Root hormones for plants

10 Best Rooting Hormones in 2020

Rooting Hormone Buyer’s Guide

Many individuals enjoy looking after and cultivating their plants within their gardens and greenhouses. Plants are able to make their own rooting hormone, although it takes quite a long time. Subsequently, plants can be very easy to clone and replicate. In order to help new cuttings to grow fast and strong, many gardeners use a rooting hormone which encourages the stem to experience root development and create new plants, in addition to protecting the cutting and plant from fungus or disease.

How Does a Rooting Hormone Work?

To use a rooting hormone, you first need to take a fresh cutting from your desired plant. The cutting should have a stem of between 4 – 6-inches. Dip the last 1-inch of the stem into the rooting hormone, which may take the form of either a powder, a liquid or a gel. Next, plant the stem in a bed of moist, fresh soil. The rooting hormone replicates the natural process but enables the stem to develop faster and stronger, with additional benefits of protecting the cutting from fungus or disease.

Liquid, Powder or Gel?

Whether to use a liquid, a powder or a gel is dependent upon your preferences. Realistically, each type of formula works in the same way although there are some differences in the formula which you choose. For example, a gel-based rooting formula may be a safer choice if you have young children or pets at home, as gels are less prone to spillages.

However, a liquid rooting formula may suit some individuals as many liquid rooting hormones can be used in different ways and for different purposes, providing adaptability and value for money. The most popular choice of rooting hormone, however, is a powdered formula, perhaps because the coverage of the stem is more visible.

How Long Will a Rooting Hormone Take To Work?

To experience the full benefits, the rooting hormone may take between 3 – 5 weeks. On rare occasions, a stem cutting may not become stimulated fully by the rooting hormone, and so the cutting may eventually wilt. It may be beneficial, therefore, to develop two or three cuttings at once from the same plant, in order to ensure success.

Of course, using a rooting hormone is not compulsory as the plant naturally completes this process, albeit at a slower pace. There are also natural alternatives which may be used in the same way as a rooting hormone.

Other Uses for a Rooting Hormone

In addition to stimulating plants and providing strong and fast growth to the stem and roots, rooting hormones also provide protection against disease and fungus. It is important to ensure that cross-contamination of your plants does not occur as fungus and disease may destroy several of your plants. Some rooting hormones additionally help to prevent transplant shock when moving a plant, providing further protection for your beloved plants.

Rooting hormone is a mixture of plant hormones which are able to stimulate the growth of a plant cutting. By using a rooting hormone, you can clone a new plant from a fresh plant cutting, ensuring that the cloned plant grows fast and strong while being protected from fungus and disease.

How to use Rooting Hormone?

To use a rooting hormone, you first need to take a fresh cutting from your desired plant. The cutting should have a stem of between 4 – 6-inches. Dip the last 1-inch of the stem into the rooting hormone, which may take the form of either powder, a liquid or a gel. Next, plant the stem in a bed of moist, fresh soil.

What is in Rooting Hormone?

What ingredients your rooting hormone contains depends upon the brand and model of the rooting hormone. However, most rooting hormones in a powder, liquid or gel base will contain Indole-3-Butyric Acid as an active ingredient. Many rooting hormones will additionally contain vitamins, minerals, and nutrients although combinations will vary.

If you love your plants and want to help them to grow fast and strong then using a rooting hormone is an effective way to stimulate their growth while protecting your plants from fungus and disease. There is a wide range of rooting hormones available for you to try, ranging from traditional liquids to popular powders to modern gels. Using a rooting hormone ensures that you cultivate the beautiful plants you desire.

Alternatively, there are several different natural rooting agents available for you to try although you may receive slower results in comparison with using a rooting hormone.

Expert Tip

Where possible, always favor fresh cuttings over seeds. When using cuttings, you will be able to cultivate an exact clone of the original plant. The genetic of seeds vary and so you may grow a plant slightly different than the plant you intended to cultivate.

Did you know?

You can use cinnamon as a rooting agent. Applying to the stem of your fresh cutting stimulates root growth in most plants, encouraging the stem to produce additional stems while protecting the cutting against fungus. Simply roll the end of the stem in cinnamon powder. This is a great tip for individuals who would prefer to avoid chemical or other unnatural agents.

