unless each batch is tested the amounts of nutrient applied are not precisely known.
High application rates of nitrogen fertilizers in order to maximize crop yields, combined with the high solubilities of these fertilizers leads to increased leaching of nitrates into groundwater The use of ammonium nitrate in inorganic fertilizers is particularly damaging, as plants absorb ammonium ions preferentially over nitrate ions, while excess nitrate ions which are not absorbed dissolve (by rain or irrigation) into groundwater. Nitrate levels above 10 mg/L (10 ppm) in groundwater can cause ‘blue baby syndrome‘ (acquired methemoglobinemia), leading to hypoxia (which can lead to coma and death if not treated)
Nitrogen-containing inorganic fertilizers in the form of nitrate and ammonium also cause soil acidification
Eventually, nitrate-enriched groundwater makes its way into lakes, bays and oceans where it accelerates the growth of algae, disrupts the normal functioning of water ecosystems, and kills fish in a process called eutrophication (which may cause water to become cloudy and/or discolored—green, yellow, brown, or red). About half of all the lakes in the United States are now eutrophic, while the number of oceanic dead zones near inhabited coastlines are increasing.
As of 2006, the application of nitrogen fertilizer is being increasingly controlled in Britain and the United States. If eutrophication can be reversed, it may take decades before the accumulated nitrates in groundwater can be broken down by natural processes.
Storage and application of some nitrogen fertilizers in some weather or soil conditions can cause emissions of the greenhouse gas nitrous oxide (N2O). Ammonia gas (NH3) may be emitted following application of ‘inorganic’ fertilizers, or manure/slurry. Besides supplying nitrogen, ammonia can also increase soil acidity (lower pH, or “souring”). Excessive nitrogen fertilizer applications can also lead to pest problems by increasing the birth rate, longevity and overall fitness of certain pests.
The concentration of up to 100 mg/kg of cadmium in phosphate minerals (for example, minerals from Nauru and the Christmas islands) increases the contamination of soil with cadmium, for example in New Zealand. Uranium is another example of a contaminant often found in phosphate fertilizers; also, radioactive Polonium-210 contained in phosphate fertilizers is absorbed by the roots of plants and stored in its tissues. Tobacco derived from plants fertilzed by rock phosphates contains Polonium-210 which emits alpha radiation estimated to cause about 11,700 lung cancer deaths each year worldwide.
For these reasons, it is recommended that knowledge of the nutrient content of the soil and nutrient requirements of the crop are carefully balanced with application of nutrients in inorganic fertilizer. This process is called nutrient budgeting. By careful monitoring of soil conditions, farmers can avoid wasting expensive fertilizers, and also avoid the potential costs of cleaning up any pollution created as a byproduct of their farming.
Fertilizer burn
Over-fertilization of a vital nutrient can be as detrimental as underfertilization. “Fertilizer burn” can occur when too much fertilizer is applied, resulting in a drying out of the roots and damage or even death of the plant. According to UC IPM, all organic fertilizers, and some specially-formulated inorganic fertilizers are classified as ’slow-release’ fertilizers, and therefore cannot cause nitrogen burn. Organic fertilizers are as likely to cause plant burn as inorganic fertilizers.
If excess nitrogen is present, some plants can exude the excess through their leaves in a process called guttation
Toxic fertilizers are recycled industrial waste that introduce several classes of toxic materials into farm land, garden soils, and water streams. The consumption levels of toxic fertilizer are increasing lately in the U.S. from citizens who are purchasing the wrong chemicals for their gardens as well as choosing the wrong company to purchase it from.
This is leading to major environmental problems due to the fact of toxic waste being processed and planted into our land and water. The most common toxic elements in this type of fertilizer are mercury, lead, and arsenic.
Between 1990-1995, 600 companies from 44 different states sent 270 million pounds of toxic waste to farms and fertilizer companies across the country
According to the United States Food and Drug Administration:
“Current information indicates that only a relatively small percentage of fertilizers is manufactured using industrial wastes as ingredients, and that hazardous wastes are used as ingredients in only a small portion of waste-derived fertilizers.”
“[the] EPA has continually encouraged the beneficial reuse and recycling of industrial wastes.”
Steel industry wastes, recycled into fertilizers for their high levels of zinc (essential to plant growth), wastes can include the following toxic metals:
Dioxins, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) have been detected in fertilizers and soil amendments
| “ | We throw away nutrients for our plants in underground sewage systems. We do this in such a way that pollutes underground water tables. Then we buy manufactured “nutrients” for our plants which aren’t as good as what we threw away. This is modern day wastewater “technology”. Michael Reynolds – Earthship Vol.2: Systems and Components |
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The growth of the world’s population to its current figure has only been possible through intensification of agriculture associated with the use of fertilizers.There is an impact on the sustainable consumption of other global resources as a consequence.
The use of fertilizers on a global scale emits significant quantities of greenhouse gas into the atmosphere. Emissions come about through the use of:
By changing processes and procedures, it is possible to mitigate some, but not all, of these effects on anthropogenic climate change.
The nitrogen-rich compounds found in fertilizer run-off is the primary cause of a serious depletion of oxygen in many parts of the ocean, especially in coastal zones; the resulting lack of dissolved oxygen is greatly reducing the ability of these areas to sustain oceanic fauna. Anoxic respiration by bacteria in the eutrophicated marine zones also releases nitrous oxide to the atmosphere. Through the increasing use of nitrogen fertiliser, which is added at a rate of 120 million tons per year presently to the already existing amount of reactive nitrogen, nitrous oxide has become the third most important greenhouse gas after carbon dioxide and methane, with a global warming potential 296 times larger than an equal mass of carbon dioxide, while it also contributes to stratospheric ozone depletion.
