Whether you’re an experienced green thumb or a newbie gardener, there’s always something new to learn.
If you’ve been looking to sprout new plants from existing plants, you may have come across the term rooting hormones. But what exactly are rooting hormones?
Rooting hormones are used to speed up the growth of cuttings from plants. They are available in gel, liquid, powder, and spray form. Most rooting hormones use a synthetic formula with plant growth hormones. You can also make rooting agents with cinnamon, aloe vera, honey, willow, aspirin, and more.
In this guide, we discuss the different kinds of rooting hormones and their uses. We also discuss how you can make rooting hormones and what you can use as natural alternatives.
By the time you finish reading, you’ll be an expert!
Table of Contents
What Are Rooting Hormones?
Rooting hormones are used when you want to make a new plant from the cutting of an old plant.
This process is called propagation. Because the new plant is grown from the old plant, it has the same DNA.
The new plants need some assistance to start growing. Because they are not seeds or seedlings, they may need help to grow. Rooting hormones speed up this process by helping the roots of the new plants to grow faster and stronger.
Rooting hormones are a synthetic form of a natural hormone called auxin. Auxin is made of indole acetic acid (IAA). Many commercial rooting hormones use a synthetic imitation of this natural hormone.
The synthetic hormones contain either indolebutyric acid (IBA) or naphthaleneacetic acid (NAA). Some formulas contain both acids.
What Are the Different Kinds of Rooting Hormones?
Rooting hormones come in different forms:
- Liquid rooting hormones
- Powder rooting hormones
- Gel rooting hormones
- Spray rooting hormones
Each form of rooting hormone has advantages and disadvantages.
Liquid Rooting Hormones
Liquid rooting hormones are either pre-mixed or in a concentrated form. They are usually in a quick-dip solution, where you place the roots of the new cutting into the liquid for a specified amount of time.
The liquid form has a high absorption rate of hormones. It is also easy to use. However, there is a higher risk of cross-contamination and the spread of disease. You also need to take extra care to store liquid rooting hormones correctly. You must keep them sealed and in a cool, dry place.
Powder Rooting Hormones
Powder rooting hormones are not as effective as their liquid counterparts. Even if they have the same concentration of hormones, the texture of the stem does not allow the plant to absorb them as easily.
However, many people prefer the powder form because it is simple. The packet has a long shelf-life, it is less toxic and more sanitary, and it is easy to apply the powder.
Gel Rooting Hormones
Gel rooting hormones are usually pre-mixed. They come in a gel format that you apply directly to the plant cutting. They are a good option because they create a thick coating that does not wash off with water.
However, the thick coating of gel can prevent the cutting from getting enough oxygen. This means the cutting can wilt or even rot. You need to be careful not to cover the whole base of the plant cutting.
Spray Rooting Hormones
Spray rooting hormones come in a spray bottle. You apply them directly to the stems of the plants. This is an advantage because there is no danger of contamination or the spread of disease.
However, these rooting hormones are less common. Therefore, there is less information on the correct concentration of the hormones in the spray. This makes it more experimental and could potentially harm your plants.
What Are the Advantages of Rooting Hormones?
There are many advantages of rooting hormones.
They are an essential tool for propagation because they speed up growth and improve the uniformity of roots. This allows the plant to get all the nutrients it needs to grow and survive.
Rooting Hormones Speed Up Growth
Rooting hormones contain synthetic versions of the IAA hormone, which is naturally in plants.
These hormones promote growth by:
- Starting the process of cell division
- Lengthening stems and shoots
- Accelerating the growth of fruits
- Promoting the growth of the main stem
- Promoting the growth of vascular plant tissue
When applied to roots, the hormones increase the likelihood that the new cutting will grow faster and stronger.
Some plants do not need rooting hormone to establish new roots. However, there are many species that struggle to make new roots without it.
Rooting hormones are essential for the following kinds of plants:
It is rare that cuttings of these plants will take root without the assistance of rooting hormones. The hormones are also beneficial for many other kinds of plants.
Rooting Hormones Improve the Uniformity of Roots
As well as making cutting roots grow faster, rooting hormones also make more roots grow, and make those roots grow to the same length.
