Most Frequently Asked About Supplements 101: Part 2

In my last article titled “Most Frequently Asked Questions About Supplements 101” I began to shed some light on the more popular hydroponics supplements, including Humic Acid, Gibberellins, Seaweed and Rock Dust. In this follow up, I decided to dig a little deeper down the rabbit hole in hopes of inspiring you to try some of this cool stuff at home. Now if you’re an adult, make sure you get children’s permission first!

The Growth Stimulators

Benzylaminopurine:

An important cytokinin derived from vegetative sea life (which activates basal shoot formation, cell division, lateral bud creation, improved flowering, and fruit production), 6-Benzylaminopurine also inhibits senescence, which means your plants will keep producing longer than before. 6-Benzylaminopurine has been found to increase leaf surface, stem thickness and the number of lateral branches. At the same time, root growth is slowed down. This is very likely because the larger leaves provide more nutrients to the plant and reduce the need for root mass. At higher concentrations of 300 to 400 ppm, stem elongation was reduced. My own experience using Benzylaminopurine in a deep water system worked wonders by keeping roots bright white over the control plants in a duplicate system. When used with gibberellins, a fruit’s shape can be significantly improved.

Application:

The Ontario Hosta Society reports¹ that wetting a hosta leaf with 1000 PPM to 3000 PPM will cause the plant to branch out similar to cutting the end of the branch, without the damage that pruning would cause. A Plumeria Society Research Bulletin² also reports that if a branch is pruned, 6-Benzylaminopurine will generate more branches than pruning alone.

¹www.rittenhouse.ca/hortmag/Hosta/Hosta-Spring00.htm

²www.theplumeriasociety.org/prb/prb-_1-2html

Brassinolide:

A natural plant hormone that promotes growth, increases yields in grains and fruit crops while making plants more resistant to drought and cold weather, Brassinolide was first isolated from the rapeseed plant pollen (Brassica napus L.). Related compounds, called brassinosteroids, are found in a wide variety of plants. Essential for all plant growth; plants that cannot generate their own brassinolide will become dwarfs¹. In fact, it has been suggested² that the more brassinolide is available to the plant the more it will grow. Brassinolide improves photosynthesis, which makes plants grow faster, and it increases a plant’s resistance to cooler temperatures, drought and disease.

¹Carnegie Institute [http://carnegieinstitution.org/Yearbook_HTML_00_01/dpb.html]

²Genetically Altering the Appearance of Crops [www.angelfire.com/oh/geneticsgroup7/heater.html]

Application:

Concentrations of brassinolide are based on many different factors, such that hard rules are hard to define. In research brassinolide concentrations of 0.01 ppm¹ to 0.5 ppm have shown very good results² ³ across a wide range of plants.

¹www.actahort.org/books/239/239_54.htm

²www.tnau.ac.in/cbe_crophy.html

³www.tnau.ac.in/tech/ricetips.pdf

Gibberellic Acid:

While this was covered in detail in the first installment of this article, I thought it belonged here as well. Gibberellins were discovered by Japanese plant pathologists studying “bakanae” disease (“foolish seeding”) of rice, in which seedlings grow elongated and die. In 1898 Shotaro Hori demonstrated that it was caused by a fungus, now known as Gibberella fujikuroi. In 1926 Eiichi Kurosawa reported that a chemical produced by the fungus caused the symptoms, and that the substance was heat-resistant, not losing its activity after four hours at 100°C (212°F). In 1935 Teijiro Yabuta first isolated a non-crystalline solid and named it Gibberellin. In 1938, Yabuta and Yusuke Sumiki first isolated a crystalline compound from the cultured fungus. Since this time, 79 different gibberellins have been isolated, many of these from the seeds of a wide variety of species. Gibberellic acid-3 (GA-3) is the most widely used, and is produced commercially by growing the fungus in huge vats and then extracting and purifying the GA-3. Gibberellic Acid is an important plant hormone used to speed germination, plant growth and overall size. Gibberellic acid can also be used to influence the onset of flowering, flower sex and size. The main areas of activity are to speed seed germination, grow larger plants, and manipulate the gender of flowers. There are also some reports that it will also generate a larger number of female plants. This aspect is generally undocumented and requires research. Depending on how you use gibberellic acid (GA3), you can generate male flowers on a female plant and use the pollen from the same plant to generate female clones of itself or to pollinate another female plant.

Application:

The results of gibberellic acid (GA3) applications vary depending on many factors, including (here also) the type of plants it’s applied to. In one study of persimmon yield¹ it was found that applications of 15 to 30 PPM increased yields by 50% to 400%. In another study² it was even found that if gibberellic acid is applied to a plant, the next generation of the plant would also benefit from faster flowering and increased height. In another study of walnut trees it was found that applications of gibberelleic acid (GA3) increased growth by 567%³.