The mining of phosphorus for fertiliser uses leads to the depletion of the global (fossil) phosphate resources. It is unclear whether peak phosphorus has already been passed or has yet to come.
Was that enough info for you? Hope this helped you on your journey to a perfect garden! 1-866-PGS-GROW
Mycorrhizae play an important role in plant nutrition. Because they are unseen, they are often disregarded when it comes to deciding upon a cause for decline in a particular planting. Just what are mycorrhizae and why are they so important in plant production?
The word “mycorrhiza” means fugal root. To be more specific, mycorrhizae are fungi that have a symbiotic relationship with the roots of many plants. The fungi which commonly form mycorrhizal relationships with plants are ubiquitous in the soil. Many mycorrhizal fungi are obligately symbiotic and therefore are unable to survive in nature for extended periods of time without their host. Because the relationship between the fungus and the plant is symbiotic, both members of the relationship obtain a benefit from each other. Neither the host plant nor the fungus suffer any ill effects as a result of the relationship. The fungus, because it does not photosynthesize, cannot fix its own carbon. Consequently, it receives all of its necessary carbohydrates from the host plant. In return, the mycorrhiza absorbs nutrients from the soil which are passed along to the plant.
In most situations, the roots of a plant occupy only 0.5% of the topsoil volume and even less of the subsoil. Because the hyphae of the mycorrhizal fungus is thinner than the plant’s roots, it is able to come into contact with more soil on a per-volume basis. The mycorrhizal fungi are made up of a root-like structure and posses a network of mycelium external to the tree roots that extends into the soil. This mycelium absorbs nutrients and translocates them back to the host plant. As a result, there is an increase in the absorption surface area of the roots.
There are some plant nutrients that move slowly in the soil and may appear to be unavailable to the plant. The result of this sluggish movement is a deficiency symptom in the plant. This is particularly important in the case of phosphorus. Most of the phosphorus in the soil is in an insoluble form. Insoluble phosphorus is unavailable to plant roots that do not have mycorrhizal associations. These same mycorrhizal roots also form associations with litterdecomposing organisms and thus are able to obtain nutrients from an otherwise unavailable source.
There are two main classes of mycorrhizae: ectomycorrhizae and endomycorrhizae. The ectomycorrhizae are also know as sheathing mycorhizae. They are found on many evergreen trees and shrubs. Deciduous trees are also colonized and include plants in the genera Fagus, Betula, Quercus, Tilia, Populus, Salix and Castanea. The fungus covers the ends of young roots and only penetrates the cell wall of the cortex; no further cellular penetration occurs. The ectomycorrhizal fungi belong to the class of fungi called Basidiomycetes. Basidiomycetes are fungi that commonly produce mushrooms as their fruiting structures. This explains the occurrence of mushrooms in the root zone beneath the dripline of a tree. Ectomycorrhizae not only absorb phosphate from the soil but they also are important in ammonium and zinc uptake as well. The fungi that form a symbiotic relationship with the plant are relatively host-specific. However, some fungal species may be more generalized and will colonize several species of plants. Ectomycorrhizal fungi are dispersed either by airborne spores or through the transfer of infected plant tissue.
Endomycorrhiza, on the other hand, invade the plant’s roots and develop entirely within the plant. Vesiculararbuscular endomycorrhiza (V-A type) are the type commonly found on deciduous trees as well as annual agronomic crops and other herbaceous plants. Unlike the ectomycorrhiza, the mycelium of the endomycorrhiza penetrates the root’s cortical cells. The hyphae grow inter and intracellularly within the root. In woody ornamentals, only the short roots are affected. V -A endomycorrhiza belong to the class of fungi called the Phycomycetes, or water molds. Other common fungi belonging to this class include Phytophthora, responsible for root and crown rot; and Pythium, which causes damping-off in seedlings. The fungus forms specialized absorptive organs called haustoria which are responsible for the uptake of zinc and phosphate. The spores of the fungus germinate in the rhizosphere – the area of soil directly adjacent to the root’s surface – and are dispersed through infected plant material in the soil. They are generally nonspecific as to the host required and therefore will infect any suitable plant species.
In addition to increasing the uptake of nutrients, mycorrhizae often provide some protection against soil-borne diseases. They may also increase a plant’s tolerance to adverse conditions. Drought, high temperatures, salinity, and acidity, or a build-up of toxic elements in the soil are some of the effects on host plants that mycorrhizae reduce. This aspect may be important to a tree’s survival in landscape plantings.
With all of the benefits afforded woody ornamentals by mycorrhizal relationships, one should consider the interaction of soil management practices with these beneficial fungi. Mycorrhizal deficiency may occur in soils that have been fumigated, areas where large amounts of topsoil have been removed, or in areas where trees have not been previously grown. The latter is particularly the case with evergreens and ectomycorrhiza which are more host-specific. Additions of nitrogen, phosphorus, or complete fertilizers will reduce the presence and activity of mycorrhiza. This effect is variable with the strain of fungus involved.
Mycorrhiza can play an important role in plant health. Although they are unseen, their effects can be remarkable, particularly in the case of their absence. The next time you are baffled by the results of a soil test which indicates adequate fertility in an area that clearly shows symptoms of deficiency, question whether the symbiotic relationship between these beneficial fungi and your plants might be out of balance.
– Karen Delahaut, University of Wisconsin – Madison
Photos from the Mycorrhiza Information Exchange Website’s Image Gallery.
Original Page Here
Ever considered trying hydroponics? Thought It might be too hard or complicated for you? This Ebb and Grow system is perfect for any novice or expert horticulturist. With big results and minimal maintenance, you can have a booming hydro garden today.
The versatile 12-site Ebb & Gro System allows different size and shape configurations to fit your exact growing needs. Simply connect the interchangeable two-gallon grow pots to the controller unit and connect the controller unit to the 55-gallon reservoir for easy set-up. This ebb and flow system floods and drains the planters several times a day. Ebb & Gro comes with necessary tubing, pumps, and built-in timer, and all components fit into the reservoir for convenient transportation and storage.
