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The parallels between alchemy and hydroponics are numerous. Countless hours spent tucked away in a basement or attic, tinkering with outlandish contraptions, carefully measuring concoctions, scribbling notes in the half light and endlessly muttering to yourself. Then there are the cautious misgivings of the mostly mistrusting world at large.

In an effort to break through the barrier of ignorance, and hopefully save us from a fiery fate at the hands of the Inquisition, HYDROMAG is here to usher you onwards as you dip a tentative toe into the sloshy world of potions and lotions. Where better to start than with the very substance your plants are most likely to meet first; rooting hormones.

The primary functions of hormones are to regulate metabolism in plants and humans alike. Humans produce hormones in glands. Most of us are familiar with adrenaline and endorphins, produced by the adrenal and pituitary glands respectively, and no one can deny the central role they play in our lives. Plants, as ever, have us at a disadvantage in the biological stakes when it comes to hormone production. Every cell of a plant is capable of producing hormones and transporting them to the place where they are most needed.

Plant hormones (phytohormones) work in conjunction with one another. Variances in the concentration of the constituent hormones determine the functions performed by a particular hormone mix.

Fundamentally, low concentrations of plant hormones stimulate growth, while high concentrations inhibit growth. Plant hormones are categorised into five major classes, or families if you prefer.

Abscisic Acid (ABA)

Growth hormones, Abscisic Acid, hydroponics

ABA inhibits growth in a plant- which can at first seem counter intuitive – and arguably is so, to an extent, for hydroponic gardeners. In the barren wilds of ‘outdoors’, ABA prevents plants from being tricked by the pesky weather into growing at the wrong time of year- say during an aberrant warm spell in the winter. Plants build up ABA during the vegetative stages of their life cycle. Seeds begin life with a large amount of ABA, which begins to dissipate under the action of other hormones, before the seed can germinate. ABA is essential to plant life though, even if it isn’t a big fan of hydroponic practitioners and their nefarious attempts to betray the natural order by growing strawberries in the middle of winter.

Cytokinins

Growth hormones, Abscisic Acid, hydroponics

CKs stimulate growth throughout the life of a plant; specifically, root growth, leaf growth and internodal length. They work in conjunction with other auxins and help to transport them around the body of a plant.

Ethylene

Growth hormones, Abscisic Acid, hydroponics

Ethylene gas acts on the structure of cells preventing cell elongation. Plants have a geotropic response, which is to say they want to grow upright. When growing straight up isn’t an option, ethylene acts to strengthen the plant and influence it in the necessary direction.

Gibberellins

Growth hormones, Abscisic Acid, hydroponics

Better known to gardeners as blooming hormone; gibberellins act to lessen the effects of ABA, in essence allowing the plant to ‘wake up’ and begin growing. GAs promote healthy cell growth which in turn affects the height of plants. They’re important to germinating seeds and also in healthy fruit development.

Auxins

Growth hormones, Abscisic Acid, hydroponics

Better known to gardeners as rooting gels, powders and pastes; auxins promote healthy root growth and the production of side roots. Indole-3-acetic (IAA) is produced naturally in the young leaves of a plant. Most rooting products use synthetic substitutes to IAA, namely 1-Naphthaleneacetic acid (NAA) and Indole-3-butyric acid (IBA). NAA and IBA are structurally very similar to IAA, but plants are unable to break them down in the same way they would break down their naturally occurring cousin. The advantage of synthetic hormones is, obviously, that the longer they’re present in a plant, the more time they have to work their magic. The disadvantage is that the longer they hang around, the higher their concentration is likely to grow. Higher concentrations act to inhibit plant growth and have the potential to progress up the food chain, potentially increasing in concentration further up the ladder.