¹Increasing Persimmon Yields with Gibberellic Acid [www.actahort.org/books/120/120-_32/htm]

²Generations Living with Gibberellic Acid [www.sidwell.edu/us/science/vlb5/Independent_Research_Projects/cgraham/]

³Gibberellic Acid for Fruit Set and Seed Germination [www.crfg.org/tidbits/gibberellic.html]

Kinetin

Kinetin is a trade name for part of a group of hormones called cytokinins (from Ascophyllum Nodosum) which promote cell division. This was also covered in detail in the first installment of this article, but I felt it just to repeat it here. A study by N. Roychowdhury¹ showed that 25 PPM and 50 PPM kinetin improved both the size and number of flowers.

¹www.actahort.org/books/246/246_31.htm

Application:

A study by N. Roychowdhury¹ showed that 25 PPM and 50 PPM kinetin improved both the size and number of flowers.

¹ www.actahort.org/books/246/246_31.htm

Mono-Silicic Acid:

The plant-available portion of the silica that makes up over 40% of soil chemistry, and is generally present in plant tissues in amounts in the neighborhood of that of macronutrients (N, P, K, Ca, Mg, S), and in some grasses and grass family crops, often at higher levels than other macronutrients. Available silicon is removed from the soil by farming and weathering, while it is typically not replenished by any fertilization program. Plants grown in soils with low soluble silicon levels have a greater susceptibility to disease, drought stress and other plant stresses. Silicon has been shown to reduce phosphorus leaching while at the same time increasing phosphorus plant availability. Silicon’s activity in the soil matrix has been proven to improve micronutrient uptake (boron, copper, iron, manganese, zinc), and reduce toxic metal uptake (aluminum and sodium amongst other heavy metals).

Application:

Most quality Humic Acids have mono-Silicic Acids in them. I’ve never used it by itself so I can’t make any recommendations other than to look for it in Humic/Fulvic products.

Triacontanol:

This is a natural plant hormone that promotes growth. Triacontanol raises yields by improving photosynthesis and cell division. Different studies will give different results due to different factors, such as the type of plant tested and environmental factors. One study reported that triacontanol improves photosynthesis and plant yield by as much as 100% while another reports improvement of 15% to 30%. A third reports that small amounts will improve vegetable crop yields by 30 to 60%. My own experience is more like 10 – 15%. Applicaton:

One published recommendation¹ has been to spray a one to two PPM triacontanol solution at two different times. The first is 15 days after transplanting the plant and the second time when the plant is at full bloom.

The Growth Regulators

Mepiquat Chloride

A plant growth inhibitor used to control growth with benefits of better plant flowering, reduced plant height, enhanced crop earliness, and in some cases improved yields. Mepiquat chloride is heavily used in the cotton industry.

Plant growth inhibitors are a popular tool for the advanced gardener. It seems strange to want smaller plants, but how about getting better flowers? Plants have a certain amount of resources stored in roots, leaves and other areas. It also continues to generate more resources from sunlight and soil. When a plant goes from vegetative growth to flowering it usually continues some growth. But what if a plant would stop growing and concentrate all its resources in flowering? Obviously, it would have much more impressive flowering. Application:

According to research¹ concentrations of 10 PPM work best, while more than 10 PPM doesn’t seem to give any better results.

¹www.deltapine.com.au/info_centre/esm_managinggrowth.htm

Root Stimulators

Indole-3 Acetic Acid (IAA)

This is the most effective and active plant hormone, and the most active auxin. Indole-3-acetic acid (IAA) stimulates the growth of the main stem (apical dominance) and reduces the growth of side branches. IAA is a tricky product to use - at high doses, growth is inhibited, and at small doses IAA can rapidly increase cell wall size in young stems. For cloning, IAA promotes healthy callus formation and is a great way to root cuttings. During production, it can influence the formation of flowers and seedless fruit while improving plant respiration and the creation of proteins. In growing plants Indole-3-Acetic Acid (IAA) is produced in the tip of the main stem. As Indole-3-Acetic Acid (IAA) is produced it inhibits the growth of side branches. When the tip is removed by pruning, the side branches will grow faster. Application:

IAA dissolves very poorly in water. One website¹ recommends dissolving IAA in 95% ethanol. We have been quite happy dissolving 1AA in 99% methyl hydrate.

Indole Butyric Acid (IBA)

This is the leading plant hormone used to promote the formation of roots in plants and to generate new roots in the cloning of plants through cuttings. In one research project it was concluded that kinetin (1250 PPM) and IBA (2500 PPM) gave 218% more rooting than a control group.

Another study also concluded that combining IBA and NAA at 250 PPM gave better results than using only one hormone. Given that kinetin degrades very quickly there is a clear preference for combining IBA with NAA instead of kinetin.

Application:

The results will depend on the type of plant. One study¹ concluded that for transplanting rice plants, soaking roots in a 25 PPM concentration of indole-3-butyric acid (IBA) gave the best results. Another source ² recommends using 6000 PPM for kiwi rooting.

Napthalene Acetic Acid (NAA)

Napthalene Acetic Acid can significantly increase the number, length and dry weight of root hairs, small roots and large roots.

In an experiment on date palms the effects of IAA, IBA and NAA was tested. The notable conclusion of the experiment was that on these existing roots NAA 50 PPM and 100 PPM promoted growth while IBA slowed it down. Application:

In an experiment on date palms the effects of IAA, IBA and NAA were tested. The notable conclusion of the experiment was that on these existing roots NAA 50 PPM and 100 PPM promoted growth while IBA slowed it down.