Furthermore, there are many other natural rooting agents easily available and which also work well on your plants. Three teaspoons of apple cider vinegar mixed with one gallon of water work great, as does honey which provides natural anti-bacterial properties. Simply add one tablespoon of honey to two cups of boiling water then leave to cool. Additionally, you can use crushed aspirin dissolved in water, or you could make willow tea from willow leaves. A controversial rooting agent which works great is saliva which acts as a natural root enhancer.

Natural Alternatives to Synthetic Rooting Hormone

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This is the Wild West of the gardening world. Or, one of many.

There is so much misleading or anecdotal advice about ‘natural’ ingredients believed to trigger root growth, but few if any have any science to back them up.

If you find any peer-reviewed studies that affirm their use for rooting cuttings, please send them along!

Personally, I just use a commercial product as needed since it’s inexpensive and works.

I’m all in favor of experimenting with propagation but not misleading new gardeners with folklore or misinformation.

Here’s a few suggestions I’ve seen mentioned in gardening forums.

They all have other good uses in this world (of course), just not for this purpose:

  • Aloe vera gel
  • Aspirin
  • Cinnamon
  • Coconut water
  • Honey | Honey is antiseptic and anti-fungal. The theory is that by dipping a cutting in honey, we’re preventing disease. I can’t find any studies to show this. My thought is, if you’re using honey, you can’t apply rooting hormone because the stem is already coated in honey. And, is the threat of disease really so great that you’d rather use the honey than rooting hormone?
  • Seaweed extract | There is evidence this can stimulate root growth both in cuttings and transplants. The trouble is finding the right product and application amount. If you want to use a seaweed product, do your homework first. There are a lot of wild claims out there.
  • Willow water | This one has been in garden folklore for years.
    Willow plants are fast-root growers but there is nothing I can find to show willow water (made by soaking willow branches in water) will create some sort of auxin-rich liquid that could induce root growth in other plants.
    For starters, the auxins (if present) would be greatly diluted and I have no idea if it would be in a form that another plant could use. So, do more research if this interests you.
    It’s nearly impossible to judge based on anecdotal evidence when there are so many other varying factors.

And that’s rooting hormone 101. Use it wisely and you’ll have lots of free new plants.

~Melissa the Empress of Dirt ♛


  • How to Take Softwood Cuttings| Spring and summer
  • How to Take Hardwood Cuttings| Fall and winter
  • Seed Starting for Beginners| Sow indoors grow outdoors

Q. How do I use Dip’N Grow for the first time?

A. Each bottle of Dip ‘N Grow comes with directions for use on the labeling. Our 2-ounce size Dip ‘N Grow Rooting Kits also come with a comprehensive directional insert.
Here is a summary of the proper use and a recommendation for users who are switching from the powder to the liquid.

a) Always read the entire directions for use and the precautionary statements on the package or bottle of Dip ‘N Grow prior to use. Dip ‘N Grow is recommended for use on most nursery stock grown from cuttings including woody ornamentals, ground covers, deciduous hardwoods, root stock and perennials.

  • For hardwood cuttings, mix 1 part Dip ‘N Grow to 5 parts water.
    For medium hardwood cuttings, mix 1 part Dip ‘N Grow to 10 parts water.
  • For softwood cuttings and succulents, mix 1 part Dip ‘N Grow to 20 parts water.
  • Simply dip the basal end of cutting (bottom of the stem), individually or in bunches into the diluted Dip ‘N Grow for 3-5 seconds. Following dipping, place cuttings into planting medium. Keep cuttings moist and warm.

b) Since cutting propagation depends on many different factors (such as climate, contaminants, condition of cutting), it is recommended to do a trial application on a few cuttings.

