If you already have a well developed marijuana plant (or a friend who does), taking cuttings from it (cloning) is the quickest way to get new plants going. The clones will have identical genetics to the “mother” the cuttings came from. Cloning marijuana plants gets you a head start – for the same amount of time, clones are way ahead of plants started from seeds.
Items you need for cloning marijuana plants:
- Plant big enough to have branches cut off (we like to take clone cuttings as part of the pruning process right before putting a plant into bloom (12 hours of light, 12 hours of dark). You can take cuttings after a plant has been in bloom for a while, but the longer the mother has been in bloom, the longer the new clones will take to root and get back into “vegetative growth”.
- Clean, sharp knife, razor blade or scissors
- Rock wool block (or other, similar “rooting plug”)
- Distilled water (or water that has been pH adjusted to around 6).
- Rooting hormone powder or gel (optional but recommended)
- Humidity dome or plastic bag (optional but helpful in dry environments – around 70% humidity is ideal)
- Heat mat (optional but helpful in cooler environments, probably not needed if the air temperature is high 60’s F. 70 to 75 degrees F is ideal)
Steps to cloning marijuana plants:
- Soak a rock wool block in distilled water and place on a plate or tray (no not squeeze the water out as that will damage the rock wool).
- Choose a branch towards the bottom of the plant, and using the sharp blade, cut 45 degree angle near base of the branch. We like our clones to be 5 to 8 inches when cut.
- Scrape a bit of the outside skin or “bark” off the branch’s stem near the cut.
- Dip the 1/2” of the cut end of the branch into the rooting hormone powder or gel.
- Gently push the cut end of the branch into the rock wool block (we don’t use the hole in the block, if it has one). Push it most of the way through but not poking out the bottom, if you can. Don’t forget to label the cutting, if you’re taking more than one variety (strain).
- It’s possible to put more than one cutting into one block (the block can be torn into pieces to separate the plants after they have successfully grown roots – but you’ll have to be careful not to damage the roots when pulling or cutting the rock wool blocks apart).
- If the branch has branches, you can trim off the small branches. Also, it it has a lot of leaves, you can trim back some near the cut. Some people like to also cut the tips off of big leaves but we don’t bother.
- It’s best to take more cuttings than you think you will need (in case they don’t all survive). If they all survive and root successfully, give extra clones to your friends to help them get started.
- In dry conditions, place a dome over the cuttings to keep them from drying out too quickly. In warm, humid weather, we don’t put any sort of cover or humidity dome over the clones, or they may be too wet and grow mold.
- Put under shade or indirect light, especially for the first few days. In cooler conditions, you may want to place a heating mat (intended for starting seedlings in cool environments) under the tray.
- You can pick up the rock wool block every other day or so to check if it needs distilled water added (if it feels light like a dry block add water). You can also mist the leaves with a water sprayer if you like.
- Under ideal conditions, roots will start to grow out through the bottom of the block in about a week. Don’t worry if it takes longer (2-3 weeks can be common for some strains under some conditions). Be patient and keep waiting as long as the cutting still appears to be healthy.
- Once the roots start showing out of the bottom of the block, you can mix some nutrients into the distilled water you add to the blocks (we like mixing the nutrients “half strength”, or twice as much water to powder, as the nutrient’s directions indicate.
- Once the roots abundantly grow out of the bottom of the block, it’s ready to be transplanted into a growing container, such as a deep water culture hydroponics bucket. (Blog post coming soon).
