Crop development and flowering of short day plants is hastened by short-days and delayed by long days. When planted in autumn hemp will tend to flower and set seed without producing the long stem lengths required for fibre production. There are varietal differences and the SA research program will be evaluating varieties that are less photo-period sensitive and better adapted to winter sowing. The plant is best suited to well structured neutral to alkaline clay and loam soils with good water holding capacity which are not subject to waterlogging. Although susceptible to early weed competition, the tall growth habit and high plant density enables hemp to compete well with weeds.
European experience suggests hemp is less prone to pests and diseases than many other crops.
Yields under SA dryland conditions have yet to be established. Harvesting Harvesting for paper pulp and textiles occurs at the end of flowering of the female plants and before seed formation. The process is similar to making hay. The crop is cut with a mower or windrower, left to ret or dry in the paddock for several days if it is to be used for paper products and several weeks where it is destined for textile usage. During 1995 three research trials representing a range of climatic and soil conditions will be conducted.