Cloning ?

Chapter Thirty-Two - Cloning

Clones are a fancy name for cuttings. Almost everyone has taken a piece of a plant and placed it in water until it grew roots. As it developed, the leaves, flowers, fruit and other characteristics of the plant were exactly the same as the donor plant from which it was taken. That cutting was an exact genetic reproduction of a donor plant. Many growers prefer to start their garden from clones. There are several reasons for this. Growers must start only a few more plants than needed because all the clones, being the same genetic make-up, are the same sex as the donor, presumably, female. Clone gardens are usually derived from donors which were ex- ceptional plants. The new plants are every bit as exceptional as the donor. The plants have the same growth and flowering patterns, maturation time, nutrient requirements, taste and high. The garden has a uniformity that allows the grower to use the space most effi- ciently. Unique plants with rare genetic characteristics can be saved genetically intact. For example, a grower had an infertile female. Even though the plant was in the midst of a mixed field, it produced no seed. At the end of the season the plant was harvested and that rare quality died with the plant. Had the grower made cuttings, that plant's traits would have been preserved. Clone gardens have disadvantages, too. If a disease attacks a garden, all of the plants have the same susceptibility because they all have the same qualities of resistance. The home gardener may get tired of smoking the same stuff all of the time. In terms of genetics, the garden is stagnant; there is no sexual reproduction tak- ing place. Cuttings root easiest when they are made while the plant is still in its vegetative growth stage. However, they can be taken even as the plant is being harvested. Some growers think that cuttings from the bottom of the plant, which gets less light, are better clone material, but cuttings from all parts of the plant can root. Cuttings are likely to have a high dropoff rate if they are not given a moist, warm environment. They often succumb to stem rot or dehydration. Stem rot is usually caused by a lack of oxygen. Dehydration results from improper irrigation techniques, letting the medium dry, or from overtaxing the new plants. Cuttings do not have the root system required to transpire large amounts of water needed under bright light conditions. Instead, they are placed in a moderately lit area where their resources are not stressed to the limit. Growers who are making only 1 or 2 cuttings usually take the new growth at the ends of the branches. These starts are 4-6 inches long. All of the large leaves are removed and vegetative growth is removed except for an inch of leaves and shoots at the end-tip. If large numbers of cuttings are being taken, a system using less donor-plant material is preferred.

Starts can be made from many of the internodes along the branch which have vegetative growth. These starts are at least an inch long and each one has some leaf material. If the cuttings are not started immediately, air may get trapped at the cut end, preventing the cutting from obtaining water. To pre- vent this, 1/6 inch is sliced off the end of the stem immediately before planting or setting to root. All cuts should be made with a sterile knife, scissors, or razor blade. Utensils can be sterilized using bleach, fire, or alcohol. Some horticulturists claim that scissors squeeze and injure remaining tissue, but this does not seem to affect survival rates. It usually takes between 10 and 20 days for cuttings to root. They root fastest and with least dropoff when the medium is kept at about 65 degrees. Small cuttings can be rooted in water by floating them. The ""Klone Kit", which is no longer available, used small styrofoam chips, which are sold as packing material, to hold the cuttings. Holes were placed in the chips with a pencil or other sharp instru- ment, and then the stem slipped through. The unit easily floats in the water. The kit also included rooting solution, 100 milliliter plastic cups (3 ounce), and coarse vermiculite. The cups were half filled with vermiculite and then the water-rooting solution was poured to the top of the cups. As the water level lowered, the cut-tings rooted in the vermiculite. Styrofoam chips can be floated in the water without solid medium. When the cuttings begin to root, they are moved to ver- miculite. One grower adapted this technique using one-holed cork stoppers instead of styrofoam chips. He used 1 x 2 inch, 72-unit seed trays and placed one cork in each unit. The water is changed daily, or a small air pump can be used to supply air to the water, so that the submerged plant parts have ac- cess to oxygenated water. A water-soluble rooting agent containing B1 and the rooting hormone indolebutyric acid promote root growth. A very dilute nutrient solution which is relatively high in P is added to the water once roots appear. When the cutting develops roots, it can be planted in a moist medium such as vermiculite and watered with a dilute nutrient solution for 10-15 days. One popular commercial cloning kit consists of a tray which holds peat pellets in a miniature greenhouse. The cuttings are plac- ed one to a peat pellet. Fairly small-to-large-size cuttings can be placed in these pellets. Cuttings can be rooted in the same way as any other woody cutting. First, the branch is cut into two, including some foliage on the upper segment of the branch. Smaller cuttings can be made, but they are harder to manipulate. Then a diagonal cut is made at the bottom end of the shoot. The cutting is put into a unit of 1 x 2", 72-cup seed trays, 2" pot or 6 ounce styrofoam cup filled with fine vermiculite wetted to saturation with water containing a rooting solution such as Klone Concentrate. To place the cutting in the medium without scraping off the fungicide, a thin pencil or other rod is pushed into the medium, creating a hole. The cutting is gently placed in the hole and the medium gently pressed down tightly around the stem so that there is moist contact. Cuttings do best and have a much higher survival rate when they are rooted in a humid atmosphere. The tray or containers are covered with a clear plastic cover which keeps moisture high and allows the light in. The cuttings are kept warm and within a few weeks they develop into rootlings. One grower used a pyrex dish and cover to root her cuttings which were placed in 1½ inch square containers.

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Got any tips for hard to clone plants?

Some varieties are easier to clone than others. There are Sativas that will sprout roots so easy, you can (almost) stick them in the ground and forget em. But then there are some early Indicas that you can baby and they will just sit there and starve to death. So there are a few things you have got to look at. Help the roots grow. Figure out where the roots will grow on your cutting before you actually cut it. Keep this portion of the stem dark for a week or two by wrapping some tape around it. This is called "etiolation" and will encourage rooting. Make the cutting with a sharp anvil pruner or very sharp scissors, and sterilize them after each cut. A dull pruner will crush the stem and it will be harder for the roots to form. A razor blade will make an even cleaner cut, which will also help rooting, but don't blame me if you cut yourself. Try to make the cut at angle to increase the surface area it has to absorb water. The plant needs air to help the roots form, but don't let any get in the stem. This will cut off the capillary action and make the poor cutting work harder. Immediately dunk the cut end in water or rooting solution to prevent this from happening. You could even take it over to the sink and make a second cut under running water if you're really worried about it. Leave it in the rooting solution for a day or so. If you just leave it in the water, you might get lucky and sprout some roots, but they really need some oxygen. You can actively provide O2 by aeration or passively aerate by using an airy medium. Another thing that makes the cutting work harder is breathing itself. Use a plastic dome or humidity tent to limit transpiration and keep the medium from drying out, and. Half of a 16 oz plastic drink bottle fits right on top of a 3 inch clay pot. Another way to limit transpiration is to cut about half off of each leaflet. You will still have the same number of leaves on the stem, but the surface area has decreased. This also helps control fungus by preventing the leaves from contacting the dome or the medium. The proper lighting is also important. Direct sunlight will heat the air in the dome too much, but they're not going to root in the dark either. Fluorescents are ideal for this. An HID is OK if it’s not too close, or you could even give them a bit of indirect sun from a window if you can keep them warm. You’ve kept an eye on the pH and the nutes, and you see it’s starting to grow again, so its safe to assume that it has roots and you can remove the humidity dome. Occasionally a cutting may wilt a little at first, but give it a mist and it should perk up. If none of these tips help, either consider tissue culture or finding a different mother.

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