This is beneficial because plants use their roots for healthy growth. Roots suck up water and nutrients from the soil, which the plant uses to grow. They also serve as a physical anchor that stops the plant from destabilizing.
The more roots that a plant has, the more it can access the nutrients that it needs to survive. Uniformity of the roots allows for balanced growth. It is also an advantage if you are growing commercial crops that you need to harvest at the same time for the greatest profit.
What are the Disadvantages of Rooting Hormones?
Rooting hormones have some disadvantages, especially if used incorrectly.
Excessive dosages can burn plants and change their color. Contamination of the hormone solution can also be dangerous because it provides an opportunity for the spread of disease.
Rooting Hormones Can Burn Plant Stems
You need to be careful that you use the correct dosage of rooting hormones with your cuttings. Otherwise, you run the risk of burning the stems.
As a general guide, you should use the following concentrations of growth hormones for plant cuttings:
- Herbaceous/softwood cuttings: 500-1500 ppm
- Woody cuttings: 1000-3000 ppm
- Semi-hardwood cuttings: Maximum 5000 ppm
- Hardwood cuttings: Maximum 10,000 ppm
Using too much rooting hormone is dangerous because it can damage and dehydrate the cuttings.
This is dangerous because it can:
- Stops buds from developing
- Make the leaves turn yellow
- Make the leaves drop,
- Make the stems turn black
- Kill the cutting
If you buy commercial rooting hormones, you should always check the instructions on the packaging. They should advise on the correct concentrations for your particular plants.
Rooting Hormones Can Spread Disease
If you are using liquid rooting hormones, you run the risk of exposing your cuttings to disease. This is especially true if you use the same liquid for multiple cuttings from different species.
If one of your plants is carrying a bacterial infection or other disease, this can quickly transfer to your other cuttings and infect them. This can become a large problem that can infect most of your garden.
You can avoid the risk of cross-contamination by using rooting hormones in a powder or spray form. If you choose to use the liquid form, you should use different containers for different plants. Take care to store it correctly so that external particles can’t get into the liquid.
How Do You Make Rooting Hormones?
There are many excellent pre-made rooting hormones on the market.
We recommend the HydroDynamics Clonex Rooting Gel. If you prefer not to buy a product, you have the choice to make your own solution from natural alternatives.
What Are Natural Rooting Hormones?
Let’s take a look at the alternatives to store-bought rooting hormones.
- Aloe vera
- Apple cider vinegar
We will explain how each of these alternatives works as a rooting hormone. We will also explain how to make a rooting solution from them.
Cinnamon is a common household spice that you can use in desserts. It also has excellent properties as a rooting agent. It helps cuttings to produce more stems. It is also an excellent pest-deterrent and natural fungicide.
To use cinnamon as a rooting agent, sprinkle it into a paper towel. Wet your cuttings and roll their exposed stems around in the cinnamon powder. Plant them in soil immediately after application.
Aloe vera is a common succulent that produces a cooling gel inside of its leaves. It can also promote growth in other plants, including cuttings. Aloe vera can increase the number of roots and the length of the roots.
To use aloe vera as a rooting agent, extract the gel from the fresh leaves. Dip your cuttings into the gel so that they have an even covering. Plant them straight after.
Honey is a delicious natural sweetener that many people have in their kitchen cupboard. It also acts as an excellent antibacterial and antifungal rooting agent. Make sure to use pure and unprocessed honey to get the full benefits.
To use honey as a rooting agent, mix a tablespoon into boiling hot water. Allow the honey solution to cool and then dip your cuttings into the mixture. Transfer the cuttings to soil and plant them.
Willow water is made from the willow tree. The method creating willow water retains the plant growth hormones that help roots to grow.
To make willow water, you need fresh willow twigs or branches from a willow tree. Collect approximately two cups and remove any leaves. Add them to boiling water and leave them to soak for two days.
After two days, use a sieve to separate the water from the twigs. Throw out the twigs and keep the water. You can dip your cutting roots directly in the water and then plant them.
