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Homegrown's place in the UK cannabis market

Whilst the plethora of "Grow your own" guides, the ready availability of a wide range cannabis seeds and growing equipment through the Internet and other outlets and the publishing success of regular magazines for the cannabis user would suggest widespread interest in home cultivation, information on its extent is scarce. The little information we do have comes from the regular surveys of cannabis users carried out by the Independent Drug Monitoring Unit (IDMU). Since 1984, the IDMU has been distributing questionnaires to regular cannabis users at popular music festivals and have provided a valuable picture of drug consumption patterns, prices and markets in the UK. Although lacking the finer points of sample representativeness, these regular surveys are generally viewed as a reliable barometer of changes in the UK drug market.

The findings from their most recently published survey for 2001 found that domestically-produced cannabis was now taking a dominating role in the UK cannabis market and made up nearly half of UK cannabis consumption. Homegrown had now overtaken Moroccan (soap-bar) resin, hitherto the major product in the cannabis market, for the first time. With the 1984 survey reporting just 10% of the respondents using homegrown, the growth in the availability of UK-grown cannabis is apparent.

Cannabis cultivation systems in the UK vary from one light in a cupboard, up to industrial units holding thousands of plants. The vast majority of growers now use high intensity lighting, and hydroponic nutrients and cultivation vessels tend to be the norm (although higher potencies are generally found from organic-grown plants), although methods vary, most growers will have separate areas for growth and flowering, allowing simultaneous propagation of cuttings from mother plants, and growing these to the desired height (with 18-24 hours light) before transferring to the flowering zone (12 hour light/dark cycle). Outdoor cultivation is becoming much rarer, as the plant is now more easily recognised by members of the public.

Growers may cultivate a few large plants, or many small plants, with the yield from individual plants ranging from under one gram to 100 grams or more. The number of plants is therefore an unreliable guide to the potential yield or scale of cultivation in a particular system. Smaller plants may be harvested more quickly although, broadly speaking, the potential yield of a system is a function of the available space, the intensity of the lighting, and the variety grown (short bushy plants obviously yield more than tall spindly plants).

Growers with a single cultivation chamber cannot sustain continuous production, and would take 4-6 months to harvest a crop. With efficient use of two growing zones, it is possible to reduce the interval between successive harvests to 2-3 months.

A two-chamber system with 2-3 lights, and a flowering area of 1-2m2 can sustain personal consumption for a moderate to heavy user-users who grow cannabis tend to smoke more than those who have to buy it. However, users who grow cannabis are also roughly twice as likely to be arrested for cannabis offences than those who have never grown cannabis plants.

The majority of cannabis growers grow the plant in indoor cultivation systems. Casual growers will often plant a few seeds found in imported bush and grow a few plants on windowsills or balconies, although an increasing number of respondents are growing cannabis from a combination of pedigree seeds and cuttings, using hydroponic systems and high-intensity horticultural lighting.

Between 1994 and 2000, the proportion of growers using hydroponic cultivation systems trebled from 6% to 19%, and use of high power lighting increased from 17% to 41% while natural light usage fell from 77% to 56%. Over the same period the proportion of growers using seeds from deals of imported cannabis bush fell from 49% to 21% (probably reflecting reduced market availability), while the proportion using pedigree seeds rose from 35% to 57%.

In 2000, growers tended to use more lights, with an average of 4.5 lights with an average total wattage of 1067W, compared to just under 2 lights with total wattage of 421W in 1999.

This increasing high-tech trend was also reflected in the quantity grown, in 1998 growers produced an average of 12 plants with an total yield of 189g, in 2000 the figure was 23 plants with average yield of 462g.

Growers tend to be heavier users, with the average non-grower smoking 2.6 reefers or pipes a day and using 21g per month, compared to growers having 6.3 smokes per day and using 30g per month.

Home Office Seizures: Arrests for cannabis cultivation peaked in the mid 1990s, when many police forces were actively targeting growing operations. Since 1995 the number of seizures has fallen substantially, suggesting domestic cannabis cultivation to have fallen down the list of police priorities, although recent seizures have involved larger numbers of plants, with a higher proportion involving commercial-scale operations.













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