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Determination of the yield of an illegal indoor cannabis plantation (YILCAN)

Research project DR/56 (Research action DR)

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Description :

In recent years, the Belgian police observed a considerable rise in the number of both small-scale and large indoor cannabis plantations. The juridical answer to this phenomenon needs to be consistent in the sphere of both confiscation and seizure of the gains perpetrators obtained from illegal cannabis plantations. Nowadays, judicial authorities base this answer on the physical yield and resulting financial gains estimated in a Dutch study from 2005. The latter study nevertheless has significant shortcomings, strongly suggesting that current yields are underestimated. The YILCAN project addresses this problem by investigating the influence of a number of yield determining factors in a controlled cannabis growing experiment in which illegal indoor conditions are imitated in the greatest detail.

At the onset of the project, as much information as possible on indoor cannabis cultivation in Belgium will be collected from grey literature sources (predominantly from the internet). Additional information will be retrieved from the Belgian Federal Police. This information will be used in the experimental design so as to adequately imitate a typical illegal indoor cultivation setting.

Factors that are investigated include:

- four cannabis varieties: of which literature claims differing, but nevertheless high yields and of which judicial authorities know they are frequently found in illegal indoor plantations;
- two plant densities: 16 and 20 plants per m²;
- two different substrates: potting soil and hydroponics
- two light intensities: 600 W/m² and 400 W/m².

Other growth factors (pruning, fertilizing, irrigation, temperature, ventilation, etc.) are standardized. Cultivation starts from seeds that are bought in Dutch growshops. In a first stage, parent plants will be grown from which cuttings will taken until a total of 576 cuttings are obtained. The latter cuttings will subsequently be grown according to a standardized regime and to which the aforementioned factors will be applied. After each growth cycle, plants are harvested, cut and dried, according to procedures advocated by ‘grey’ literature resources. Next, the dry weight of cannabis buds is determined per plant. During one year, different growth cycles will be performed and the differences between the different growth factors in yield per plant and per m² will be evaluated. Furthermore, the influence of each of these factors on the number of possible harvests per year will be determined.

Results of this investigation of agricultural yield will be used in a criminological research component in which the monetary value (per m²/plant per harvest and per year) of the cannabis buds will be determined, using street value data. Mechanisms of price setting, as well as financial gains of cannabis growers will be determined in relation to different cannabis markets. Earlier research revealed that Belgian cannabis is frequently marketed through Dutch coffeeshops. Besides these (tolerated) coffeeshops, a great number of illegal outlets prevail: e.g. street dealers and drug joints. Cannabis retail, however, is outside of the project’s research focus. First, relevant police and justiciary files will be thoroughly analysed. In addition, key persons active in cannabis cultivation and trade will be questioned. The latter will be reached applying the so-called snowball sampling procedure, which consists of asking respondents to identify other potential respondents and to introduce the researcher to them.

The monetary values thus obtained, in combination with the earlier determined agricultural yield data, will bring forth a model for determination of the gains obtained from illegal indoor cannabis cultivation in Belgium.

Documentation :

Opbrengstbepaling van een illegale indoor cannabisplantage (YILCAN) : samenvatting    Brussel: Federaal Wetenschapsbeleid, 2011 (SP2340)
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Rendement d'une plantation de cannabis (YILCAN) : résumé    Bruxelles : Politique scientifique fédérale, 2011 (SP2341)
[To download

Determination of the yield of an illegal indoor cannabis plantation (YILCAN) : summary    Brussels : Federal Science Policy, 2011 (SP2342)
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YILCAN : eindrapport    Brussel : Federaal Wetenschapsbeleid, 2011 (SP2371)
[To download

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