Apple Cider Vinegar
Apple cider vinegar is made from fermented apple juice. It has many health benefits for people, including acting as an antibacterial, lowering blood sugar levels, and helping with weight loss. It is also a natural alternative to synthetic rooting hormones.
You need to be careful when you use apple cider vinegar as a rooting agent. This is because large quantities can actually prevent rooting and kill your plants. Add one teaspoon to 6 cups of water and combine it well. Dip the cuttings directly into this solution and then into the planting soil.
Aspirin is a common medication that many people use for pain relief. It can also help your plants to grow and resist bacteria.
This is because aspirin is a synthetic version of salicylic acid. This acid naturally occurs in plants and helps them to grow. It communicates with the cells in cuttings and helps them resist rot and grow faster.
When using aspirin as a rooting agent, you must use the pills without coating. Crush one pill fully with a pill crusher, mortar, and pestle. Once it is in powder form, you can dip damp cuttings directly in the powder. Plant them straight after.
Saliva is the easiest rooting agent that you can use because it’s inside your mouth! It may sound unlikely, but saliva contains enzymes that can help plants to grow. A 2012 study found that animal saliva can cause plants to increase their number of buds, biomass, and stems in grass plants.
The effects are seen to be stronger in the saliva of animals that naturally eat plants (herbivores). However, human saliva is still a go-to for many organic gardeners.
To use saliva as a rooting agent, spit on a plate or in a bowl. Cover your cuttings in the spit and then plant them in soil.
How to Use Rooting Hormones
Whether you are using commercial rooting hormones or making an organic alternative, you need to follow the same process for applying the solution. This process changes depending on whether you are using stem, leaf, or root cuttings.
In general, you should follow these tips with all kinds of plant cuttings:
- Do not propagate in direct sun.
- Keep your potting medium moist but do not saturate it.
- Do not take cuttings from blooming plants while they are in bloom.
- Be patient because the propagation process can take a long time.
- Cut your stem. Use a sharp knife or shears to cut a healthy stem from the original plant. The tip should be between 3 and 8 inches (7.6 and 20.3cm) in length. You should make the cut near a node (swollen bump) in the stem and remove any leaves or flowers.
- Wet the cutting. Dip the bottom of your cutting in clean water. This allows the rooting hormone to stick.
- Dip the cutting in the rooting agent. Cover the bottom section of the cutting in the rooting agent. Make sure that you do not cross-contaminate between cuttings because it can spread disease. Shake the cutting lightly to remove any excess.
- Plant the cutting. Use a potting medium without soil, like bark. Create a hole for the cutting, place it inside, and push down to remove any trapped air.
- Water the cutting. Use enough water to make the soil medium damp but not wet. Keep the cutting away from direct sunlight while it grows.
You may need to use leaf cuttings with plants like succulents. This is because they don’t have stems, so you will need to grow directly from the leaf.
Follow the same steps as with a stem cutting, but you will need to apply the rooting hormone to the inner side of the leaf. This is the part that was growing closest to the center of the plant.
When you plant the leaf cutting, you have two options. You can plant half of the leaf in the potting mix and leaf half exposed. If the leaf can’t stand up, you may need to cover the back of the leaf in the rooting hormone and plant it flat on the potting mix.
Root cuttings are a popular option in fall. It lets the plant grow fully and bloom in spring. They are cuttings taken from the root of the original plant.
With root cuttings, you should use 2 inches (5cm) of the original plant’s roots. You will need to wet them and roll them in the rooting agent. When you plant them in the potting mix, don’t go too deep. Take care not to overwater or expose them to too much sun.
In conclusion, rooting hormones are essential when creating new seedlings from plant cuttings.
They are beneficial with difficult plants that struggle to form their own roots. The hormones speed up the growth and also increase the quantity of roots.
However, you need to be careful with concentrations of the hormones. If you use too much, you can damage and even kill your plants. You must also keep sanitary conditions to avoid cross-contamination.
Most commercial rooting hormone products include synthetic hormones. However, you can create your own with common household products like honey and aspirin.
Overall, rooting hormones of any kind are an excellent tool for any gardener. Happy gardening!