This Ebb & Gro System is sold as a complete unit only. The controller and an optional six-site Ebb & Gro expansion kit are available separately
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| Mesoseiulus longipes has a brownish coloration. |
Mites are amongst the smallest of all members of the Animal Kingdom. Although they are incredibly abundant we rarely see them because most are under 1 mm (1/25th inch) long; some are much smaller than that. Mites comprise a very large group; scientists guestimate that there may be as many as a million different types, but so far only about 50,000 have been identified and named; many of these are species that are important to humans in one way or another.
Mites are arthropods, meaning that they have a hardened outer skin and jointed appendages. Within the arthropods, they are distantly related to insects, but more closely related to critters such as spiders and scorpions, with which they form the group we call arachnids.
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A partially grown Amblyseius californicus |
Mites have very diverse biologies. Many live in the soil where they feed on microorganisms, fungi, or dead organic matter, or where they prey on other mites, small insects and even nematodes. Others occur in the water where they have similar diverse habits. Gardeners are familiar with those that feed on plants, such as the many species of spider mites or “red spiders”, as well as the gall mites such as those that make the various lumps, bumps, and felty patches on silver maple leaves. Many mites are parasitic on insects or higher animals such as birds, reptiles, and mammals. Ticks, including both the wood tick and deer tick, are types of mites, as is the critter that causes scabies. But mites also provide beneficial services. For example, they are very helpful in the degradation of dead organic matter and therefore play an important role in nutrient recycling. But the group of interest here are the mites that hunt down, kill, and eat various pests of our gardens, landscapes, and ornamental plants. These predatory species, even though they are very tiny and usually overlooked, occur in virtually every landscape and are incredibly important in the natural control and biological control of certain types of plant pests.
The most important group of mites that are predatory on plant-feeding mites is the family Phytoseiidae, with over 2200 known species around the world. There is no common name for this family of mites or any of its members – they are usually just referred to as phytoseiid (fy-toe-see-id) mites based on the scientific name of the family. Although they are sometimes called “predatory mites” this can be a bit misleading as there are many other families of mites that are also predatory.
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| Phytoseiulus persimilis female (larger and darker) and young. |
Almost all phytoseiid mites live on plants. They occur in virtually all plant habitats, but they tend to be more uniformly present in perennial (undisturbed) habitats rather than areas that are cultivated regularly. This is because their small size means they don’t move great distances very fast. In the home garden they are more likely to be seen on roses or apple trees instead of radish plants or marigolds, especially earlier in the growing season. They occur commonly in perennial agricultural commodities such as orchards, vineyards, and forests.
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| A young Amblyseius californicus feeding on an egg of twospotted spider mite. |
Like most mites, phytoseiids are very tiny, in the range of about ½ mm (1/50 of an inch – about the size of the period at the end of this sentence). Because of this, they feed on very small prey. Probably the most important prey of most species includes other types of mites. They readily feed on spider mites, gall mites, and other types of mites that are plant pests. But they also feed on tiny insects, insect eggs, and other tiny arthropods. Amongst insects, they feed on the young crawler stage of scale insects and young thrips, for example.
Phytoseiids are a natural and common component of all healthy gardens. They are helping in pest management throughout the growing season. But there are also ways we can help them do a better job for us. When we make conscious decisions to use the beneficial “natural enemies” of pests, we are practicing what is known as biological control. The following are three types of approaches for using predatory mites in the garden or landscape.
Hypoaspis miles is not a phytoseiid mite, but is a predator from a related family, the Laelapidae. Hypoaspis is an effective predator of the eggs and larvae of fungus gnats, which are often problems in organic soils used for greenhouse plants and house plants.
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| A fully grown adult Amblyseius californicus on a leaf vein. |
There are many companies that sell predatory mites. Shipments arrive in temperature-controlled containers and contents are guaranteed to arrive alive. To find sources of predatory mites, type “predator mite” into your internet search engine; several commercial sources should be listed.
In conclusion, tiny predatory mites occur in our gardens as well as virtually all plant habitats world-wide. They are effective predators of plant feeding mites and tiny pest insects. Although they do occur naturally in gardens, their benefits can be increased if we resist using broad spectrum insecticides until they are absolutely needed. For some pest situations, it may be worthwhile to purchase and release predatory mites.
Information on specific products is provided as a service and is not meant to endorse one product over similar products. Remember that pesticide labels are legal documents; any uses not specifically indicated on the label are illegal and may be harmful to people or the environment.
– Dan Mahr, University of Wisconsin – Madison, Department of Entomology
All photos by Merritt Singleton, University of Wisconsin – Madison, Dept. of Entomology
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Happy Aloha Friday growers! It’s been a product filled week here on the blog, I thought we would dim the lights in the room and watch a fun video. This video is a time lapse recording of cuttings rooting in water over a course of 5 days. When I saw this video, it reminded me of the magical wonder of asexual reproduction and how incredible it really is. When you really think about it, one humble plant can be turned into not just a million plants, but an infinite amount of perfect clones, that when applied to food production, could feed the entire world an infinite amount of times. What a truly remarkable metamorphosis plants can make!
Can Fans and Filters have quickly become industry standard. The CF group is continually pushing the bar up a notch with their innovative ventilation products. We just got some great new things from them. People have been asking for these changes and now they are available. 1-866-PGS-GROW
Compost teas are seriously popular these days, and for good reason, they work! However, many people come into our stores unsure as to how to brew and use compost teas. The Bountea compost tea brew kit is an awesome and easy way to start making your own tea and reaping the benefits of micro organisms and Alaskan Humisoil.
