Rooting Stubborn Marijuana Takes Practice
Some stubborn marijuana plants may seem to resist all your attempts to clone them. This can be frustrating, particularly for breeders who use a lot of clones or who are accustomed to having easy success with their cloning techniques. Before you tear your hair out, though, just accept that some strains just give you a hard time, but they can be tamed.
One popular method of rooting stubborn clones is to use the good old-fashion potato graft. To use the potato graft, simply prepare your trimming as you usually would. Select a potato that has at least 2 or 3 eyes, and carve a small hole in it for the cutting. Once you’ve prepared it properly and used the rooting hormone of your choice, insert your cutting into the potato and plant as normal.
The potato graft will keep your cutting moist, and provide it with necessary nutrients to encourage root growth. As your plant grows, the potato will either be used up entirely or may start to grow itself. If you notice potato leaves growing around the base of your cannabis plant, simply trim them away.
Potato grafting also works with older, harder or generally woodier stems and stalks. To root a woodier, harder stalk, you should cut it at roughly 45 degrees and also scrape away the outer bark / skin of the cutting for about ½ inch of the stem. This will expose more of the inner bark (where the cells for root growth are located) to the rooting hormone and soil.
Another method for harder-to-root clones is known as air layering. It requires a bit more finesse and some practice, but the results are that when you take your clone from your plant, it will literally already be a plant on its own, complete with roots and ready for planting.
To develop roots via air layering, select the limb you wish to clone. Choose a spot under a node, just like you would for regular cutting, and prepare the intended root-site by using a sterile razor blade or another suitable sharp object to carefully cut the outer layer of bark off a ½ – 1 inch section of the branch. The goal here is to remove the outer layer of bark, known as the phloem, without damaging the inner layer of bark known as the xylem.
You can also scrape the outer bark away, but scraping is more likely to cause damage to the inner bark, including the xylem and the inner cambium where the roots will grow from. Once the root-site is prepared, apply your rooting aid of choice and then attach a rock wool cube, or secure a pocket or soil or peat moss around the wound site. Keep your rooting area moist and breathable, and roots should form within 1 – 2 weeks at which time you can cut the new clone from the mother plant and put it directly into soil for further growth.