The Various Forms of Rooting Hormones & Organic Rooting Stimulants

In horticultural terms, cloning refers to the process of making duplicate plants out of a cutting from a mother plant. It is a great way to keep certain plants around that are very productive or otherwise beneficial to the grower.

To maximize production of an indoor garden, many growers rely on cloning to provide a continuous supply of young plants. Put another way, if you are already growing a particular plant that is productive and suitable for your environment, you should clone the plant to ensure the next harvest is just as productive.

Aside from atmospheric conditions during the cloning process, which must be kept consistent, the rooting hormone or agent you use to help promote the fast, healthy onset of new roots is another factor that contributes greatly to the success or failure of cloning.

Read also: The Science Behind Natural and Synthetic Root Growth Promoters

What is a Rooting Hormone?

A rooting hormone is a naturally occurring or synthetic hormone that stimulates root growth in plants. You might be surprised to learn that most plant cuttings will naturally produce their own rooting hormones after a short period of time. In fact, many plants can easily be cloned by simply placing the cutting in some clean water.

However, some plants are finicky and do not grow well with this method. Other plants may take a really long time to develop roots without the use of a rooting hormone. This slows down the production of the entire garden. The use of a rooting hormone will also generally provide more consistent results than cuttings placed in just water.

Auxins are one of the main plant hormones that aid in the creation of initial root growth. More specifically, indole acetic acid (IAA) is the natural auxin found in plants that is responsible for natural root stimulation.

IAA is involved in just about every aspect of plant growth and development, including the formation of embryo development, induction of cell division, stem elongation, vascular tissue differentiation, fruit/flower development, tropic behaviors (leaves and stems moving toward the light source) and the induction of rooting.

Most rooting products do not contain IAA but rather a synthetic form of indolebutyric acid (IBA) and/or napthaleneacetic acid (NAA). These rooting hormone products come in different forms, each with their own advantages and disadvantages.

Read also: A Simple Guide to Taking Plant Cuttings

Plant cutting dipped with powder rooting hormone. Source: iva/Shutterstock

Forms of Rooting Hormones

Powder Form – Powder form rooting hormone products have been used by commercial and hobbyist growers for many years. The biggest advantage of these products is their long shelf life. When kept dry, powdered rooting hormones can last many years. Because of its stability, powdered rooting hormones are still used by many commercial growers.

To use a powder form rooting hormone product, the cutting is dipped in the powder, then tapped lightly to remove the excess. The cutting can then be placed in the desired medium for rooting.

To increase the amount of powder that sticks to the cutting, the stem tissue can be scored or dipped in water before being dipped into the powder. However, this may increase the likelihood of contamination from cutting to cutting and will use up the batch of powder more rapidly. Using small batches of powder for dipping cuttings is the key to reducing the likelihood of contamination and making the most efficient use of the powder.

Liquid Form – Liquid rooting hormone products come in two forms: ready to use and concentrated. The ready-to-use liquid rooting hormones are convenient and usually contain the appropriate percentage of synthetic hormone for speedy root development.

Be sure to always pour a small amount of the liquid into a separate container rather than dip the cuttings directly into the bottle of liquid rooting hormone. This will reduce the chance of spreading disease and contaminating the entire contents of the bottle.

Concentrated liquid rooting hormone products require dilution before use. Although concentrated liquid rooting hormones require an additional step, they provide a more customizable rooting hormone. In other words, you can determine the concentration of a synthetic rooting hormone in the final solution. This can be advantageous if you are growing a wide variety of strains.

Some plant species will require higher concentrations than others. For example, a woodier tissue plant may need a concentration twice as strong as that needed by softwood cutting varieties.

All in all, liquid rooting hormones in a concentrated form provide the most versatility to the grower. They usually have a shorter shelf life than powders and may even require refrigeration.

Read also: Starting Plants from Cuttings

Gel Form – Rooting hormones in gel form have become the most popular rooting hormones among indoor growers. Of all the forms of rooting hormones, gels are the most convenient to use.

Gel products have the appropriate levels of synthetic rooting hormones for most plants and are ready to use right out of the container. As with the other rooting hormone products, a small amount of gel should be placed in a separate container for dipping the cuttings to avoid the possibility of contamination.

Gels have another distinct advantage: they completely cover the cut section of the new plant with the synthetic hormone and keep it covered. This allows the plant tissue to absorb more of the synthetic hormone. Gels are also less likely to wash or rub off in clone machines or other cloning devices where cuttings are misted with water.

Although you get more bang for your buck with powders and concentrated liquids are more versatile, cloning gel is still the go-to rooting hormone product for indoor growers.

Read also: Pest and Pathogen Prevention in an Indoor Garden

Honey can be used as a natural rooting stimulant. Source: Sunvic/Shutterstock

Natural & Organic Rooting Stimulators

There are many organic purists in the indoor growing community who struggle with the cloning stage because they do not want to use synthetic hormones. No need to worry! There are two natural and organic sources that can successfully provide a rooting boost to freshly taken cuttings. These two stimulants are honey and willow extract.

Honey – That’s right! Honey can be used as a natural rooting stimulate. The reason honey works well as a rooting hormone is due to its natural antiseptic and anti-fungal properties. In other words, honey protects the tender cuttings from pathogens and allows the natural rooting hormones to work their magic.

Although results will not be seen as quickly as when a synthetic rooting hormone is used, honey is a great natural cloning agent that will allow growers to achieve high success rates during cloning. To use honey as a cloning agent, simply dip the cutting into the honey to create a thin layer over the cut tissue.

After dipping into the honey, place the cutting into the desired medium. Many synthetic rooting hormones will help the plant create roots in three to five days. Growers who use honey for their cuttings can expect root formation in seven to 14 days.

Growers can experience root growth in a matter of days when using willow extract as the rooting stimulator. Source: kazmulka/Shutterstock

Willow Extract – Willow extract is probably the best natural, organic rooting stimulator available. There are many products available that use it as the main ingredient. The reason willow extract works so well is because it contains two auxin hormones: salicylic acid (SA) and indolebutyric acid (IBA). SA is involved in signaling a plant’s natural defenses, while IBA—once thought to be only available synthetically—stimulates root growth.

This hormone is found in high concentrations in the growing tips of willow branches. Products made with willow extract contain these two powerful hormones and can naturally provide the same success rates as synthetic rooting hormone products. In fact, it is not uncommon for growers to experience root growth in a matter of days when using willow extract as the rooting stimulator.

Read also: Help Your Plants Help Themselves: Enhancing Natural Defenses

Additional Rooting Tips

An effective rooting stimulator is an important part of successful cloning, but there is also much to say about other contributing factors. Consistent environmental conditions are also crucial in obtaining reliable cloning results.

Cleanliness is an extremely important factor during cloning as well. Sanitizing and sterilizing equipment between clone batches is essential for creating healthy clones. Also, a clone is only as good as the mother plant from which it comes. Simply put, only take clones from healthy, vibrant donor plants.

When an effective rooting stimulator, whether it be a synthetic hormone or natural derivative, is combined with solid environmental conditions, sterile equipment and a healthy donor plant, you are sure to be successful during the cloning stage of your garden.

With a continuous supply of healthy clones, you can perpetually rotate new plants into the vegetative and flowering areas as needed. Just remember, the prosperity of a perpetual garden is based entirely on your ability to create healthy clones.

An effective rooting stimulator product helps ward off diseases, increases the rate of root initiation, and helps lay the groundwork for a more productive growroom.

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