A Complete Premium Organic Compost Tea System * Winner of 9 World Records for Giant Vegetables * Grow stronger, healthier plants * Increase resistance to pests and diseases * Reduce the need for fertilizers, compost and watering Each Bountea Compost Tea Brew Kit contains: Living Alaska Humisoil to provide a rich compost starter filled with beneficial microorganisms — Bountea Bioactivator, to help those microorganisms flourish — Marine Mineral Magic M3 to supply plant nutrients, minerals and trace elements — Root Web, special species of mycorrhizae fungi to help transport nutrients to plant roots. The Bountea Compost Tea System greatly promotes healthy and sustainable soil ecology. This in turn allows plants to use all the nutrients available in the soil and grow stronger and healthier. Care for the soil — Care for the Earth 
Clonex is a high performance rooting compound. It is a tenacious gel which will remain in contact around the stem, sealing the cut tissue and supplying the hormones needed to promote root cell development, and vitamins to protect the delicate new root tissue.
The ultimate rooting compound – used by professionals and amateurs the world over. CLONEX is a bright, translucent gel. It is a high performance formulation of hormones, vitamins and mineral nutrients.
CLONEX is better because:
Ever wonder how much light that plant on the way outside of your room is getting? Ever noticed that some plants in your room bust out these huge blossoms right next to another plant that made little buds and was right under the light? That’s because all plants have an ideal level of light that they need for optimal growth. Using more light then needed will not make bigger yields or plants. A great way to start understanding what levels of light your plants like and/or need is to use a light meter. I have always used my hand to measure how much light shines on it when i place it under the lights. (real scientific huh?) It did give me a relatively good indication of how much light each plant was getting but when I started using a light meter, I realized how much more defined and accurate I could be. It’s been fun and insightful to experiment with light placement, angles, heights, and different kinds of reflectors to see what gave me the biggest reading on the light meter. I will post at another time my results, but til then I strongly encourage you to buy a light meter yourself and start creating your own prosperous reality.
Photosynthesis & Plant Growth depend on the sun or specially designed lighting systems. But of that light reaching the plant, only specific types of energy (in the lighting spectrum) drive the photosynthesis process. Since light is the most important single factor affecting your plants’ life cycles, quality light meters are an essential tool in determining accurately if your crop is receiving the maximum light needed for healthy growth. A light meter allows commercial growers an accurate means of adapting to their plants’ needs as the light conditions change during a full growing season. * Identify best light level of healthy plants * Easy to use hand-held design * Get precise reading with two scales * Includes instructions and “Consumer’s Guide to Light Gardening” brochure * Lifetime silicon sensor – no batteries required * Read up to 5000 footcandles of sun, high intensity or fluorescent light * Exclusive “Zero” calibration feature – accurate to 2% * Full two year warranty – the longest in the industry
Recently a nice guy came into the offices here and had a dvd he made of a video from his garden with some bugs he couldn’t identify. He was having tremendous trouble getting rid of the bugs and they we causing considerable, visible damage to his plants. Upon inspection, I realized he had Thrips, and told him. He says I thought they had wings”. Well they do, but they also have a larval stage of development, the wings on adults tend to be fringed and not completely operable. I am a huge proponent of Neem oil, and have used it religiously for years. I tried a few Neem variations on these Thrips and saw absolutely no results. 
This prompted me to do a little more research and I found some great data on the subject. First of all, Thrips are among the most pesticide resistant insects around. They are very hardy and have a very sophisticated network of communication. They multiply quickly and actually cut holes into the leaf and insert either an egg, or an enzyme that starts to digest the plant cells, and prepares them for easier assimilation. This is what causes that silvery leaf film.
Silvery Leaf Film Left From Thrips Enzyme
They also secrete scents from there anal glands that tell other Thrips where plants cells that are primed for eating are located. I have seen so many great gardens turn into diseased and damaged gardens quickly from a round of Thrips. They are vectors for viruses, more then any other garden pest! This is not something that should be neglected, yes your crop can still go off with Thrips, but they will make your yield suffer, dramatically. Once established, flying adults start to really do damage as they can fly around the whole garden and find the most tender and young shoots to feast upon. So after hearing from so many different people about their Thrip problems, having suffered a poor crop myself from it, I made a pledge to understand how to defeat them. Fear not people, I have made strides and have discovered a few powerful solutions.
Thrips Enzyme Injected Into Leaf and Digesting Cells
Of Course prevention is the ultimate cure…. If you go to a friends garden and he has Thrips ( your fucked – JK ), take steps to avoid contaminating your garden too, by changing your clothes and even taking a shower before entering your garden. Have a weekly maintenance plan that involves inspection and hand wipe removal of eggs, debris, larvae, adults and nymphs. Stay vigilant and active in your pursuit to identify where Thrips are hiding ( usually in the knuckle of the leaf ) – Summer can really bump up the number of Thrips in your area outside and they can catch a ride into your room in a myriad of ways. Ducting, Pets, Cracks, Clothing, Friends, Other Plants, etc… All these things should be considered when it comes to addressing these foul pests.
Here are some really great images I found online to help you identify this enemy! Not to be taken lightly, these bugs left alone, will reduce your yield and quality in one fail swoop. Don’t let this sophisticated enemy win… Arm yourself with this knowledge and get in there on the front line. (under the leaf, and in the cracks of stems) All of this is leading to my grand solution for Thrips…………..