  • All plants respond to a range of active ingredients, so a trial application may consist of the several cuttings of the same species with different dilution ratios to see which one is the most effective for that particular plant. If in doubt of the best
    concentration, less is better than more. Try a greater dilution with water.
  • Because of the many factors involved, liability of any claim arising out of the use of the product is limited to replacement of the product or refund of the purchase price.

b) Since cutting propagation depends on many different factors (such as climate,
contaminants, condition of cutting), it is recommended to do a trial application on a few

Dip & Root Rooting Hormone

R 70.00

SKU: PRG005 Category: Plant Propagation


Dip & Root Rooting Hormone is a liquid rooting stimulator and is used extensively for the propagation of plants for ornamental use in gardens and landscaping, as well as commercially for the propagation of fruit trees.

Dip & Root is diluted with water to the required strength as follows :

Mix 1 : 20 for softwood cuttings
Mix 1 : 10 for semi-hardwood cuttings
Mix 1 : 5 for hardwood cuttings

Active Ingredients :
4-Indole-3-Butyric Acid : 10g / Lt
1-Naphty-Acetic Acid : 5g / Lt.

Size: 10ml

Dip & Root is a liquid hormone agent that can easily be diluted with water to any strength you should require. Due to the fact that it is a liquid, the right amount of hormones get in contact with the cutting, ensuring that the auxin is easily absorbed. You can even bunch your cuttings and each cutting will receive the identical treatment.

Dip & Root’s proven formula contains two rooting inducing hormones. As the solution contains alcohol, it is self sanitizing, to eliminate cross-contamination, which is very important. It is a stable solution that will not easily deteriorate with age.

By using Dip & Root all required concentrations can be obtained from one container. The ratio can be adapted to suit each type of cutting.

RootBoost™ Rooting Hormone

  • Use only on ornamental cuttings. Established plants and their roots are not affected.
  • Use a sharp, sterilized knife or pruner to take 4- to 6-inch cuttings from soft stems or new, immature woody stems. Work during the active growing season for best results on most plant types.
  • Keep cuttings protected and moist, and remove all but the top set of leaves.
  • Pour a small amount of the rooting hormone into a shallow dish. Do not mix with water.
  • Moisten the end of a cutting slightly, and then dip it into the dish, thoroughly covering the tip and at least one exposed leaf node. Tap to remove any excess.
  • Insert cutting at a slight angle into a tray of rooting medium, such as a light potting mix, perlite, sand or a commercial rooting mix designed especially for cuttings.
  • Discard any rooting hormone remaining in the shallow dish when finished. Do not return it to the original container or you risk contaminating the rest of the product.
  • Place the rooting tray inside a plastic bag or cover it with plastic to form a mini-greenhouse, and then place in indirect light.
  • Mist and water, as needed, to keep cuttings hydrated and rooting medium moist while roots grow.
  • Transplant rooted cuttings once roots establish well and new growth appears.
  • Read the product label and follow application instructions thoroughly.

Garden Tech Root Boost Root Hormone Powder

+ Read More

GardenTech RootBoost Rooting Hormone may be used on three types of cuttings.

  • Hardwood: such as Dogwood, Juniper, broadleaf and needle evergreens.
  • Semi-Hardwood: such as broadleaf evergreens and woody ornamentals with firm wood and mature leaves such as Azalea, Rhododendrons, Magnolia and Photinia.
  • Softwood and Succulents: such as Cactus, Fuchsia, Ice Plant and Begonia.

Select cuttings from healthy plants. Success is generally best when taking softwood cuttings or “new wood”. Timing is important. professionals propagate year round but two good times for taking cuttings are:

  • in the fall using mature dormant growth which would be classified as a hardwood or semi-hardwood cutting.
  • in the spring when the cuttings would be new growth or classified as a soft-wood cutting.

Fertilizer can encourage top growth and may not be used for one week after treatment.


Cuttings of the current season’s growth, 4 to 6 inches in length, generally are most satisfactory. Entire shoots of this length, cut at or near the base, should be taken, unless it is known that other parts root more readily. Some plants are readily propagated from leaf-bud cuttings. Propagators are familiar with the fact that tip cuttings of some varieties, and parts below the tip in other varieties, root best. This applies also, but to a lesser extent, to cuttings treated with GardenTech RootBoost Root Hormone. The basal cut may be made slanting or straight with small pruning shears, or with a knife. Large leafed types of cuttings will need to be trimmed, but it is preferable to use the largest leaf area which can be kept in god condition, and which at the same time meets the requirements for economy of space.


