Cloning Step by Step

Marijuana Horticulture

by Jorge Cervantes

Step 1

Choose a mother plant that is at least two months old. Some varieties give great clones even when pumped up with hydroponics and fertilizer. If a variety is difficult to clone, each the soil with two gallons of water for each gallon of soil every morning for a week before taking clones. Drainage must be good. Or mist leaves heavily with plain water every morning. Both practices hep wash out nitrogen. Do not add fertilizer.

Step 2

With a sharp blade, make a 45-degree cut across firm, healthy 0.125-0.25 inch wide branches, two to four inches in length. Take care not to smash the end of the stem when making the cut. Trim off two or three sets of leaves and growth nodes so the stem can fit into the soil. There should be at least two sets of leaves above the soil line and one or two sets of trimmed nodes below ground. When cutting, make the slice halfway between the sets of nodes. Immediately place the cut end in water. Store cut cones in water while making more clones.

Step 3

Rockwool and Oasis root cubes are convenient and easy t maintain and transplant. Fill small containers or nursery flats with coarse, washed sand, fine vermiculite, soilless mix, or, if nothing else is available, fine potting soil. Saturate the substrate with water. Use an unsharpened pencil, shop stick, nail, etc., to make a hole in the rooting medium – a one half inch from the bottom of the container to allow for root growth. Place a tray containing rooting cubes r plugs into a standard nursery rooting fat. If none exist, make holes through three-fourths of the cube for clone stems. Fill rockwool tray with water, pH 5-6. Always use strong plastic trays.

Step 4

Use a rooting hormone, and mix just before using. For liquids, use the dilution ration for softwood cuttings. Swirl each cutting in the hormone solution for 5-15 seconds. Place the cuttings in the hole in the rooting medium. Pack rooting medium gently around the stem. Gel and powder root hormones require no mixing. Dip stems in gels as per instructions or roll the stem in the powder. When planting, take special care to keep a solid layer of hormone gel or powder around the stem when gently packing soil into place.

Step 5

Lightly water until the surface is evenly moist. Keep cuttings moist at all times. Clones have no roots to bring water to eaves. Water arrives from leaves and the cut stem until roots can supply it. Water as needed to keep growing medium evenly moist. Do not let it get soggy.

Step 6

Clones root faster with 18-24 hours of fluorescent light. If clones must be placed under an HID, set them on the perimeter of the garden so they receive less intense light; or shade them with a cloth or screen. A fluorescent tube six inches above clones or a 400-watt metal halide 4-6 feet away supplies the perfect amount of light for clones to root. Cool white fluorescents are excellent for rooting.

Step 7

Clones root faster when the humidity levels are 95-100 percent the first two days and gradually reduced to 80-85 percent during the following week. A humidity tent will hep keep humidity high. Construct the tent out of plastic bags, rigid plastic, or glass. Remember to leave openings for air to flow in and out so little clones can breathe. If practical, mist clones several times a day as an alternative to the humidity tent. Remove any slick, rotting, or dead foliage. Cut leaves in half to lower transpiration surface and to keep them from overlapping. Moisture that could foster fungus is often trapped between overlapping leaves. Keep the grow medium evenly moist so there is enough moisture to prevent cut leaves from bleeding out plant sugars that attract diseases.

Step 8

Clones root faster when the growing medium is a few degrees warmer than the ambient air temperature. A warmer substrate increases underground chemical activity, and lower air temperature slows transpiration. For best results, keep the rooting medium at 75-80F. Growing medium temperatures above 85F will cause damage. Keep the air temperature 5-10F cooler than the substrate. A warmer growing medium coupled with cooler ambient temperature slows diseases and conserves moisture. Misting clones with water also cools foliage and slows transpiration to help traumatized clones retain moisture unavailable from nonexistent roots. Put clones in a warm place to adjust air temperature and use a heat pad, heating cables, or an incandescent light bulb below rooting cuttings.

Step 9

Some cuttings may wilt but regain rigidity in a few days. Clones should look close to normal by the end of the week. Cuttings that are still wilted after seven days may root so slowly that they never catch up with others. Cull them out, or put them back into the cloning chamber to grow more roots.

Step 10

In one to three weeks, cuttings would be rooted. Signals they have rooted include yellow leaf tips, roots growing out drain holes, and vertical growth of the clones. To check for root growth in flats or pots, carefully remove the root ball and clone to see if it has good root development. For best results, do not transplant clones until a dense root system is growing out the side and bottom of rooting cubes.

Cuttings are always strong and healthy-looking after you take them. After five of six days, leaves may start to change color. Leaves stay small and often turn a deeper shade of green. After about a week, lower leaves may start to yellow if their nutrient levels dissipate.

A week after being taken, clones’ stems will develop stubby callused roots called primordial. The primordial are semi-transparent to white and should look healthy. Clones produce very little green growth during this process. Once the rot and vascular transport system is in place and working properly, clones are able to experience explosive growth with proper care.

Rooting clones can handle increasingly more light as roots grow. Move the fluorescent lamps to two to four inches above plants when roots form. Fertilize with a mild fertilizer solution when all clones have started vegetative growth.

Any sign of slime, pests, or disease means there are problems, and clones should be removed from the garden. Transplant only the strongest, well-rooted clones. Slow-rooting clones should be kept in the cloning chamber or culled out. Do not move clones below bright light until they have fully developed rot systems. Once transplanted, clones are ready to harden-off.