Green Light Lawn and Garden Spray Concentrate with SPINOSAD. This is an OMRI Listed organic pest solution that contains an interesting bacteria called Spinosad. This compound is unlike any other pesticide ever. It has less of an impact on your other beneficial micro organisms and insects. ( such as nematodes and ladybugs ) and packs a serious punch on Thrips. Its “Caution” signal word indicates a reduced risk to applicators and workers. There are no specific worker protection requirements, even though applicators and handlers should wear a long-sleeved shirt, long pants, shoes and socks. All reports and my personal experience with this product are positive, particularly in respect to Thrips. After trying pyrethrins, fatty acid soaps, and neem oil solutions, and seeing no results, I realized I needed to try something else. ( I felt like these bastards where immune to everything) after one application of Spinosad, I have seen NO Thrips in my garden. The re-application rate is often enough to really knock the Thrips down and break the reproduction cycle. Best part is it’s ORGANIC
Don’t let this enemy get the most of you, stop letting Thrips eat out on your account at the RITZ CARLTON of buffets, YOUR GARDEN. Think about how much your crop is worth to you, and then think about how many tanks of gas or meals out these insects are literally taking from you!! FIGHT BACK, TAKE BACK YOUR ROOM! We have Spinosad at all our stores and online! 1-866-PGS-GROW 
After designing and building so many large commercial hydroponic systems throughout the world, it’s often a nice change of pace to create small hobby systems for home use. They’re fun to make and even more fun to use and observe. And of course, when filled with a variety of plants, a home hydroponic garden can spruce up any patio, solarium or living room. By far the best aspect of a home system in my opinion is convenience. Even in the dead of winter you can have fresh flowers all the time if you wish and no more running out to the store because you forgot a green pepper, one of the most important ingredients in that recipe you wanted to try tonight.
Over the years I have made a number of home hydroponic systems from materials I could find nearby, whether they be PVC tubes from the hardware store or plastic bags from the supermarket. My whole philosophy of hydroponics is to keep it simple, and this is even more important for home units. Nobody wants to come home from a long day at work to battle with their garden.
The Basics
If you understand how hydroponic systems work–which is not difficult–you should have no problem building and maintaining the home unit I describe below. Most hydroponic systems employ some type of media, like rockwool, expanded clay pellets or perlite, to support plants and hold nutrient solution in their root zone between watering cycles. In medialess systems (often referred to as “water culture”), a continuous supply of nutrients is provided to plant roots either in a fine mist (aeroponics) or flow, in which the root tips hang (Nutrient Film or Flow Technique). A combination system, called aerohydroponics, employs both the flow of nutrient and the fine mist for the best of both worlds. Another water culture system is the float system, which many of you have probably read about in other articles I’ve written for The Growing EDGE. This type of system works by placing plants in a foam board so their roots hang through it, and floating the board so their roots hang through it, and floating the board on the surface of the nutrient solution in a tray or pan. There’s no doubt that all of these systems work very well, but they do have some drawbacks for home applications.
For example, medialess systems that rely on the continuous flow or misting of nutrient solution–like aeroponics, NFT and aero-hydroponics–are more at risk from power outages and mechanical failures. Because they have no media to hold solution in the root zone, if a blackout occurs, roots are subject to drying out, which can happen very quickly and destroy your entire crop. The float system is not very practical for home use as it limits your growing choices to short term crops like lettuce since the roots are submerged in the nutrient at all times. The roots of longer term crops would start to break down in these conditions after a while. Also, the nutrient solution is very accessible to pets and children, which could be harmful to them.
Top-Feed Tray System
The system I prefer, and have on my own patio, is a recirculating tray unit filled with perlite. In this top-feed drip system, a two-inch layer of perlite serves as the growing media and nutrient is dripped in at one end and gravity-fed to a drain at the other end, which directs it back to the tank for recirculation The system requires very little attention and if the power goes off, a dripper clogs or a pump failure occurs, you have 12 to 18 hours to correct the situation. And because it works with a medium, the nutrient is buffered, which helps minimize errors in mixing calculations if you accidentally knock the pH off balance a little.
I first set this system up for a neighbor of mine who owns a local French restaurant. When my son saw the unit producing beautiful, thriving herbs in her house, he insisted we have one of our own, so within a week, we built a double unit and planted it with herbs, tomatoes, lettuce, peppers, flowers and any other seeds my son could get his hands on. That was three years ago. Today the system is still on our patio putting forth an abundance of fresh food and flowers.
Parts and Assembly
The parts for my home unit were all bought locally and are easy to replace if necessary. The two roof pans used for the growing beds are 12 inches wide, two inches deep and 6 feet long. Often used for construction projects, roof pans like these are available in most hardware stores. They are aluminum with an enamel coating, which is excellent because they are so durable. However, if you cannot find pans like these, it’s very easy to build similar beds from wood. All you have to do to prepare them for hydroponics is line them with double layer, six-millimeter polyethelene to make them waterproof.
For actual growing system, you’ll also need a small Maxi-Jet aquarium pump and either a recycling container with a lid or a 10-gallon Rubbermaid® storage bin for the nutrient tank. We’ll get to the irrigation supplies a little later.
To make the stand, you can use regular Schedule 40 three-quarter-inch PVC pipe, and fittings to connect the pipes together. It is essential for you to create a one-inch slope from one end of the stand to the other for nutrient drainage to occur. The diagram below shows the construction of the stand and its slope for a single bed. You’ll want to build your stand according to how big your growing area is. My home system, as you can see in the photos, is a double-long bed. To start off, you may want to just make a system with only one growing bed (roof pan).
Once the stand is ready, the trays just get pop-riveted to it, using a silicone sealant to caulk around the rivets. Then you drill two half-inch holes in the lower end of each sloped tray and screw a male half-inch PVC adapter into each; don’t forget to caulk around them with silicone to protect against leaks. Connect equal lengths of half-inch PVC pipe to each adapter, using elbows and a T-fitting to create a cross-bar between the two that will join them into a single drain line to the nutrient tank, which should be situated directly beneath the drainage holes. Refer to the diagram below for a better idea of how this should look. In the systems I built, I fitted each of the drain holes in the end of the growing beds with a three-inch tube of window screening to prevent perlite from entering the nutrient tank.