Throughout the United States, the time to take cuttings will be dependent on when new growth starts. Cuttings of the current season’s growth, 4 to 6 inches in length, generally are the most satisfactory.

Note: Cuttings of certain plants can be taken over a much wider range of time in the south that in the North, and corresponding season advance must be considered.

In the State of New York, cuttings of most deciduous shrubs will root best when taken during June, July and August. A few varieties can be taken the latter part of April, and others during May, depending upon when new growth starts. Cuttings of the current season’s groth, 4 to 6 inches in length, generally are the most satisfactory. Cuttings taken between August and December will vary considerably in their capacity to root. For plants grown indoors, cuttings should be taken according to the condition of the material, without regard to season.


Keep cutting material in a fresh condition from the start. Cuttings of many varieties keep fresh when the basal ends of the stems are immersed in water or wrapped in wet cloth or burlap until ready to place in GardenTech RootBoost Rooting Hormonee. Do not kep shoots and branches in closed containers for long periods. Frequent spraying of the cutting material, according to the dryness of the air, or covering with moist cheese cloth, will prevent excessive wilting.


After treatment with GardenTech RootBoost Rooting Hormone, plant the cuttings in a mixture of 1/4 peat moss and 3/4 sand (by volume), or in sand only, until rooted. Propagators who have a satisfactory rooting medium should continue to use it. Any method of planting cuttings which keeps them in good condition may be used. When cuttings are planted in a vertical position, they require more critical care than when slanted in such a way that the exposed leaves lie flat or close to the surface of the rooting medium. Sufficient shade must be provided at all times, but particularly on hot, bright days, to keep the cuttings fresh, but not dense enough to cause rotting of leaves, or the growth of molds. Immediately after planting, the cuttings should be watered thoroughly and, thereafter, according to climactic conditions. The rooting medium below the surface must not be allowed to become dry.

A temperature in the bed of 70 to 75 F has proved satisfactory for many species. Temperatures below 60 F are not generally satisfactory with tested cuttings.


  1. The cut ends of the cuttings should be slightly moistened before treatment.
  2. Stir cut ends in GardenTech RootBoost Rooting Hormone powder.
  3. Remove excess powder by tapping on rim of container.
  4. Plant treated cuttings in a rooting medium such as . Mist regularly.

Green Lights “RooTing” & SUPERthrive rooting comparison

For years I have been recommending” RooTing” by Green Light to customers when they would come into the store and ask for a rooting hormone. Recently I attended a Home Depot Garden Seminar. One of our vendors explained in detail more about Superthrive, a growth hormone for plants. I found out that Superthrive is also good to use as a rooting hormone as well! I thought it would be interesting to do a comparison of SUPERthrive & GreenLights “RooTing” to see if there was any noticeable difference in growth between the two products.

One Feb. 24, 2012, I took six cuttings from one of my rose bushes and soaked three in a cup & 1/2 of water with one teaspoon of “Rooting” mixed into the water and three cuttings in a cup & 1/2 of water with 4 drops of SUPERthrive. I soaked each group for 48 hours before planting them in a well-drained planting mix. After placing the cuttings into the soil, I watered the RooTing cuttings with the mix they had been soaking in and also did the same with the SUPERthrive cuttings. All the cuttings were then placed in a shady area. When doing this type of procedure, the planted cuttings should not be left out in the sun. Even though roses are full sun plants, the cuttings need the shade to lessen the stress they have already endured and begin the rooting transformation. Essentially what is happening to the cutting is that the stem is being fooled into thinking that it is a root and needs to grow roots to survive. The rooting hormones will cause this transformation.

If you are unable to get your cuttings into the rooting hormone immediately after you have cut them, be sure to have them soaking in water until you are ready start this process. When you are ready to put your cuttings into the rooting hormone, be sure to cut about ¼ inch off the bottom of each cutting before you place them into the rooting hormone mix. The bigger the cutting, the more important it is to have a fresh cut on the bottom before you begin your soak. For the smaller cuttings that are ¼ inches or smaller, you may want to try just coating each cutting in the “RooTing” powder before placing it into the planting mix or for the SUPERthrive, just watering them into the planting mix. I like to do the pre-soak to ensure success.

