Nearly everyone has taken a cutting from a house plant and placed it in water. Within a short time roots grew and the new plant was ready to be placed in a container with medium. The new plant had the same genetic make-up of its clone mother. The new plant’s growth, flowers, and reactions to environment were exactly the same as the plant from which it was taken.
The genetic make-up, and therefore the characteristics of a plant started from seed cannot be determined until the plant is grown. Although the lineage of the plant may provide a fair amount of information, there is no way of pre-determining its exact qualities. There are literally billions of possible combinations of genes that the two parents can supply. No two plants from seed are likely to be identical.
There are many advantages to growing genetically identical plants. Here are some which growers have brought to my attention.
- The plants have uniform growth characteristics so the garden is easier to maintain. Each plant grows to the same size, has approximately the same yield and matures at the same time as its sisters. Starting from seeds, plants of the same variety exhibit subtle differences in growth patterns.
- Buds from clone sisters will be of the same potency and taste the same.
- There will be no males in the garden. Since all clones from a single "clone mother" have the same genetic make-up, clones from a female plant can be only female. Usually about half of the plants from seeds turn out to be male. Using clones saves valuable garden space which would have been used to grow males.
- Clones seem to exhibit shorter internode length (distance between the leaves) which means that the garden has shorter, stouter plants.
- The exact genetic make-up of a particular plant is easily preserved. This means that the characteristics of a super-plant or other novel specimen can be continued.
There are also disadvantages to growing clones:
- All of the plants from a single clone mother yield the same product. There is no variation. Gardeners growing for personal consumption often wish to grow several different varieties.
- There is no genetic progression. Since no breeding is taking place, the genetic line remains static. There are no surprises and no new finds. Using clones, there is no way of genetically adapting a line to a particular environment.
HOW CLONES ARE MADE
Cuttings are taken from soft green tissue because the drier, woody sections of the plant do not root as easily. Sections taken are 2-5 inches long with several sets of leaves. The cut is made with a very sharp blade which makes a clean, straight cut, rather than a scissor which pinches and injures the tissue. As the cuttings are made they are placed in a bowl filled with lukewarm water to prevent them from drying out.
Once all the cuttings are taken, they are trimmed of their lower leaves, leaving only one or two sets plus the growing tip. This helps to prevent the cutting from being water stressed. If the leaves were left on the cutting, they would create water demands that the stem end, with a limited draw, cannot meet. Any large fan leaves are also removed for the same reason.
Next, the rooting solution is prepared. Liquid type rooting compounds are the best to use because the active ingredients are in solution and are guaranteed to come in contact with the stem. Powders are often scraped off as the cutting is set in place, and drop off when placed in water. Some popular rooting solutions which work well are Olivia’stm, Klone Concentratetm, Hormextm and Wood’stm. The solution is used as directed for woody plants.
The trimmed cuttings are placed either in water or a rooting medium such as vermiculite, rockwool or floral foam which has been watered with one quarter strength flowering formula fertilizer solution. At least ¾ inch of stem is inserted in the rooting medium which is patted down to make sure that the stem is in direct contact with it.
The cuttings growers make are placed in an area of high humidity to limit water stress. Growers often construct a "mini-greenhouse" using plastic wrap placed over the rooting chamber. Some trays come with clear
plastic covers to retain moisture. The cover is removed when the plants develop roots. A fine mist spray helps relieve water stress. The clones respond best to a moderate rather than a bright light. Some gardeners light the clone garden using 2 tubes for an area 4 x 2 feet, 10 watts per square foot. Clones being rooted in water do best when the water is changed frequently and aerated using a small pump and an aquarium bubbler. Rooting blocks or medium must be kept well saturated.
The temperature of the medium affects the rooting time of the clones. Cuttings root fastest when the temperature is kept in the low to mid 70’s. At lower temperatures the cuttings take longer to root and are more likely to suffer from infections. Growers report the easiest way to keep the cuttings warm is to use a heating cable or heating mat made especially for germinating and rooting plants. These are available at most plant nurseries and are very inexpensive.
Given good conditions, cuttings usually root in one to two weeks. Some varieties are easier to root than others. For instance Big Bud, is notoriously difficult to root. Skunk and Northern lights are much easier to clone.
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