What is Cannabis?
Pot Night - The Book, Channel 4 Television, 1995
Dr Tim Holden
Cannabis sativa is a tall, erect, annual herb which grows to a height of 1-5m (3.3-16.4 ft) and is closely related to the hop and the stinging nettle. Cannabis plants are wind-pollinated, with male and female flowers usually developing on seperate plants. Male flowers are yellow, up to 5mm (1/5 in) long and a have no petals. The female flowers are surrounded by a leafy covering with thick, glandular hairs; similar hairs are present on the leaves and stem, and it is in these that the narcotic-containing resin is mostly concentrated. Although the uppermost leaves commonly have only one leaflet, the remainder are distinctively palm-like, with 3-11 toothed leaflets per leaf. The form of the plant is largely dependent upon the variety, with those grown for fibre (i.e.hemp) being less branched than those grown for other purposes.
The seed will germinate at temperatures above 1 degree C (34F), but during the growing season, it requires temperatures of 15-25 degrees C (60-80F) and adequate rainfall. Hotter, more tropical climates promote the production of the narcotic resin, although, again, this is very dependent upon the varieties sown.
History C.sativa appears to have originated somewhere in Central Asia and was probably first brought into cultivation for its fibre. It has been grown in China for at least 4500 years, possibly as far back as the Neolithic period. It is thought to have reached Europe by 1500 BC, and by AD500, it had become a significant fibre crop there. The narcotic properties were known in India by 100BC but this aspect of the plant was not recorded in Europe until much later. The drug was not introduced to Western medicine before about 1840.
Cultivation For fibre production, the seed is sown thickly, with harvesting occurring some four or five months after sowing. The male plants produce the best fibre and are often harvested first, with the female plants being allowed to stand in order for the first seeds to be collected.
For the production of the drug, the plants are sown mre thinly. In India, they are planted in rows and thinned when 20cm (8 in) high. The male plants are pulled out as soon as they can be recognised, and the unfertilized female plants are allowed to continue growing until they are about five months old.
Uses The Plants are cultivated for three main purposes: fibre from the stems; oil from the seeds; and a narcotic substance from the leaves and flowers. The varieties used for fibre are known as hemp and are particularly valued for their long, durable fibres. Their main use is in the manufacture of items such as canvass, twine, and rope.
The seeds yield up to 35 per cent oil, which is used in paints and varnishes, in the manufacture of soaps and for bird and poultry feed.
Three different classes of narcotic are produced: bhang (the dried leaves and flowering shoots of male and female plants); ganja (the dried and compressed, unfertilised female flowers); and charas (the crude resin collected from the tops of the plants by rubbing or beating).