As of this morning March 6, 2012, I am seeing growth on all my cuttings! This past weekend was unseasonably warm and we had temperatures up into the high 70’s and 80’s on Saturday and Sunday. This may have help to spur the growth. As the weeks progress, I will be monitoring the progress of the two products to see if one out performs the other or it they both exhibit the same performance. Only time will tell.

Be sure to check back to see what results will be achieved. Check out my video to see some results that are up close and personal as well.

This has been another of,

How To Keep Herb Cuttings Alive With Rooting Hormones

When you are trying to grow herbs from cuttings, you may find that many of your cuttings don’t grow roots. They may fail to root at all, root but have yellow and sickly leaves, or die. In our last post, we wrote that you needed only water to grow cuttings, which is true, but in some cases your cuttings may need a little more help. If you aren’t seeing results, or if you are attempting to grow herbs from woodier cuttings, then you should try using rooting hormone.

What are Rooting Hormones?

Plants use hormones to grow just like humans and animals, though their hormones are different. Various hormones cause a plant to focus on roots rather than side buds, for example, or start flowering, or drop fruit. The particular hormones we are interested in here are “auxins,” the hormone that tells the plant to root. One auxin is called Indole-3-butyric acid (IBA). There are a few synthetic chemicals that replicate IBA and they are available to home gardeners in various different forms, such as powders, liquids, and gels.

Some kinds of cuttings require rooting hormone more than others. The greenness of the stem is what determines the cutting’s rooting capability. The top part of a cutting is called “softwood.” This is the part of the stem that is green and bends easily without breaking. Softwood cuttings can often root in water alone and don’t need hormone. In most herbs, your cuttings will all be softwood cuttings. Basil, milt, cilantro, lemon balm, etc. are all mostly softwood. Other herbs that grow more stiffly, like rosemary and thyme, will have stems that have already turned brown and hardened. The middle part of the stem, where the green changes to brown, is called semi-hardwood. The hardest part of the stem is called hardwood. These older parts of the stem contain less rooting hormone than the softwood part of the stem. If you take a hardwood cutting, you will definitely need to apply growth hormone.

How To Apply Rooting Hormone

Dosage is important. Too little hormone will have no effect on the plant, but too much hormone will cause the plant to yellow and wither. Just like real medicine, it’s important to get dosage right.

Tip: To prevent contamination, always remove a small amount of hormone first and put it into a separate bowl or dish. Throw away any unused powder at the end. This will prevent you from carrying over any diseases from one plant to another.

For powdered hormone, dip the end of your cutting into a shallow plate of hormone powder. Then tap the end of your cutting on the table or the edge of the plate to shake off excess powder. You should have a thin film of hormone left over on the skin of the cutting, no more than a quarter inch away from the base of the stem. You can put the cutting into a glass of water to start it, or you can plant it directly in a pot of potting medium (more on that below). If you do use a potting medium, don’t shake off the stem first. Just push the stalk firmly down into the soil. Any loose hormone will rub off into the soil, which is fine. It’s better to start out with too little than too much.

For liquid hormone, dip the end of your cutting into a cup or bowl containing the hormone. Only hold the cutting there for a second or two, not more. Too much time can cause the plant to absorb too much hormone, which may cause the leaves to yellow or burn the plant stem. Liquid hormone is powerful and the results can be better than average, but the dosage can be difficult to get right. Beginners often prefer powdered hormone instead because it is harder to make mistakes.

Rooting hormone also comes in gel form, which is the easiest to apply because it’s easier to measure dosage, and the gel tends to stay on the plant stem better than powdered hormone does. Gel works best when you are planting your cuttings in a rooting medium and not in a glass of water. Dip the cutting in a bowl of gel according to the instructions. Typically, the gel should come up about a quarter of an inch on the stem. Push the cutting directly into the rooting medium afterward. Discard any unused gel when you are finished.

With rooting hormone, you should see a better response from your cuttings than if you used water alone, especially if you have more semi-hardwood or hardwood cuttings. Rosemary and thyme, for instance, are unlikely to root in water alone, but with rooting hormone and a dry rooting medium, they can do very well.

