Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

bacteria, fungi, viruses, and other diseases already present. Use sharp scissors, razor, or razor blade dipped in alcohol, vinegar, or bleach (five to ten percent solution). Wash your hands thoroughly beforehand.
    Make sure to have all cloning supplies within arm’s reach–rooting cubes, hormone, razor or scissors, humidity dome, etc.–before you start to take clones.

Cloning: Step-by-Step
    Step One: 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, leach 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 help wash out nitrogen. Do not add fertilizer.
    Step Two: With a sharp blade, make a 45-degree cut across firm, healthy 0.125-0.25-inch-wide (3-6 mm) branches, two to four inches (3-5 cm) 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 clones in water while making more clones.

Make a 45-degree cut across the stem to cut the clone.

Trim off one or two sets of leaves.

Hold cut clones in a glass of water until you are ready to dip in hormone and plant.

Dip trimmed stem into the rooting gel or liquid hormone. Make sure stem is covered with the proper amount of rooting hormone.

Place the stem covered with rooting hormone into the root cube.

Pinch the top of the root cube so that growing medium is in full contact with the stem.
    Step Three: Rockwool and Oasis™ root cubes are convenient and easy to 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, chop stick, nail, etc., to make a hole in the rooting medium–a little larger than the stem. The hole should stop about one-half inch (1.5 cm) from the bottom of the container toallow for root growth.
    Place a tray containing rooting cubes or plugs into a standard nursery rooting flat. 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.

Grow clones until they are well-rooted. Always remember to label clones when planting.
    Step Four: Use a rooting hormone, and mix (if necessary) just before using. For liquids, use the dilution ratio 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 Five: Lightly water until the surface is evenly moist. Keep cuttings moist at all times. Clones have no roots to bring water to leaves. 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 Six: Clones root fastest 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 (18 cm) above clones or a 400-watt metal halide 4-6 feet (1.2-1.8) away supplies the perfect amount of light for clones to root. Cool white fluorescents (or a combination of warm and cool white) are excellent for rooting.

Humidity domes fit over flats of clones to retain humidity. The domes on the right are covered with lightweight Agronet to lower light on new clones.

Above: Best humidity ranges for cloning.

Right: Best temperature range for growing medium.

A fogger in the cloning room will ensure humidity stays above 95 percent

To lower transpiration, cut clone leaves in half before sticking.

An incandescent light bulb attached to a rheostat provides exacting control of bottom