Marijuana Plant Hormones

Although many marijuana growers don’t know much about plant hormones, the fact is that they are hugely important to any marijuana plant (or any plant at all, for that matter). They signal to the body of your plant that it’s time for the plant to perform certain processes as well as produce certain parts the same way. They are chemicals that are essential to a plant’s well-being.

Marijuana plant hormones: What to use and how to use them:

Hormones are found and created in many different areas of the plant, and then they move to where they need to go. Hormones increase and decrease, according to what the plant needs. Hormones can be added by the grower to help with different processes at various stages of the plant’s life. A thorough understanding of hormones is necessary, however, as they are quite strong in even smaller doses

Marijuana plant hormone products

Rooting Hormones

One of the most common uses of commercial hormone products is to produce clones. These products are often referred to as “cloning gel” or similar products. There are three forms of rooting hormone products: liquid, powder, and gel.

Rooting Hormones Liquid


The liquid form of rooting hormone can be either the ready-made kind or the concentrated kind. The ready-made one is useful because of its convenience since its percentage is generally just right. That said, it’s usually not a good idea to dip the plant straight into the bottle of the product for hygienic reasons.

The concentrated version needs to be diluted before use. This is certainly less convenient, but it is also quite useful for people who know exactly what their plant needs. This is because it can be molded and customized to a specific ratio and concentration.

Product Example:

General Hydroponics Rapid Start for Root Branching – 125 mL ($17.27) 


The powdered form of rooting hormones is generally used by commercial growers, but also some hobby marijuana growers. They are quite useful if you won’t use the whole bottle within one grow season since the powder lasts longer than any other products out there. For that reason, it is preferred by many and can be bought in larger amounts without wasting any of it.

Generally, the method for applying powder is to dip the cutting into some water and then right into the powder and then tap it a bit, so some excess falls off. Then simply put the cutting into the grow medium that you have prepared.

Example Products:

Garden Safe TakeRoot Rooting Hormone – 12 pack ($57.09) 

RootBoost Rooting Hormone – 2 oz. ($6.79) 


The gel version of rooting hormone products is preferred by indoor growers. It is beloved for its high level of convenience as well as great coverage. By great coverage, we mean that it literally can cover the entire stem portion simply because of its consistency. This allows for particularly efficient absorption of the hormones.

To use, put the gel into some kind of container and then dip the cutting right into it. Do not dip it right into the bottle, even though it is temptingly convenient, as that could inadvertently spread disease.

Product Examples:

HydroDynamics Clonex Rooting Gel ($18.99 for 100 mL) 

Quick Clone Gel – 75 mL ($14.97) 

Other Hormone Products

Kinetin (Synthetic Cytokinine)

Cytokinine generally helps with germination, flowering, reduction of aging speed, and when in combination with other hormones (such as auxin or ethylene) they help with mitosis, leaf formation, the aging of leaves, chloroplast development, and so on. The synthetic form of Cytokonine is most commonly Kinetin. Try Bonide Tomato and Blossom Set Spray ($13.89 for 32 ounces), which helps increase crop yields, produce seedless fruit, and increase budding in general.

Also read “How often should I give my cannabis plants nutrients?


Ethylene plays a significant role in the growth of a plant. It ripens fruit faster, thickens the stems of plants, and slows the growth of plants. Too much Ethylene can kill off or harm the plant, so use with caution. When used correctly, it can help form flowers, drop leaves, sprout buds, and germinate seeds.

Ethylene is commonly found in a variety of products. You can find it in any of the following: Arvest, Etherverse, Cerone, Chipco Florel Pro, Prep, Etheral, Flordimex, Flordimex T-Extra, and Bromeflor.


Brassinolide is the steroids of plant hormones. It boosts growth significantly. Overuse is not recommended, but when used properly it helps with hormone regulation, helping with root growth, helping with photosynthesis, helping with phototropism, and more.


Brassinolide is a natural hormone in the Brassinosteroid family of hormones. It can be dissolved in water and put directly on leaves or seeds for germination. You can buy it from Power Grown (10 grams for $17.99).