Using a Rooting Medium (Instead of Water)

A quick note on rooting mediums. Rooting medium is not dirt or soil: in fact, it usually contains no dirt or soil at all. Instead, it is often a lighter material that is less abrasive to the plant cutting, and which tends to hold water better. Rooting mediums can be fine gardener’s sand, perlite, vermiculite, sand, sphagnum moss, and other similar materials. You can pick any of these up at a gardening store.

How does Urban Leaf do it?

Once you plant is rooted, you will be able to regrow it in to a full plant – it just needs nutrients light and water. Our bottle garden kits are loaded with nutrients and are perfect for growing your rooted cutting into a nice bushy plant!

How to Use Rooting Hormone When Propagating Plants

Juj Winn/Getty

If you want beautiful, full, diverse planters without the hefty price tag, you may consider propagating your plants. Propagation is the process of growing new plants from clippings of existing plants. While it’s a fairly simple process requiring little more than soil and sunlight, some may want to help Mother Nature along with a rooting hormone. Here’s what you need to know about the technique.


What Is Rooting Hormone?

Just as hormones regulate processes in the human body, plants have hormones that help govern their growth and development. Chemicals known as auxins inform plants when to form roots. Rooting hormone products, which are commonly sold in powder, liquid, and gel form, contain natural auxins or synthetic compounds, which can be applied to clippings to stimulate root growth during propagation.


Do Your Plants Need It?

Not exactly. Plants propagate naturally, and if given the proper conditions and care, cuttings will sprout roots using their own hormones. However, some people choose to use rooting hormones to speed up the process, or for plants that have proven difficult to propagate in the past. “It’s a personal choice,” says Nadine Kremblas, the Living Arts Lead at Pistils Nursery, a specialty plant shop in Portland, Oregon. “Rooting hormone can help yield better results, but it’s not necessary.”

Plants that easily propagate, such as most varieties of succulents, rarely need the jumpstart that a rooting hormone can deliver. However, plants that are more reluctant to root, such as citrus plants, can benefit from it.


How Do You Use Rooting Hormone?

Hormones are powerful chemicals, and if used incorrectly can kill clippings and plants. With many different concentrations of rooting hormone available, it’s important to carefully read the product’s packaging to ensure that the formula is appropriate for your plant. During propagation, rooting hormone should be applied immediately before you place your clipping in the soil.

For powdered hormones, dip the base of the cutting into the hormone, then shake gently to remove any excess. Place the cutting into moist soil, loosely covering the base. For liquid and gel hormones, first check the package to see if it’s a ready-to-go mix or a concentrate. If concentrated, dilute the product with water according to the directions. Once your hormone is ready, dip the base of your clipping into the liquid or gel, leaving submerged for only a couple seconds-too long can damage the plant. Plant the cutting as you would using a powdered hormone.

Remember that rooting hormone should be used only during propagation. Feeding a mature plant hormones can damage the root system. Rooting hormone should be stored in a cool, dark place. Check the expiration date before using, as the chemicals can break down over time.

Feeling Inspired: Martha Shows Us How to Use a Rooting Hormone in the Video Below

August 2005

Grower 101: Rooting Hormones
By Christopher Cerveny and James Gibson

Vegetatively propagated floriculture crops continue to increase in popularity because of tremendous production, marketing and garden success. Growers are able to propagate a wide variety of herbaceous plants on-site through the help of improved stock plant management techniques and propagation protocols set by industry standards and university research programs. However, moderate and difficult-to-root plant species can prevent producers from realizing their full potential as propagators. Application of auxin-based, commercially available rooting hormones may be the key to overcoming this challenge, which ultimately leads to an increase in product diversity. See Figure 1, right, for a list of species that may benefit from a rooting hormone application.

