Yield and turnover of illicit indoor cannabis (Cannabis spp.) plantations in Belgium

In prosecution, Belgian judiciary currently uses outdated yield figures (28.1 g per plant, sold at € 3/g at grower level) for fining illicit indoor cannabis plantations. Using state-of-the-art cultivation techniques, our growth experiments showed that yield is better expressed in g/m2 cultivated surface area rather than in g per plant, and that yield varies significantly between different cannabis strains. It was found that the lower-bound of the one-sided 95% confidence interval of the yield of an indoor cannabis plantation can be set at 575 g/m2. Prices and pricing mechanisms were investigated using interviews with respondents selected through snowball sampling. Results reveal that (i) the Belgian cannabis market chain is highly complex; (ii) unit prices are predominantly determined by transaction sizes; but also (iii) a set of product- and socially-related price-fixing mechanisms have an equally important role. At grower level, respondents reported prices for 1 g of dry cannabis buds to range € 3.00-4.25.