Cannabis enthusiast and student of the art of solventless extraction
Grafting is a technique used in plant cultivation to join two plants together so that they grow as one. The upper part of the plant, called the scion, is joined to the root system of the lower plant, called the rootstock. The scion provides the predominant characteristics of the desired crop, while the rootstock provides the root system and support.
A common practice in commercial agriculture, grafting is used to produce fruit trees and ornamental plants with desired characteristics. It is also used by home gardeners to produce unique and interesting plants, by joining two separate plants together to create a single plant.
But can grafting work with cannabis?
Grafting is a valuable tool for plant growers, and it can be used to produce plants with desired characteristics and improved performance. With grafting as a means of propagation, just like cloning, each scion will preserve the exact same genetics of its mother.
Grafting gives cannabis growers precision control over the resin that a root stock will produce. It’s even possible to grow multiple cultivars that offer a variety of resins, from a single mother plant. Incredible!
However, grafting is not quite as easy as cloning, or taking cuttings from a mother plant and rooting them in a growing medium. We have records of grafting in ancient China and Mesopotamia, but even modern science hasn’t offered a fool-proof process. After all this time, grafting is still tricky.
When To Use Grafting for Cannabis Cultivation
Despite the complexity involved and the horticultural expertise it requires, grafting can still be totally worth the trouble. So when do growers generally use the grafting technique?
Rooting Stubborn Cultivars
For cuttings that have difficulty rooting, grafting may be just the technique you need. Rather than risking loss of stubborn cuttings that just don’t seem to take root in a growing medium, growers can propagate those genetics through piggy-backing off an existing, thriving root system.
Salvage Damaged Plants
This can be especially useful in outdoor gardens, where mother nature and the elements can ravage plants with merciless abandon. Consider the situation where a tree branch falls onto a cannabis plant, and mortally wounds the stalk just above the soil line. Growers can plant seedlings around the damaged plant, then graft them onto the existing plant which still has a robust and healthy root mass.
Testing New Cultivars
How about growing multiple cultivars from a single plant? Grafting opens up entirely new horizons for testing new genetics. Grafting a cutting onto a rootstock provides the grower with a shortcut to sampling the resin that the cutting will produce. Rather than going through the whole process of rooting and developing a cutting, growers can graft the sample onto a rootstock and harvest the resin faster than with the traditional cloning method.
How To Select the Right Cultivars to Graft Together
Since all cannabis cultivars come from the same plant family, they are all compatible with each other for grafting purposes. So you really can’t go wrong! That said, there is one major consideration that will optimize your results, and that is flowering times. The length of the bloom cycle is one key factor to bear in mind.
Grafting cultivars together that have similar bloom times will yield the best results.
If growers graft together two cultivars with vastly different bloom times, there’s a risk of nutrient deficiency. Since plants utilize nutrients in varying amounts depending on their stage of growth, both cultivars should enter those various phases of growth together. A mismatch could lead to a nutrient deficiency and resulting decline in resin output and quality.
Tools for Grafting Cannabis Plants
- Clean razor blade
- Gardening shears
- Grafting tape
- Extra large ziplock bags
- Gardening wire
- Glass of RO Water
- Clean cutting board
- Spray bottle filled with vegetative nutrient solution (adjusted to pH 6)
How To Graft Cannabis Plants
There are several different approaches to grafting plants, but the whip and tongue technique is most ideal for cannabis. Whip and tongue is a simple and effective technique that is commonly used for fruit trees. Let’s get into it!
1. Select a scion from a healthy cannabis plant (similar to what you would be cutting for taking a regular clone), as well as a spot on a thriving rootstock. Ensure the width of your scion and the rootstock are similar, which greatly improves your chances of a successful outcome. Only use plants in the vegetative phase of growth for grafting.
2. After you’ve selected a scion and compatible section of your rootstock, it’s time to prepare both parts of the new limb (but don’t cut the scion away yet!). Remove most of the foliage on the scion, leaving behind only a few leaves at the tip of the limb. Do the same on the rootstock, removing most of the foliage below the site at which you’ll attach the scion.
3. Cut the scion away from the donor plant. With the garden shears, take the branch from the plant. Quickly lay it onto a clean cutting board. Then, use the razor to make a diagonal cut along the base of the scion. This creates more surface area for the scion and rootstock to bind together. After making this cut, place the scion into a glass of water. Time is of the essence. The goal is to minimize the scion’s exposure to air.
4. Next, we’re going to prepare the rootstock. Having already removed all the foliage from the graft site, take the garden shears and snip the branch slightly above the graft site. Then, use the razor blade to cut diagonally in a way that matches the one on your scion. Aim to make the cuts as identical as possible, which increases the odds of a successful graft. Then, quickly move on to step 5.
5. After cutting the rootstock, move quickly to attach the scion. Remove the scion from the glass of water and spray both the cut on the scion and rootstock with the nutrient solution. Match up the cuts, paying extra attention to the exposed tissue inside the branch. Matching the branches as closely as possible will help the plants bond and grow together quickly. If the cuts don’t match, quickly return the scion to the water, adjust the cut on the rootstock, and try again.
6. Once the scion and rootstock are matched properly, press them together firmly and tape them in place using the grafting tape. Use a smaller piece of tape to hold the branches together initially. Then, reinforce with more tape wrapped tightly around the cut several times. This blocks both light and air from the cuts and allows the scion and rootstock to bond properly. But it’s not a permanent fix. Be sure to remove the tape a couple of days after it appears the graft has been successful.
7. Use the gardening wire to reinforce the grafting site further. Secure the wire in a criss-cross pattern across the graft, running from slightly below the cut to just a bit above the graft site.
8. After the scion and rootstock are firmly bound together, spray some solution inside the plastic bag and place it over the new branch. Close the seal of the bag almost completely, leaving just enough open so that the branch can breathe. This plastic covering helps create the moisture-rich environment for propagation. Avoid contact between the leaves on the scion and the plastic bag, as this can invite microbial growth.
After a few days, the scion and rootstock should bind together and the plant will grow as one. Remove the plastic bag, wire, and tape. Congratulations, your graft is complete!
Grafting is a relatively straightforward process, but it does require some skill and practice. A valuable technique for the cannabis cultivator to master, grafting is great for rooting stubborn cultivars, saving damaged plants, and testing new genetics. Once you get the hang of it, grafting can serve you well in certain situations where simply taking cuttings or using tissue culture propagation falls short.
Remember to graft cultivars that both share a similar length of bloom cycle. Similar bloom cycles will guard against nutrient deficiencies that can happen if the scion requires a different feeding schedule than the rootstock.
Have you ever tried grafting? Let us know in the comments!
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FREQUENTLY ASKED QUESTIONS
What is grafting cannabis?
Grafting cannabis is a way to join two separate plants into one, by fusing a branch, or scion, from one plant with the stalk, or rootstock, of another.
Is grafting better than cloning?
Grafting is not necessarily better than cloning, but it can serve a unique purpose in situations where cloning may not be ideal. For example, grafting offers a solution to root stubborn cultivars, repair damaged plants, and test various cultivars.
Is it hard to graft cannabis plants?
Grafting can be tricky, but it’s relatively straightforward. Like many aspects of cultivating cannabis, with practice and experience anyone can master this technique.
What is the purpose of grafting cannabis plants?
Grafting can serve several purposes in cannabis cultivation, including rooting stubborn cultivars, repairing damaged plants, and testing various cultivars.
What are the best cannabis cultivars to graft together?
Any cannabis cultivars can be grafted together (since all cannabis comes from the same plant family), but it’s ideal to graft cultivars that complete their blooming cycle in the same length of time.