In Canada as in the UK we experience seasonal changes and many outdoor growers who get down and dirty outdoors take flowering and fruit development for granted.  It is true that photoperiod change is a major contributor to the success of most crops’ success, and full credit to the sun for helping out!  But science is giving us insight into working with light to supercharge the flowering process together with the supplements we add.

The key question is:  What is going on inside your flower crop, and how can you work with your light source to accelerate the process and achieve the best yield possible?

Although the contents of this article could apply to outdoor growing from the summer solstice through the autumn, most urban gardeners don’t have much outdoor space and have taken their activities indoors.  In an indoor setting the photoperiod is changed manually by adjusting your light timer setting and shortening the length of your light cycle.

There are many options available for flower production and the choice can be quite overwhelming in your local growshop.  First and foremost, look to the shop owner for guidance – but even after you’ve heard their advice you must test what premium products are doing for you, and whether they’re providing the benefits you’re looking for.

Techniques for triggering flowering

When triggering flower development it is important to plan for your plants’ success.  Make sure you are transitioning your fertiliser levels properly to provide your crop with the best opportunity possible.  For example, a quick foliar spray of kelp meal a week before flowering can provide key signals to developing sites increasing cell division, promoting lateral branching and relieving some of the stress associated with initiating blooming.

There is also an emerging group of products based around this transition stage meant to stimulate key reactions within the plant, forcing it to increase flower site development.  By adding these products before flowering and into the initial flowering stage you can achieve a noticeable and positive change in flower development.  I know several people that are now adding these products but are also experimenting with a more gradual photoperiod change.

Outdoors the natural cycle of seasonal change is slow and flowering is induced over several weeks.  Some experienced growers are now toying with their light cycle by adding 7 to 10 days to a plant’s flower cycle and adjusting the light cycle by an hour every couple of days.  Initial results have shown that if you have extra days to play with you can decrease the internodal stretching, keeping your plants a little more compact.  This could be a result of providing your plant the additional time to adapt and change certain chemical reactions during this transitional phase.

Primary Nutrients

Primary nutrients are essential for plant growth and development, especially during the flowering stage where plants are forced to expend a staggering amount of energy.  Nitrogen, Phosphorous and Potassium all play a vital role in this amazing transformation.

Nitrogen

Upon entering the plant most nitrogen will be worked into the chloroplast where it is a key component to the formation of chlorophyll. Although nitrogen is exceptionally important in vegetative growth it is also a key to successful flowering at a lower level.  Nitrogen is essential in the formation of proteins and amino acids which can have serious effects on flower development.

Phosphorous

Develops a larger root system to feed flowers and is involved in the Kreb Cycle and the Calvin Benson cycle, essential for energy production and energy movement within the plant.  No phosphorous = no carbohydrates.

Potassium

Assists with chlorophyll production, starch formation and the movement of those sugars to the flowering sites.

Secondary Nutrients

Secondary Nutrients can be a lynch pin for success, as many nutrient deficiencies during a flowering period are related to the mobility of secondary elements.
Calcium is a backbone for cellular structure, and is very important for heavy flowering plants to reduce weight related stress.  Calcium is immobile once set in the plant so adding calcium throughout flowering is very important.

Magnesium is a co-factor in enzyme reactions and essential to chlorophyll production. It is a key to a flowering plant’s success.

Sulfur works to increase proteins and oil development while building vitamins and amino acids.

Micronutrients

Micronutrients are those elements required by plants in microscopic amounts.  But don’t underestimate their importance!  Many of them play a critical role in developing amino acids and propelling rapid photosynthesis.  Although these compounds are important to flowering I’ll save their discussion for a future article.  All good quality nutrients should be providing all necessary micronutrients.

Co Factor Elements

Co factor elements are a fairly new consideration in high tech flower production.  These elements are not considered essential for plant growth but they have been shown to influence reactions involving other elements, and provide additional benefits to the plants.  There are several elements that have been studied including: Cobalt (Co), Silicone (Si), Nickel (Ni) and Vanadium (V).  There are also ongoing studies on at least 10 other elements, which show some type of benefit to the plant.  There is also the concept of biological transmutation, but again, this is definitely a story for another day!

Synthetic or natural chelates?

Synthetic or natural chelates can be very important for nutrient availability and uptake within the plant.  Chelates form a bond with an element.  This bond or coating helps the molecule become more available to the plant (easier to absorb).  Synthetic chelates are generally used with micro nutrients such as iron and can be seen on the label expressed as EDTA, DPTA and others.  Caution should be used with synthetic chelates which can be phytotoxic at higher levels.  Natural chelates are found in humic acid, fulvic acid and in some forms of amino acids.  Humic and fulvic acid are both derived from leonardite coal which is a type of shale rich in hydrocarbons.  These extractions can seriously affect the rate of growth in plants and can be used in all stages of development.  A good rule of thumb is to use humic in soil and soiless situations which have a more neutral pH and fulvic acid in water culture where pH is generally slightly more acidic.  Fulvic acid is also a must for any foliar spray as it helps with nutrient rich spray being absorbed through the leaves.
Natural chelates are excellent for pumping more nutrition into your plants and stimulating microbial activity in your medium but because they are a carbon based molecule they also effectively add more carbohydrates (sugars) as they cycle through the plant.  Some veteran gardeners even recommend foliar spraying fulvic acid during late flowering on oil producing flowers to increase oil content and also induce a more fragrant aroma.  I’m not sure I endorse foliar spraying plants late in a flowering cycle but the gardener is always right!

Carbohydrates

Carbohydrates are the basis for most life on earth and are the basis for energy in all plants.  Carbohydrates are formed from carbon, hydrogen, and oxygen.  The photosynthesis reaction uses the sun’s energy to bind the three elements into sugars. Monosaccharides are simple sugar for fast conversion (glucose), while disaccharides are still fairly easy to convert(sucrose).  Polysaccharides are groups of sugars that from more complex bonds such as starches and cellulose.   Adding in carbohydrates during flowering can provide critical energy for your plants to supplement internal production.. As with many other topics discussed in this article this is a vast topic that will need a closer look in future write ups.

Enzymes

Enzymes are created by nearly all living creatures, including plants, using energy reserves from metabolism.  Supplementing with a high quality enzyme can provide a great insurance policy for important crops.  Good quality enzymes can be an expensive purchase and are not for indiscriminant use but under the right circumstances they are worth their weight in gold.  During the flowering cycle the primary function of enzymes would be to “clean up” the medium by decomposing organic waste.  This reduces the likelihood of developing a root based pathogen problem (ex. Pythium).  While keeping your medium clean a quality enzyme supplement will also be breaking down cellulose (polysaccharides) from dead root material, which will decompose into useful carbohydrates (monosaccharides) these will be reabsorbed into your plant providing additional sugar energy during peak flowering.  The three broad groups of enzymes used by plants are cellulose, protease, and amylase which break down cellulose, proteins and starches.

You are at the cutting edge!

The science found in some of the products on the shelf in hobby stores is virtually on the cutting edge of technology.  As an urban gardener it is up to you to test these products in your own garden and determine whether the benefits are worth the price-tag.  Remember that every plant and every situation is different so by testing various products you are working to improve your own success.  Always return the favour to the store owner that offered advice by giving them the feedback from your trials to pass along to other curious gardeners.  Now get back to growing!

Simon Hart is the senior technical advisor for Grotek Manufacturing in Canada.  If you have any questions regarding flowering or anything else garden related you can email Simon at simonh@grotek.net

Thanks to urbangardenmagazine for the article – Original Page Here