In general, the application of rooting hormones is not required for most herbaceous species. The added labor cost of application is not necessary with easy-to-root cuttings; however, propagation of moderate and difficult-to-root species with rooting hormones may enhance rooting percentages. Exogenously applied hormones also facilitate rooting where cultural practices or environmental conditions are not ideal. Examples include uneven misting, suboptimal propagation temperatures and, in some cases, reduced light levels during winter. Perhaps the situation in which rooting hormones are best utilized is in propagation of the “new and unusual.” In today’s marketplace customers are oftentimes demanding new products faster than they can be developed; the green industry is no stranger to this phenomenon. Rooting hormones can improve the visibility of temperate and tropical annual and perennial species by increasing propagation success. Common or prized woody ornamental groups such as vines, groundcovers and flowering shrubs add a multitude of new possibilities to a grower’s plant inventory.


Auxin is a plant hormone that aids in the initiation of adventitious roots. Indole acetic acid (IAA) is the naturally occurring auxin found in plants. IAA is involved in nearly every aspect of plant growth and development. Some of the processes regulated by IAA include formation of embryo in development, induction of cell division, stem and cleoptile elongation, apical dominance, induction of rooting, vascular tissue differentiation, fruit development, and tropic movements such as bending toward light. Synthetic forms of auxin are available commercially in the form of Indolebutyric acid (IBA) and napthaleneacetic acid (NAA). Commercial preference given to these synthetic compounds and less to IAA is illustrated by the large number of rooting products available containing one or both of them (see Figure 2, page 38).

Cultural Practices

Plant response to rooting hormones varies with each species, but before rooting hormones are introduced, growers should implement a few simple cultural practices to reduce the number of propagation challenges. Cuttings, whether they are grown from on-site or off-shore stock plants, should be thoroughly inspected before planting. Softwood cuttings that have an actively growing shoot tip should be selected. Tissues that are too young or too old will root more slowly than cuttings that are at the proper stage of maturity. Cuttings that are too old also tend not to branch as well as younger, softer tissue. Therefore, it is important to visually inspect the lower portion of the cutting to check for woody tissue that is brown or grayish-brown in color. Cuttings that exhibit this hardwood tissue may need to be trimmed closer to the shoot tip. Fully developed flowers on cuttings are sometimes another sign that tissue may be too old to root optimally. Mist and light levels Á should be regulated appropriately, if the propagation medium is too saturated (low oxygen) or light levels are too intense, rooting is inhibited.

Hormone Concentrations

Generally speaking, auxin- based rooting products are applied at concentrations of 500-1,500 ppm for herbaceous and softwood cuttings. In addition, rates between 1,000 and 3,000 ppm may be used for woodier tissue, but the maximum recommended concentrations are not more than 5,000 and 10,000 ppm for semi-hardwood and hardwood cuttings, respectively. When optimal treatments are applied, cuttings will tend to have the following characteristics: Basal portion of cutting shows some swelling, callus tissue forms and root initials emerge just above the cutting base.

Care should be taken with rooting hormones because over- application of some formulations can cause damage to the cutting base. Formulations dissolved in alcohol are more prone to cause burn or dehydrate plant tissue. Auxin in excessive concentrations may result in inhibition of bud development, yellowing of leaves, leaf abscission, blackening of stems and even death of cuttings. It has also been reported that misapplication to leaves may result in curling or other distortion of plant growth.


There are several accepted methods of application for growers wishing to utilize rooting hormones in their propagation practices. When dipping cutting bases into a rooting hormone, better efficiency is maintained with dipping several cuttings at once, rather than dipping them individually. It is also better to use a small portion of the hormone mixture in a separate container, away from the stock batch with frequent changes. This will minimize the potential for disease spread and cross contamination.

Powders. Auxin-based rooting hormones may be mixed with talc and applied to the base of cuttings. The cuttings are dipped in the powder, then lightly tapped to remove excess chemical. To increase adhesion of powder to cutting bases, stem tissue can be re-cut or dipped in water or alcohol before application. However, this will lead to a more rapid deterioration of the rooting hormone batch and may increase the potential for disease spread.

Powdered forms of rooting hormones are generally less effective than liquid formulations applied at the same concentration. Auxin uptake by the cutting base is often inhibited by the texture of the stem (smooth vs. rough) or immediate removal of talc from the cutting tissue when inserted into the propagation medium. However, talc-based products have the advantage of being less toxic, more sanitary than the liquid formulations and quicker and easier to apply. These factors may ultimately make powders more cost effective.

