Grafting cannabis in the gardening sense simply means taking a donor cutting (limb) from one plant, which is called a Scion. Then attaching this donor limb/Scion to another plant known as the Rootstock. In theory utilizing the grafting technique, we gain the ability to have multiple strains growing off of one mother plant. This of course opens up the grower’s world to more choices strain wise, whilst also keeping your plant numbers under any required levels.
Basic equipment required for grafting cannabis
- Scalpel or razor blade
- PTFE Tape/Plumbers tape (Its clean, malleable and creates a perfect seal)
- Clear sticky tape for first off Graft alignment (optional)
- Plastic sealing bags (Humidity tents)
- Garden wire (Plastic coated)
- Glass of water
How to graft cannabis
So firstly, you want to choose healthy plants to select your donor Scions from and then match these to a healthy and vibrantly growing rootstock. You can even use a male Rootstock if you so desire. Now once you’ve selected these you want to look for branching on both plants that have similar structure and girth. This is important as were trying to match up the different tissue levels within both graft and stock. These selected branches of similar structure become your chosen grafting pairings. Then pick your method/style of graft. I’ve experimented with both common ways of cutting the graft point and believe the slanting single cut (Whip Graft) approach to be the best for simplicity and speed.
The other method (Cleft Graft) is to cut a V into your stock and a pointed V ending to your corresponding donor, then fit together and bind. To me this takes time and a very steady hand and can cause the graft point to start drying out.
Now please make sure both donor Scion and Rootstock are both watered plentifully at least an hour before you attempt any grafting. Then get your equipment ready and close to hand. I personally prepare my new razor blade by running it through some spare cannabis plant matter, this to me is far better than cleaning with a substance alien to your plants! Then pre-cut your sections of tape get your glass of water handy and get ready to start the process. Using the Whip graft technique speed is key, as simply put, the less time you have either point of the graft exposed to the air, the better! Also for the best suited grafting sections, I try to use the straight part of the branching space between each node.
So we prepare the donor Scion by stripping away any excess foliage along its length and only leave a small amount of foliage at its growing tip, you also trim these leaves just as you would when in preparation of a Clone. With the cut itself just try and make its gradient, or angle as gradual as you can, (giving more surface area to the graft point). We cut the donor section first, as we then submerge this in water whilst preparing the rootstock side of the graft. The Rootstock side we just repeat the same process on an opposing angle to Scion’s cut, paying special attention in trying to match the angle and length up as best you can.
Then as quickly as possible, match the donor and stock graft points up, taking special note of the internal tissue layering.
Once you have the best fit, give a firm squeeze. This should help the freshly cut ends weep slightly and this helps expel any water from the join and aids in the bonding. Then firmly bind up the graft point with the plumber’s tape (PTFE). To do this, firstly secure your Graft in place as best as you can with one section of tape. Then drape another piece of tape across this same point, with the Graft running through the middle of its length. Then using a crisscross lacing motion, working under and over, your able to then pull the tape against itself, helping to form a very tight bonded seal against both light and air. (This PTFE tape is to be removed carefully a couple of days after you know you have a successful graft.) Then I also take a small piece of gardening wire and wrap this around the graft point forming a short coil. This will aid in meshing your graft point together as the section grows against the wire creating a stronger bond, (this is to be removed later once its properly established). Then lastly, for keeping your Scion donor cuts hydrated, just sprinkle a touch of your water into your plastic self-sealing bag, then cover the grafted limb with your humidity bag and seal it up nearly all the way. (leaving a small gap for the cut to breath)
Grafting cannabis requires your lighting schedule to be set on 24/7 lights on, at least until you observe new growth from the Scion. Otherwise graft attempts wilt whilst lights are out and die. As for humidity and temperatures, your normal levels should be just fine.
We have to take into consideration the point that grafting or bonding of two separate plants takes time, so the turnaround between attempts can be quite slow. This itself causes issues and means grafting to smaller young cannabis plants is probably more beneficial than working with a larger plant from the start. I’ve already successfully grafted to younger plants meaning the ability to produce a small mother plant with multiple strains is indeed possible. The Grafting process may take up to 2 weeks for a limb to fully take. This in my mind is far too long to observe and possibly still fail. So I pay attention, keeping my eye out for wilting of the donor Scion. If the grafted section wilts too much immediately or doesn’t bounce back by the third day and look perky again, then to me it’s just not going to happen, so I simply remove the attempt, cut back the same stock branch slightly and go again!
I’ve now had a good number of successes with this process and honestly believe my above approach to be an efficient one for the home gardener.
Final thoughts on cannabis grafting
Grafting cannabis attempts obviously carry several variables, so not every attempt is going to be a success. Though with some practice, a success rate of around 80% can easily be achieved. Grafting as a process within the Cannabis world is clearly most suited towards generating a singular mother plant for cloning multiple strains off. Yet you could also use this method for the ability to create your own strain crosses/seeds on mass in a small area. Through simple pollination of all the strains off your one multiple mother plant. The flowering of a multiple strained plant will of course entail its own set of issues, mainly due to the differing nutrient requirements of all the separate strains.