Cloning in horticulture means vegetative (asexual) propagation: a piece of the plant, usually a shoot tip, is cut off and encouraged to grow roots. The rooted cutting is a genetic copy of the donor, including its sex, so every clone of a female is female.
In practice
A typical cannabis cut is 8-15 cm (3-6 in) with 2-3 nodes, taken from a healthy vegetative plant, trimmed of lower leaves, dipped in a rooting hormone and set in a plug of rockwool, peat, coco or an aeroponic cloner. Roots usually appear in 7-14 days at about 22-26 °C (72-79 °F) medium temperature, high humidity and gentle light (about 100-200 µmol/m²/s).
Cloning is how growers keep a selected keeper, run uniform sea-of-green crops and preserve cultivars. Genotype carries over; pathogens such as viroids carry over too.
Don't confuse with
- Cutting: the piece of plant itself; cloning is the whole process.
- Tissue culture: cloning from tiny explants in sterile culture; can clean up pathogens.
- Reproductive cloning (animals): unrelated technology.
Myth check
House position: clones do not drift genetically. Apparent decline is pathogens or care. Cuts from different parts of a plant can behave differently (topophysis), so take them from consistent locations.
The zone of dividing cells at the very tip of a shoot (or root) that produces new leaves, nodes and stem; removing it is what topping does.Rooting hormone is an auxin preparation, usually indole-3-butyric acid (IBA), applied to a cutting's base to speed and increase root formation.Coco coir is a growing medium made from processed coconut husk, prized for holding water and air at once; it binds calcium and magnesium unless buffered.Aeroponics grows plants with roots hanging in air inside a dark chamber, wetted by sprayed nutrient solution; low-pressure (LPA) systems use ordinary pumps and spray heads.Photosynthetic photon flux density: the number of PAR photons landing on one square metre each second, in µmol/m²/s; the standard measure of light intensity at the canopy.SOG (sea of green) grows many small plants at high density with little or no veg time, each making one main cola, to shorten the cycle.The genotype is the set of alleles a plant actually carries, either at one locus or across its whole genome, as opposed to the traits you can see.Tissue culture is growing small pieces of a plant on sterile nutrient gel in a sealed vessel, used to multiply, clean up and store cannabis genotypes.A cutting is a piece of shoot, usually a tip with two or three nodes, removed from a plant so it can be rooted into a new, genetically identical plant.A mother plant is a female kept permanently in vegetative growth to supply cuttings, so a selected genotype can be propagated as clones indefinitely.A cloning dome is a clear lid over a tray that keeps humidity high around unrooted cuttings or seedlings, reducing water loss until roots form.
