Plant hormones are chemical substances synthesized by a plant to signal and control cellular processes. These hormones are used to initiate or stop the growth of leaves, roots, fruits, and flowers. Each hormone having specific functions at specific concentrations.
There are five groups of plant hormones namely:
- Auxins: they signal cell growth and elongation in the apex of plants, in small concentrations too, they can signal root formation and elongation. They also inhibit buds lower down the stems from growing so as to ensure increasing height of a plant through its top parts.
- Gibberellins: they promote elongation of stems, cell division and encourage flowering.
- Cytokinin: they work with Auxins in stimulating cell growth and cell division especially in breaking the restrictions originally placed by Auxin against lower buds. They also work with ethylene to signal fruit and leaf drop.
- Abscisic acid: they are primarily growth inhibitors. They stop growth of plants when conditions are not favorable, such as in extreme cold or prevent growth when the time isn’t right i.e. preventing seeds from germinating while still within a fruit.
- Ethylenes: they are fruit ripening agents. They signal fruits to ripen and drop when mature so that you and I can feast. Ethylene is a gas and little wonder other surrounding fruits ripen once one fruit is ripe.
Auxin (Indoleacetic acid) is a naturally occurring hormone in plants that stimulate root and bud development. Synthetic compounds similar to Auxin in structure such as indolebutyric acid or naphthaleneacetic acid are used as plant rooting hormones to encourage the growth of roots when cloning plants.
Cloning refers to the process of making several copies of a mother plant by using a cutting from it. It is a very good way to ensure certain plants of value to the gardener are always available all year round.The rooting hormone is often sold as a powder, but it’s also available in liquid and gel forms.
POWDERED ROOTING HORMONE
The biggest advantage of powdered rooting hormone is its long shelf life when properly stored. This advantage makes it well sought after by many commercial growers.
To use this form of rooting hormone, dip the end of the cutting into the powder, tap the cutting lightly to remove the excess, then transfer it to the desired rooting medium or into the soil. To increase the amount of powder that sticks to the cutting, the tissue can be dipped in water before being dipped into the powder. Do this with a very small portion of powder to reduce the likelihood of contaminating other cuttings.
LIQUID ROOTING HORMONE
They are usually in either a pre-mix/ready to use form or in a concentrated form that further requires dilution. This gives the opportunity to use higher concentrations for woody stems which usually requires higher concentration of rooting hormone unlike softer stems such as Aloe.
To use the liquid form, dip the end of your cutting into a cup containing a little quantity of the hormone for a few seconds. Take care not to keep the cutting in the solution for more than 5 seconds as the plant can absorb more than the necessary amount leading to yellowing or burning of the plant.
GEL ROOTING HORMONE
The gel form is the easiest to apply as the gel tends to stay on the plant stem or cutting better than the powdered or liquid hormones do.
To use the gel, dip the cutting to a quarter inch height into a bowl containing a small portion of the gel. Insert the cutting directly into the rooting medium as the Gel form yields the best result when the cutting is planted in a rooting medium and not in water.
Proven alternatives to the above mentioned that gives similar rooting effect includes honey, willow tea, aspirin, cinnamon and apple cider vinegar.
It is important to note the following when cloning plants:
- The use of rooting hormones is not always necessary but it does increase the success rate by encouraging the rapid and healthy onset of new roots.
- Always dip cuttings into a small portion of the rooting hormone to prevent spreading infection and contaminating the entire source.
- Always follow the manufacturer’s instructions while applying or diluting rooting products.
- Take note of the specific concentration required for the propagation of each plant.