Jasmonates help with reproductive development, growth, photosynthesis, and defense against external stressors. Use MeJa (Methyl jasmonate) to help with plant defense, germination, root growth, flowering, and more. Jasmonic acid can be purchased to create a spray, as can artemisia tridentate (which is sagebrush that naturally produces jasmonic acid).

How to use marijuana plant hormones

Plant hormones are not used the same way nutrients are, (as part of a daily or weekly regimen). Rather, they should be used intentionally and sparingly, only when specific situations arise or growing phases approach. Much research still needs to be done on the application of plant hormones on marijuana plants, but this information is at least a start to being able to use them safely and effectively.


Gibberellic Acid

When too much of Gibberellic Acid is used, it can be harmful to your plants. In fact, the natural overproduction of Gibberellic Acid is a sure sign of a plant in stress. If you plant is starving, this hormone (and others) will be overproduced and could lead to plant death. Low concentrations of Gibberellic Acid, however, can be highly beneficial.

Germination marijuana seed
Germination marijuana seed

If seeds are in any kind of dormancy (where they won’t germinate), applying a little bit of Gibberellic Acid can help overcome said dormancy. In fact, it could even lead to a faster germination than otherwise. Try using about 2 ppm of Gibberellic Acid on your seeds when trying to get to germination.

Vegetative Phase

Gibberellic Acid

This can also work for young plants after they have germinated. By the time they are developed enough (past being considered “seedlings”), your plants can go through premature flowering from the application of Gibberellic Acid. The application does need to be repeated in order to sustain the flowering.

Hybrid Marijuana Seeds

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Male flowers will begin to form if you use between 10 and 200 ppm, while female flowers will require between 200 and 300 ppm to prematurely appear. If more than 600 ppm is used, however, then it will have the opposite effect and will hinder flower development.

Gibberellic Acid may also stimulate growth when applied in certain areas.


Using an Auxin such as indole acetic acid (or “IAA”) helps with plant size increasing, root growth increasing, stimulating growth in general, and sometimes even increasing the growing season when applied late enough.

Auxin marijuana plant
Auxin marijuana plant

When combined with Brassinolide, this can help with cell expansion and cell elongation.

Fulvic Acid

Once the marijuana plant is established enough to be considered “adult” (likely around week two), fulvic acid can be applied to the plants. Although not a hormone in itself, it can do wonders for the transport of plant growth hormones when it is applied to the foliage of a plant. Because it permeates the cell walls, it assists with the absorption of plant hormones in general.


The most commonly used Cytokinine, Kinetin, can be applied to your plant during the vegetative phase to help with cell division, the development of new growth (such as buds, branches, and shoots), cell enlargement that leads to leaf expansion, and so on. Use a spray (such as the Bonide Tomato and Blossom Set Spray) to spray it on your plants and encourage better growth and bigger yields later.

Flowering Phase


Increase the female flower production by diluting Ethylene in water and spraying it directly on your plants. Do this before the pre-flowers appear, but towards the end of the vegetative phase. Any synthetic form of ethylene will convert to actual ethylene quite rapidly after making contact with the plant itself (such as when you use ready-to-use Ethephon or concentrated Ethephon that you diluted first).

Gibberellic Acid

This could also be applied to marijuana plants during the flowering phase to help with potential frost damage when the buds are flowering. Spray the plants with it to get this effect.

Flowering Phase
Flowering Phase

Ultimately, plenty of research still needs to be done on the use and application of plant hormones on marijuana plants. Differences in the environment, stressors, grow setup, and even the strain of the marijuana plants themselves lead to considerable alterations in the effects that these hormones may have.

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    For that reason, trial and error may be the best way to figure out for yourself which hormones work best for your particular grow situation. Just remember: plant hormones are powerful things, so keep everything in moderation because too much of one type of hormone can do more harm than good.

    Avatar for Robert Bergman

    Robert Bergman

    Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations. His passion for growing led him to develop his own Gold Leaf strain. Now, Robert is dedicated to sharing his knowledge with the world.... [Read full bio]


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