Now for the most important part, the nutrient delivery system. You’ll notice that the photo of my home unit differs a little from the diagram. I used PVC piping for my irrigation line and it doesn’t go all the way around the growing beds. You can do that, or you can follow the diagram, using either half-inch PVC pipe or standard half-inch irrigation line, which can be bought at any do-it-yourself home store or K-Mart®.
To follow the diagram, lead half-inch irrigation tubing from the pump in the nutrient tank up and around the growing beds to the high end of the tray. Obviously the tubing won’t just stay like this and it will bend as you curve it around the beds, so you’ll need to cut it into sections, connecting them with elbow-fittings around each corner. In total you’ll have to cut the line into five different sections, connecting them with four elbows. You’ll need a yard stick or measuring tape to determine where you’ll need to make your cuts and connections. Precise measurements are dependent on the height of your stand and square footage of your growing bed. The end of the irrigation line will need to be closed off as well. If you use PVC pipe, end pieces can be bought to close off the tubes. With irrigation line, you can use a figure eight end adapter to do this. All it is a piece of plastic shaped like a figure-eight; you stick the end of the tubing into one of the loops in the figure eight, bend it and stick it through the other loop. The bend closes off the line. One point that should be made: if you use irrigation line, it probably won’t stay stiff above or along the outside of the growing bed as pictured in the diagram, so you may have to afix it somehow to the edges of the tray or just lay it along the surface of the perlite around the edge of the bed.
Finally, at the opposite end of the bed from the nutrient tank, drill a couple of holes into the irrigation line with an 1/8-inch drill bit or irrigation line key punch. Once you pop the drippers or spaghetti tubing into those holes, your feed lines are ready.
Almost Done
At this stage, you’re ready to test the unit. Prepare the perlite by flushing all the dust out. Don’t forget to wear a mask when you do this; the dust is bad for your lungs. When it’s ready, pour it into the system, smoothing it out about a half-inch from the tip of the tray. Fill your nutrient tank with water and plug in the pump. If there is too much pressure from the pump, make a small hole in the pipe near the pump. When everything is running okay, add nutrient and plant!
Testing the EC and pH of your nutrient solution should be done daily.
The thing I like most about this unit is that it gives me a 12-square-foot growing area that can easily be doubled without even switching to a larger nutrient tank. With 24 square feet of growing area, you should have enough produce to feed a family of four. Another great feature is that it is very easy to maintain, and if you go away on vacation, you can simply add a small float valve and line to a water hose to keep the tank filled. I have left our unit for over three weeks with this method, and other than our herbs being overgrown and little yellowish, everything survived, and within a few days of my return all was back to normal.
Have fun with your new hydroponic unit, and remember to spread the word that hydroponics works and grows!
Gordon Creaser is a regular columnist for The Growing EDGE and professional hydroponics consultant.
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Whether your setting up your first grow room, or your 50th, SecretJardin Darkrooms are perfect, ready to go grow rooms. Sometimes you may not want to do an elaborate build inside your house. Perhaps your renting and you don’t want to damage the walls and ceilings. Maybe you want to isolate strains and run controlled tests. There are so many reasons why a grower would need a Darkroom. Another amazing application is for nursery and vegetative growth in a spare closet or room in your house while flowering in another Darkroom, keeping a never ending run of plants ready to go into flowering. We saw these guys at the Indoor Gardening Expo and we all got pretty excited to see the new Mammoth and Titanium Darkrooms. Quality is written all over these products. With all the small details a grower needs, holes for ventilation and wires, super strong titanium skeleton, HUGE water tight floor pan, and incredibly durable and reflective inner walls. The whole concept of a Darkroom inside of a room in your house is perfect. Keep your garden(s) compartmentalized and controlled with SecretJardin Darkrooms. The best feature of all is that if you need to break down quickly for any reason, all the darkrooms come with cases that you can pack your grow room into easily and put it in your closet or whatever till you need it… We carry a full line of sizes and variations give us a call and light it up! 1-866-PGS-GROW
SecretJardin Darkrooms @ The Indoor Gardening Expo
Ok, well Im taking the liberty of calling today, “Aloha Tuesday” – Yes any day can be an Aloha day, and after the Monday we had around here, I am mandating a morale booster video to go with “Aloha Tuesdays” post here at the Definitive Growers Blog. I’m so loving this, please watch these brilliant indoor gardening tips from Christopher Walken. “Gotta know where these plants stand”
Sunlight Supply is an awesome company! Not only do they offer a variety of super high tech, high end reflectors, they also have a very low tech reflector that is making waves around here. People are seeing huge yields with this Adjust A Wing reflector series from Sunlight Supply. We have a full range of sizes available and are getting rave reviews from our clients. Try a couple and see for yourself! 1-866-PGS-GROW.
ALOHA Friday gang!!! I have another super exciting video for us today. (Don’t I always?)
This is so fascinating! We all have heard about how common house plants can help clean and purify our environments. Here is a scientific look at that concept, going into detail on the types of plants that are the most beneficial and why they clean the air around us, and better yet, how it positively affects us.
Researcher Kamal Meattle shows how an arrangement of three common houseplants, used in specific spots in a home or office building, can result in measurably cleaner indoor air.
Kamal Meattle has a vision to reshape commercial building in India using principles of green architecture and sustainable upkeep (including an air-cleaning system that involves massive banks of plants instead of massive banks of HVAC equipment). He started the Paharpur Business Centre and Software Technology Incubator Park (PBC-STIP), in New Delhi, in 1990 to provide “instant office” space to technology companies. PBC-STIP’s website publishes its air quality index every day, and tracks its compliance to the 10 principles of the UN Global Compact, a corporate-citizenship initiative.