Fungicides

Validamycin

Validamycin is a natural plant antibiotic that eliminates the fungi that attack roots. It is effective in protecting seedlings and cuttings against damping-off and is easily dissolved in water.

Application

When used in liquids one publication suggests an application of 0.2% or 2000 PPM. Please remember that the exact amount would vary, depending on the type of crop and the particular problem being dealt with.

Hydrogen Peroxide

H202 is naturally found in rain and snow. It is formed when water is exposed to Ozone (O3) in the upper atmosphere. When H2O2 comes in contact with organic impurities, the extra Oxygen molecule is released and oxidizes the impurity, rendering it harmless. The original H2O2 molecule is now H2O (water). Our own immune system produces and uses Hydrogen Peroxide to control bacteria and viruses inside our own bodies everyday. Hydrogen Peroxide is a very versatile material for cleaning and disinfecting hydroponics systems between crops, and to safely raise the level of dissolved Oxygen in your nutrient solution. Regular treatment helps to stave off harmful pathogens including pythium, rhizoctonia and phytophthora, the three most destructive organisms in the garden. The extra Oxygen that is released also serves to stimulate growth. Once diluted according to the manufacturer’s directions, H2O2 may be used as a foliar spray, watered into pots and planters or added to hydroponics reservoirs to immediately start performing its intended functions. It comes in 3%, 19% and 35 % concentrations. The last concentration is considered a hazmat and cannot be shipped through the US mail, only by freight with full disclosure and any applicable Hazmat fees paid. Application:

Dilute to three percent working solution using distilled water only. Use 1-2 teaspoons per gallon added to your reservoir before adding nutrients. Refresh every 3-4 days.

Media Microbiology

Know your media microbiology. All the microorganisms listed below feed on organic nutrition (sloughed root cells, exudates or organic matter) in order to grow, multiply and provide numerous plant health care benefits:

Plant-Growth-Promoting (PGP) Rhizobacteria:

These bacteria produce a variety of chemicals that stimulate plant growth. The bacteria grow and persist in the rhizosphere of non-woody roots.

Free-Living or Non-Symbiotic

Nitrogen-Fixing Bacteria:

Very specialized bacteria that fix atmosphere N and increase plant growth due to increased nitrogen nutrition. These bacteria are intimately associated with the rhizosphere of roots.

Phosphate Solubizing Bacteria (PSB):

Certain soil and rhizosphere bacteria that produce phosphatase enzymes that in turn solubilize phosphorus (P) from insoluble mineral sources. PSB+myorrhizal=increased plant growth and increased P available from mineral P.

Symbiotic Nitrogen-Fixing Bacteria:

Most legumes (beans, peas, clover) in natural small medias form N-fixing nodules with Rhizobium bacteria species. N-fixation by Rhizobium nodules is greatly enhanced by vesicular-arbuscular mycorrhizal (VAM). Certain trees, i.e. alder and Casuarina, form VAM and N-fixing nodule with actinomycetes organisms called actinorhizae. Bacteria and Fungi Antagonistic to Root Pathogens: Many soil bacteria and fungi during normal growth produce antibiotics or are hyperparasitic on harmful fungi. As a result, they inhibit root pathogenic organisms. VAM and ecto mycorrhizal increase populations of these beneficial microorganisms in the rhizosphere, which contributes to the control of root diseases.

Mycorrhizal Fungi

A lot of information is available about these little helper fungi who share a symbiotic relationship with plant roots by improving uptake from ten to ten thousand times. It also offers a protective shield that helps stave off root diseases and softens compacted soils and mediums. Mycorrizhas come in two types, Ecto mycorrhizal and Endo mycorrhizal. The Ecto type forms a coating around the root tips by piercing them with its hyphen, but does not attach to the root cells. Ecto form a direct connection with a tuft-like branched structure within the root cells. Mycorrhizal are able to absorb and transport all 15 major, minor and micro elements necessary for growth while protecting your plants’ roots and keeping them healthy from top to bottom.

Compost Extracts and Teas

Compost Watery Extract

This is made from compost suspended in a barrel of water for seven to 14 days, usually soaking in a burlap sack – a centuries-old technique. The primary benefit of the extract will be a supply of soluble nutrients, which can be used as a liquid fertilizer.

Compost Tea

Compost tea, in modern terminology, is a compost extract brewed with a microbial food source – molasses, kelp, rock dust, humic-fulvic acids. The compost-tea brewing technique, an aerobic process, extracts and grows populations of beneficial microorganisms.

What many fail to realize is that for a population of aerobic bacteria to exist within a solution, there needs to be a lot of oxygenation in the reservoir. There also needs to be a home for these beneficial bacteria to live. If you go the compost route, keep these two caveats in mind at all times. It’s a tricky balance getting organics to work properly in an aqueous hydroponics system.

Now that we’ve got the basics out in the open, it’s up to you to put it to work and play. See you next month in Maximum Yield, and as always, have a great time in your garden!

Keith Roberto is the Author of How-To Hydroponics