The Best Rooting Hormone for Cacti: Indole-3-Butryic Acid (IBA) Powder Explained
Rooting hormones are naturally occurring or synthetic substances which are widely used in the horticulture industry to strike and accelerate the formation of healthy roots in all types of plant cuttings. They generally come in the form of a powder or a gel, and there are a few different types to choose from. In this article, we’ll cover the three main types: Indole Acetic Acid (IAA), Indole-3-Butryic Acid Acid (IBA) and Naphthalene Acetic Acid (NAA) and provide our recommendation for the best for cacti cuttings specifically.
The discovery of plant hormone responses dates back to the observation that light influenced the direction of growth in plant coleoptiles during seed germination. In the early 1900s, Fritz Went and other researchers found that these effects could be induced through plant extracts containing the auxin Indole Acetic Acid (IAA). Auxins play a crucial role in plant growth, including assisting in the rooting of cuttings.
What’s the best rooting hormone for cacti?
The clear winner is Indole-3-Butryic Acid (IBA).
While Indole Acetic Acid (IAA) is the most prevalent naturally occurring auxin in plants, it quickly breaks down and for that reason it’s not frequently utilised in propagation.
Indole-3-Butryic Acid (IBA) is another auxin that is found naturally in plants. It works by being converted into IAA by the plant and is essentially a precursor to IAA. By using IBA rooting hormones you are providing your plant with an abundance of building blocks that it can use to produce a large volume of readily usable IAA naturally.
Naphthalene Acetic Acid (NAA) is a fully synthetic auxin that resembles IAA in structure but is more effective in promoting rooting and is more stable. Whilst studies have concluded that is effective as a rooting hormone, its toxicity to animals including humans is of reasonable concern.
Even if you weren’t concerned about the toxicity of NAA, IBA is still the clear winner from a performance standpoint. Numerous studies have concluded that IBA results in a greater number of roots in a shorter period of time than any alternative. Below is a chart from one such study:
Image credit: The University of Florida
More about Indole-3-Butryic Acid (IBA)
Indole-3-Butryic Acid (IBA) rooting powder is a widely utilised plant hormone in horticulture, known for its ability to encourage root growth in cuttings and tissue cultures. This hormone is present naturally in plants and plays a critical role in regulating a range of growth and development processes, including root initiation, stem elongation, and fruit maturity.
How it Works:
Conversion to Active Auxin (IAA): IBA is structurally similar to indole-3-acetic acid (IAA), the primary natural auxin in plants, but it requires conversion to IAA to have its full effect. This conversion occurs through enzymatic processes within plant cells. Once converted, IAA can directly participate in biochemical pathways that initiate root growth.
Stimulating Root Cell Division and Elongation: IAA enhances the expression of specific genes related to root cell division and elongation, particularly in the root meristem regions. It influences proton pumps in the cell membrane, lowering pH in the cell wall and activating expansin proteins that loosen the cell wall structure, making it more flexible for cell expansion.
Gene Expression for Root Initiation: IAA activates genes involved in the early stages of root development. This includes genes that promote cell cycle progression and differentiation of cells into root tissue, particularly in the stem cuttings' base.
Nutrient Mobilization and Transport: Auxins like IAA help direct the transport of nutrients, particularly carbohydrates and amino acids, toward the developing root zones. This nutrient mobilization provides the energy and building blocks needed for new root formation.
Cross-Talk with Other Hormones: IBA and its conversion to IAA influence the balance with other hormones like cytokinins and gibberellins. High auxin levels in a cutting's base, relative to cytokinins, favour root initiation over shoot growth. This hormonal cross-talk helps regulate the overall rooting process.
Cacti are renowned for their toughness in the face of harsh and unpredictable growing conditions, but some species can be difficult and slow to propagate. This is where IBA comes in - the hormone acts by speeding up root formation, thereby helping the cutting to establish itself faster and minimise any undesirable growth formations such as etiolation resulting from prolonged nutritional deficiency. Put simply: a shorter rooting timeframe lessens the stress that cuttings often endure while rooting.
Because of this, the use of IBA rooting powder with cacti can play a role in reducing the chances of disease and infection. Cuttings are more susceptible to pests and illnesses during the rooting phase, and IBA can aid in fortifying the plant's defence and minimise its susceptibility.
To sum it up - IBA rooting powder is a powerful tool in promoting root growth in cacti cuttings, reducing time to root whilst simultaneously increasing the number of robust and healthy roots on a cutting. This leads to healthier and hardier plants in a shorter time frame, and who doesn't want that?
Is gel or powder rooting hormone better for cacti?
Powder is preferable for cacti. Whilst both products are generally interchangeable in their effectiveness for other plants, we only recommend using powder rooting hormones for cactus cuttings. The reason is two-part and simple. Firstly, dipping a freshly-cut and still-wet cactus cutting into a plate of powder will ensure excellent adhesion and even coverage of the hormone - it’s easy, quick and not messy. Secondly, unlike most other species of plants, we want our cactus cuttings to dry out, not stay wet - a powder will aid and speed up this drying process, whereas gel will delay and inhibit it.
Product Recommendation
We exclusively use Rootex-P rooting powder. Rootex-P is a high-quality Indole-3-butyrate (IBA) rooting powder manufactured in Victoria, Australia which we are happy to endorse for all of our customers.
The active constituent in Rootex-P is 3g/kg Indole Butryic Acid (IBA).
To use with cacti: simply dip the cut end of your cactus into the powder and then leave the cutting to dry in a bright and well-ventilated area out of direct sun or rain. Then follow the normal rooting procedure. Do not wet/mist the soil as the packet instructs or your cactus cutting may rot.
For anyone wondering: whilst we fully endorse the benefits and safety of IBA rooting powder, the cuttings for sale on our website have not been treated with it. We believe our customers have the right to decide whether they want to use it. If you’d like to purchase rooting hormone powder, we sell it here.