Meattle has long been a environmental activist in India. In the 1980s he helped India’s apple industry develop less-wasteful packaging to help save acres of trees. He then began a campaign to help India’s millions of scooter drivers use less oil. His next plan is to develop a larger version of PBC-STIP, making a green office accessible to more businesses in New Delhi and serving as an example of low-cost, low-energy office life.
“He has spent a great deal of time in India and abroad convincing corporate leaders, diplomats, energy ministers, and other government officials that his ideas about sustainability, individual responsibility, and respect for the environment can ensure a healthier future for everyone. ‘Either you are overwhelmed by the fact that there are so many problems and so many people,’ says Meattle, ‘or you find solutions to help in any way you can.’”
Kamal Meattle in MIT’s Technology Review
Summer is upon us. And most indoor gardeners, unlike their outdoor counterparts, are hoping for a poor one. A hot summer usually means hot growrooms. High temperatures in your growroom can devastate the quality and quantity of your crop. Plants ‘survive’ rather than thrive. Some growers even shut down their operations all together preferring to reserve their energies for later in the year. But there are many ways to counteract rising temperatures, as Everest Fernandez explains:
48 degrees Celsius. It’s roughly the temperature of my oven when I warm some plates. You can also experience this heat by visiting Delhi in May. Unbelievably, it was also the maximum temperature recorded in my friend’s growroom a few years ago. Despite a generous watering the day before, the vast majority of his plants had wilted, most likely cursing him as they shrivelled. Featherlight pots, frazzled, crisp leaves… it was all a very sorry sight. Tragically they were six weeks into flowering and it all ended right there and then. The yield was poor. And the quality was … embarrassing.
What had gone wrong? Well, everything really. It was the first time my friend had ever grown in a loft and he didn’t fully appreciate that un-insulated roof space is particularly susceptible to extremes in temperature. i.e. in the winter it can get very cold, and in the summer it can become like a furnace. Whereas I was smugly enjoying fairly uniform temperatures all year round in my cellar.
My friend’s attic set-up was overly simplistic – mainly due to his resistance against parting with much cash. Fifty or so plants in ten litre pots were relying on on “natural ventilation”, as he put it, from the eaves. Yes, that’s right, just a few oscillating fans were shifting the air around with no artificially created inflowing air and no extraction! Now add 3,200 watts of light to this monstrous equation, a Great British heatwave, mix liberally with inexperience and downright stupidity, and the result? I could actually smell the plants cooking when I opened the loft hatch…
Ok, enough extreme examples! But what does ‘too hot’ actually mean in botanical terms?
Everest’s Hot Grow Room Rule Of Thumb
If it’s uncomfortable for you to be in your growroom, then it’s highly likely that it’s uncomfortable for your plants too. So, if you find yourself ripping off you t-shirt (grrrr!) after a few minutes of plant-tending and drying your sweaty pits infront of a fan then let this be a clear signal to you that you have a heat problem!
When temperatures are high more water (in the medium) is lost to evaporation. If the nutrients are then too concentrated in the drying medium the roots will burn and the leaves droop and may be lost altogether. When temperatures rise above a certain level plants effectively shut down photosynthesis and just concentrate on surviving, rather than focusing on growth or flower development. Damage will not be obvious but the delay to production will be. High temperatures can also cause some plants to ‘stretch’ and become leggy. Deadly root diseases like pythium thrive in high temperatures.
Everest’s Ideal Growroom Temperature
I’m happiest when the maximum temperature in my growroom is around 25 to 27 degrees Celsius. 28-32 degrees celsius is tolerated but is not ideal. I measure this temperature by placing a probe in a shaded spot in amongst the plants. I like my minimum temperature to be around 15-18 degrees Celsius.
Heat Problems And Growroom Solutions.
Ok so we’ve established excess heat as our enemy. If you grow plants for essential oils then you should be particularly vigilant against high temperatures – ideally you should be looking for a 10 degrees Celcius difference between your daytime and nightime temperatures.
Ambient Temperature (i.e. the actual temperature outside)
It may sound a bit obvious, but it’s worth pointing out: If it’s hot outside it’s going to be hot inside. Make sure your lights come on at night when outside temperatures are cooler. Consider a shorter cycle (eg. 10 hours on, 14 hours off) to speed things up a bit. Keep inflow and extractors on 24/7 – plants are still busy developing at night and enjoy fresh air during this time too. Try to take air from a cool room in the house or an outside vent in a shady area. If your house is too hot for plants, try reducing the thermostat temperature of your central heating. You will get used to the lower temperature in your house very quickly and your health may improve. Your wealth certainly will as your electricity or gas bill drops. The ultimate solution? Seal your growroom and invest in an air-conditioning unit and CO2 emitter. We’ll be looking at AC units, evaporative coolers, ultrasonic humidifiers, and reservoir chillers in the next issue.
Heat from bulbs
H.I.D. lights produce a lot of heat. And as bulbs become older they produce less light and more heat! So there we have two very good reasons to change them regularly! Air-cooled lights allow you to isolate the hot air around the bulb and vent it outside of your growroom! Water-cooled lights have been offered in the past, the dangers are so obvious that we don’t need to mention them. Protect your rootzone by covering pots or tanks with white or silver reflective corriboard or plastic sheet to reflect away the direct heat from the lamps. The roots are particularly sensitiveve to heat. Leave some space around the stem to allow it to breathe.
Insufficient air transfer
It’s no good just moving the air in your growroom around with an oscillating fan. In the absence of an A/C unit, you are going to need to provide fresh air for you plants to breathe. This also means you can replace hot air with cool, and so reduce the temperature in your growroom.
In order to create an effective inflow / extraction system you are going to need to know the volume of your growroom, and thus the amount of air you are trying to exchange.
