Marijuana Botany by Robert Connell Clarke Grafting Intergeneric grafts between Cannabis and Humulus (hops) have fascinated researchers and cultivators for decades. Warmke and Davidson (1943) claimed that Humulus tops grafted…

Marijuana Botany by Robert Connell Clarke Making an Air Layer A recently sexed young limb 3-10 mm (1/8 to 3/8 inch) in diameter is selected. The site of the layer…

Marijuana Botany by Robert Connell Clarke Soil Layering Soil layering may be performed in several ways. The most common is known as tip layering. A long, supple vegetative lower limb…

Marijuana Botany by Robert Connell Clarke Techniques of Layering Almost all layering techniques rely on the principle of etiolation. Both soil layering and air layering involve depriving the rooting portion…

Marijuana Botany by Robert Connell Clarke Layering Layering is a process in which roots develop on a stem while it remains attached to, and nutritionally supported by the parent plant.…

Marijuana Botany by Robert Connell Clarke Soil Treatment Solid media provide anchors for cuttings, plenty of darkness to promote etiolation and root growth, and sufficient air circulation to the young…

Marijuana Botany by Robert Connell Clarke Rooting Media Water is a common medium for rooting. It is inexpensive, disperses nutrients evenly, and allows direct observation of root development. However, several…

Marijuana Botany by Robert Connell Clarke Oxygen and Rooting The initiation and growth of roots depends upon atmospheric oxygen. If oxygen levels are low, shoots may fail to produce roots…

Marijuana Botany by Robert Connell Clarke Hardening Off The cuttings usually develop a good root system and will be ready to transplant in three to six weeks. At this time…

Marijuana Botany by Robert Connell Clarke Making Cuttings Cuttings of relatively young vegetative limbs 10 to 45 centimeters (4 to 18 inches) are made with a sharp knife or razor…

Marijuana Botany by Robert Connell Clarke Rooting A knowledge of the internal structure of the stem is helpful in understanding the origin of adventitious roots. The development of adventitious roots…

Marijuana Botany by Robert Connell Clarke Asexual Propagation Asexual propagation (cloning) allows the preservation of genotype because only normal cell division (mitosis) occurs during growth and regeneration. The vegetative (non-reproductive)…

Marijuana Botany by Robert Connell Clarke Seed Selection Nearly every cultivated Cannabis plant, no matter what its future, began as a germinating seed; and nearly all Cannabis cultivators, no matter…

Marijuana Botany by Robert Connell Clarke Pollination Techniques Controlled hand pollination consists of two basic steps: collecting pollen from the anthers of the staminate parent and applying pollen to the…

Marijuana Botany by Robert Connell Clarke Data Collection Keeping accurate notes and records is a key to successful plant-breeding. Crosses among ten pure strains (ten staminate and ten pistillate parents)…