Quick-dip Solutions. Quick-dip solutions follow the same general principle of application as powders, in that they are auxin-based products mixed with a carrier (usually alcohol or water) and are applied to the base of the cutting. Cuttings are dipped for 1-5 seconds at a depth of 1?4 to 3?4 inches. Dipping the cuttings deeper in solution can be used to compensate for lower auxin concentrations.

Quick-dip solutions have the advantage of being highly uniform, consistent and easy to use. However, the risk of disease contamination is higher with liquid formulations. These formulations also tend to increase in auxin concentration as the solution evaporates. It is important to change out solutions periodically throughout the day, especially in hot, dry environments, and to keep containers tightly sealed when not in use. It is also a good idea to throw out any unused solution at the end of the planting period rather than putting it back into the stock container.

Other formulations. Water soluble formulations of rooting hormones such as K+ or potassium salt formulations of IBA and NAA have traditionally been used by propagators of woody ornamentals and show promise for herbaceous plant propagation. These compounds are readily dissolved in water rather than alcohol, which tends to make their use by growers safer and easier.

Post-planting sprays. As an alternative to dipping cuttings in talc or liquid, rooting hormones can be applied to cutting bases or the foliage as a spray. Pre-plant foliar sprays directed toward the stem base can be applied with a spray bottle; this is most practical when applied to bundles of cuttings before planting. This form of application eliminates the need of a common container, ultimately reducing the incidence of disease spread. With post-planting applications of rooting hormones (spray to the point of run-off), much lower concentrations (50-100 ppm) of auxin are required when compared to conventional methods. Advantages to this treatment are that fewer workers handle the chemicals, and applications can be made up to 24 hours after planting. One challenge to this alternative method of application is that limited information on rates and concentrations for specific crops is available.

From a practical standpoint, most of the plant species used by the greenhouse industry root relatively easy. The propagation process can often be hastened by treating cuttings with commercially available rooting hormones. Improved cutting performance and greater finished plant quality can be achieved with these tools; growers have to debate the added expense of hormone application and cost versus increased product diversity and the potential for increased revenue.

Christopher Cerveny and James Gibson

Christopher Cerveny is a graduate research assistant and James Gibson is assistant professor in floriculture at the University of Florida-Milton. They can be reached by phone at (850) 983-5216 or E-mail at

Root Stimulating Hormone: How To Use Rooting Hormones For Plant Cuttings

One way to create a new plant identical to the parent plant is to take a piece of the plant, known as a cutting, and grow another plant. Popular ways to make new plants is from root cuttings, stem cutting and leaf cuttings—often using a root hormone. So what is rooting hormone? Keep reading to find out this answer as well as how to use rooting hormones.

What is Rooting Hormone?

When propagating plants using a stem cutting, it is often helpful to use a root-stimulating hormone. Rooting hormone will increase the chance of successful plant rooting in most cases. When rooting hormones are used, the root will generally develop quickly and be of higher quality than when plant-rooting hormones are not used.

While there are many plants that root freely on their own, using a root hormone makes the task of propagating difficult plants much easier. Some plants, such as ivy, will even form roots in water, but these roots are never as strong as those that are rooted in soil using a rooting hormone.

Where Can You Buy Root Hormone?

Plant rooting hormones come in a few different forms; the powdered is the easiest to work with. All types of rooting hormones are available from online garden sites or at most garden supply stores.

How to Use Rooting Hormones

Successful propagation always begins with a fresh and clean cut. Remove leaves from your cutting before starting the rooting process. Place a little bit of the rooting hormone in a clean container.

Never dip the cutting into the rooting hormone container; always put some into a separate container. This keeps the unused rooting hormone from becoming contaminated. Insert the cutting stem about an inch into the root-stimulating hormone. The new roots will form from this area.

Prepare a pot with moist planting medium and plant the dipped stem cutting into the pot. Cover the pot with a clear plastic bag. The new planting should be placed in a sunny location where it will receive filtered light.

While waiting for new root growth, be sure to keep the stem cutting moist and watch for new leaves to form. When new leaves appear, it is a favorable sign that new roots have formed. The plastic bag can be removed at this time.

As your plant matures, you can begin caring for it as a new plant.

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