How to Clone Cannabis

Updated: May 24, 2018


Cloning creates new cannabis plants from stem cuttings instead of seeds. Roots form from broken stem tissue as a survival mechanism called vegetative propagation. Even a small clipping can regenerate itself under the right conditions. Cloning turns one mature cannabis plant into hundreds of genetically identical clones!


When cut, cannabis attempts to save itself from wilting. Roots form from the scar. A broken cannabis stem will regenerate roots and become a new plant if it can survive the stress of being cut. Therefore, vegetative propagation technique is akin to an Intensive Care Unit. With high humidity and stable environment the cutting will regenerate new roots and shoots in a about two weeks.


Clones start out small, but they are the same age as their parents. This means that clones skip the early developmental stages of the cannabis life cycle. A rooted clone is small, but it does not need months of vegetative growth to mature like a seedling would. Instead, it is physiologically able to flower as a miniature plant on day one. Or, with 18+ hours of daylight, a clone will grow as big as you want it to be.


Organize your Tools

  • Sharp, sterilized trimming scissors

  • Propagation tray and humidity dome

  • Rapid Rooter plugs

  • Hormex liquid concentrate

  • Shot glass

Prepare Grow Medium


Soak the Rapid Rooter starter plugs for a few hours prior to use to stabilize pH. Soak cubes in a solution of diluted Hormex (5ml/gal) adjusted to pH 6.0, or plain water.


Choose a Mother Plant


Cut clones from vigorous, healthy plants in the vegetative phase. Water and fertilize before taking cuttings so that the plant tissue is fortified for the cloning process. Stressed plants produce stunted clones because their growth rate is already slowed. Mother plants don’t need to be big, or old. A clone or two can even be cut from seedlings around week three or four. Just don’t remove more than 25% of foliage from the mother plant or else it will cause stress and slow growth.


Cut Clones


A clone will regenerate from any piece of stem tissue that includes meristem. Meristem is important because it is the plant tissue that can produce either roots, shoots or flowers, depending on the growth phase. You can identify meristem tissue by location, at the node (swelling/knot) above the petiole (leaf stem). An ideal clone includes the tip of a branch and is cut diagonally 2-3 nodes below the tip. Trim and remove the lowest nodes and fan leaves. Leave one or two lateral meristem intact below the tip of the branch.


Timing is critical for successful clone cutting. Prepare your workspace and make a plan so you can work with surgical precision and speed.

  1. Cut clones away from direct lights and fans.

  2. Keep the humidity high during the process.

  3. Bright lights and dry wind wilt cuttings before they make it to the propagation tray.

  4. Fill a shot glass with 15ml of Hormex-- you will dip cuttings in this as soon as you cut them.

  5. Sterilize your scissors or razor blade with 91% Isopropyl Alcohol. Wipe dry.

  6. Load the soaked starter plugs into the cells of the propagation tray with the narrow tip pointing downward, and the small hole facing up.

  7. Organize and label the tray if you are cloning multiple cannabis strains at once.

  8. Cut the stem diagonally below the node.

  9. Quickly trim off the lower lateral meristem and fan leaves.

  10. Leave 1-2 lateral meristem below the growth tip.

  11. Trim tips of fan leaves to save space (optional).

  12. Immediately place cutting in full-strength Hormex solution for 60 seconds.

  13. Transfer to the propagation tray.

  14. Gently insert the stem about ½” into the hole. Don’t force it. Use the tip of your scissors to open the hole, if necessary.

  15. Cover the propagation tray with the humidity dome while you cut the next clone.

Postoperative Care


There is no exact formula for nurturing unrooted cuttings. Usually they require more observation than action. Subtle changes may be needed in dome venting, lighting, watering and fertilizer schedules. Over-attention can hurt the plants, so think twice and act once.


Vegetative propagation works best in a 72F room with 45% humidity. Keep clones away from blowing fans and High Intensity Discharge lighting. Use a T5 cool fluorescent or LED light fixture for tender clones. Indirect air movement and fresh air exchange helps the process. If you provide a stable environment and healthy mother plants, this method should work for you:

  1. Place the humidity dome on the propagation tray with the vents completely closed

  2. Position the tray under the grow light.

  3. Partially open vents after 48 hours.

  4. On day 7, flood the tray with a 1/4 strength hydroponic solution.

  5. Drain after 5 minutes.

  6. Completely open dome vents.

  7. On days 7-14, “burp” the clones.

  8. Remove the dome for a moment to allow moisture to escape.

  9. Gradually increase the burp time until the dome is no longer used by day 14.

  10. Water as needed when the starter plugs turn light brown. Use ⅓ strength hydroponic solution.

  11. Transplant on day 15.

Variables

  • Excess condensation on the walls, combined with yellowing leaves around day 3 is a sign to increase venting and burp the plant sooner than 7 days.

  • Water sooner if the starter plugs change from dark to light brown.

  • Clones need roughly the same intensity light as their mother plant. Hang your light fixture at the same distance as the light above the mother plant. Do not use HID lighting for the clone process.

Cannabis cuttings soaking in Hormex