The Dark Side

Synthetic plant hormones are highly regulated in many countries, and even banned in others. Despite the fact that synthetic plant hormones are used in exceptionally small quantities for gardening purposes, fears about their proliferation aren’t without a solid foundation. Operation Ranch Hand was an unfathomably evil act by the US Government to utterly decimate Vietnam and her people. Synthetic hormones were the prominent ingredient in Agent Orange- an herbicide sprayed on the country in vast quantities during the Vietnam War. Agent Orange was intended to defoliate the rural areas in which the Viet Cong fought so effectively and force the local population to migrate to US controlled urban areas. Half a million people died as a direct result of this action and a further one million people still feel the direct effects of it today, including a number of the children of US Veterans who suffered birth defects as a result. Not a cheery read, but a very necessary one.

In Practice

Thankfully gardeners use synthetic hormones in very small quantities – in fact if you use more than the smallest amount of rooting gel it will act to stunt the growth of your clones or seedlings. If you’re still hesitant then there are a couple of alternative options open to you. Richard Dennison of Down to Earth Kent Ltd. graciously took some time to give us the rundown on organic, or natural, hormone gels:

Organic rooting gels have made a massive leap forward over the last few years.” He told us. “Generally seaweed products are made from reconstituted seaweed powder which is a commodity that is traded all around the world. To create this dry powder the seaweed is spray dried at very high temperatures which de-natures the natural plant hormones that would otherwise be readily available in concentrate within the seaweed. These are the very same hormones that the cuttings require to produce strong healthy roots and positive early growth.

“The all-natural micronized gel is very rich in growth promoting nutrients that are so beneficial to plant root development and early plant growth.”

The greatest advancement in organic rooting gels has been the use of micronization (finely chopping the seaweed extract into tiny particles) without the seaweed extract undergoing the high temperatures that are used with most seaweed extracts; it is this high temperature that damages the long chain molecules that the cuttings need to encourage successful rooting.

The best seaweed used for this purpose is Ascophyllum nodosum which is harvested at a time of year when the seaweed is undergoing its most rapid growth cycle and is therefore rich in the hormones that cause new cuttings to root, it is then chopped into micro particles (Micronization) to form a gel without having to undergo the high temperatures that are so damaging to the long chain molecules that we are looking to preserve for maximum rooting and early growth stimulation, the all-natural micronized gel is very rich in growth promoting nutrients that are so beneficial to plant root development and early plant growth.

Many people swear by their homemade brews, but obviously results can be mixed across the board.

Richard offered a final word of advice to anyone looking to take the organic path; “Do make sure that (the organic product you choose) is not a reconstituted extract as these will not give the same level of success as cold micronized gels.

As it happens, ‘Cutting Edge’ from Down to Earth Kent is a 100% natural organic rooting gel which fulfills these very parameters. Coincidence? No – Mr Dennison’s willingness to share his extensive knowledge with our readers is, we feel, a fair trade-off for a brief, blatant plug. If you’re a purveyor of a competing product then we’d love to hear from you and put your experience to work for our readership, too.

Finally, you could choose to embody the spirit of our alchemical forefathers by brewing up a concoction of your own. The Internet offers a number of interesting recipes for homemade plant rooting hormones; most involve using willow and/or honey. Many people swear by their homemade brews, but obviously results can be mixed across the board. They do require some legwork and we’re not encouraging anyone to go tearing branches off someone else’s willow tree or raiding a beehive. You might like to check out our article on starting your own colony of buzzing sugar guzzlers though.

We look at the huge variety of fertilizers and feeds available on the market in our ‘Expert Insights’ series and beyond. We’ll also introduce you to some fundamental principles which should underpin your understanding of how, when, and what to feed your plants. For the meanwhile; do you have a warped willow recipe passed down by your Wiccan grandmother? Maybe your organic rooting gel is crafted from the very tears of Gaia herself. Well, if you plan to share them with the world then we’re the people to do it for you – so why not get in touch?

Nitrogen, Phosphorus and Potassium (NPK) form the basis of every nutrient regime. Learn about them here.

This article was originally published in Issue 002 of HYDROMAG (November – December 2012).

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