Everest On Air Transfer
Check out our complete guide to growroom ventilation (based on energy rather than room volume.)
A simple rule of thumb is that you need 12 times the volume of your room in air moved every hour. If your actual room is much bigger than the area used for growing then imagine a comfortably-sized room around your plants and use that size in the calculations. For example:
height x length x width 2.3m height x 4m length x 3m width = 27.6m³ For room measurements in feet divide the ft³ by 35.3 to get m³
12 x 27.6m³ = 331.2m³ so the fan you select should have more than 331 m³ per hour of airflow.
If using a carbon filter multiply the number by 1.5 as some of the power of the fan is used in forcing air through the filter. Ducting should be as straight as possible to avoid reducing the airflow.
CO2 reduces the need for air-changes due to the plants being more resistant to heat and not losing so much water. The plants should still not be allowed to get above 30 degrees celsius. If the heat is not too bad 8 changes of air per hour will be enough.
The air you draw out of your growroom should be taken directly from around the H.I.D. bulbs and / or from the top of your growroom (as warm air rises).
In attics, consider investing in some vented roof tiles fitted. You can fit flexible ducting directly on to these and pump hot air directly out of your growroom to the outside world. Also, note that many modern houses are now built with ducting from bathrooms and cookers that leads straight into the loft and out through the roof. It’s possible to double up these precious routes to the outside world by fitting a ‘Y’ shaped adaptor that allows two ducts to share the same exit. But remember, don’t interfere with chimneys or ducting from boilers, gas fires or any other sources of carbon monoxide – mistakes can be fatal!
It’s important to balance the rate of “air in” with “air out”. When choosing your inflow fans and extractors, I think it’s best to ‘over-spec’ slightly and run them through a fan controller unit such as a Klimavator or Prima. Too much air passing through your growroom will have a drying effect on your plants. Whereas an imbalance of inflow and outflow can have strange effects too – I recall a pair of friends who spent most of their money on half a dozen standard 600 watt lights, blazing away in their attic. The high temperatures and swampy feel in the growroom indicated that they should have allocated more of their budget to more suitable inflow and extraction. They tried to fix the situation by pumping air from the downstairs kitchen (the coolest in the house) up into their attic through a huge ‘elephant trunk’ of ducting attached to a monster RVK 350 fan. They fired it up and the cool kitchen air dropped the temperature in their growroom by 10 degrees celsius in as many minutes. But, because of the inadequate extraction, the hot swampy attic air was simply pushed all the way downstairs back into the kitchen! This, of course, quickly rendered their efforts redundant.
If your growroom is well insulated it will be less affected by changes in ambient temperature. This is why cellar growers (insulated and cooled by moist mother earth!) enjoy such uniform temperatures (albeit often with higher humidity thrown in).
Opt for lights with remote ballasts – more or less the norm these days. Ballasts give off a surprising amount of heat. It’s worth packing these boxes of joy away for a number of reasons – not least, safety! You don’t want ballasts anywhere near your nutrient solution reservoir any more than you want water-cooled lights, for example! Invest in ballasts that have longer cables so you can stash them away from all the action.
Thanks to UrbanGarden Magazine for the Article- Original Page Here
Botany and Horticulture are blanket terms used to describe any plant oriented activity. I thought this would be a great time to talk about the differences and similarities. Horticulture is the study and activity of growing and caring for plants, and developing new species, hybrids, and techniques. Botany is the science of plants, identifying species, and making scientific correlations. These two academic disciplines are both wildly interesting. A Horticulturalist can tell you the best way to grow a certain type of flower in certain types of conditions, and a Botanist can identify what types of flowers and fauna are present around you outdoors, and why they grow there. As we take a close look at these definitions I encourage everyone to check these two links from Wiki on the two sciences. Botany on Wiki - Horticulture on Wiki – With all that being said, if we take a close look at what kind of science applies to us and the kind of gardening we do, I think its fair to say we are Horticulturists. Maintaining and perfecting the growth of our plants is the ultimate goal. I must admit that Botany remains an incredibly interesting part of it all too. Here is a quote from a Botanist – “I’m a botanist and everyone always asks me to help their house plants grow better when I tell them that, so I inform them that, “Horticulturists keep plants alive for a living, botanists kill plants for a living.”since we have huge collections of dried pressed plants called Herbariums for verifying species identifications.That’s a bit tongue in cheeck, and I try to be a bad botanist, keeping a pretty thriving garden going, but I’d definitely say that botanists look more at plants in their natural habitat and try to identify species and how they’re related, whereas horticulturists try to create new species and figure out how to grow plants in new habitats.
As this summer season blazes on, I personally had some major heat issues in my room. I could have avoided some serious damage with a simple controller from CAP. The High Temp Shutdown w/Delay, Model # HLC-3e. Basically this simple device constantly measures the tempurature of your room and will shut your lights off if the temp reaches a set level. This is a very useful and reliable device, it can save your plants from suffering and increase your overall outcome. Give yourself a little peace of mind and install a HLC-3e in your room today.
From CAP -
The HLC-3e by Custom Automated Products protects your garden from overheating and your light from Hot Starts”. The HLC-3e constantly monitors your garden temperature. If the garden exceeds the temperature that you have set, the HLC-3e turns off your lights so that crop damage will not occur. It then turns on the “Temp Exceeded” light to let you know that an overheating situration occured. When the temperature returns to normal, it will turn your lights back on.
The HLC-3e also constantly monitors the power going to your light. In the event of a power failure, it will not allow the light to restart until 15 minutes after the power is restored. This prevents your light from attempting to “Hot Start” your bulb, preventing bulb damage and increasing bulb life.
The HLC-3e comes with a 15′ remote temperature sensor. The HLC-3e is rated at 15 amps @ 120 volts. 3 year warranty.
You can buy any CAP product at any of our stores or online
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