Hemp seeds can be sown using available grain sowing machines. It is necessary to use certified seed that is obtained from a certified seed supplier.
The sowing norm depends on what the hemp is cultivated for. The sowing norm for seed hemp is approximately two times lower than for fibre hemp, being about 30 and 65 kg/ha, respectively (the exact recommended figure depends on the specific variety (Desanlis, F., 2005)). This is due to the fact that if seeds are sown more sparsely, the plant branches out more and is shorter, grows more flowers and thus has a bigger seed yield. Densely sown plants do not branch, the stem is uniformly thin and long, and the fibre is of higher quality.
Plant growth depending on the sowing density
Seeds should be sown 2 to 5 cm deep in soil. Gentle rolling is advisable to avoid erosion caused by spring rains (Callaway, J., C. 2004) and increase contact between the seeds and the soil (Barron, A., et al. 2003).
The optimal soil temperature is around 10°C, the minimum soil temperature suitable for sowing is considered to be 6°C (Barron, A., et al. 2003). The seeds start germinating within 24 to 48 hours, the first leaves should emerge 5 to 7 days after sowing. If sowing is done earlier, plant growth may be stunted and the yield may decrease (Messenger & Low, 1996 cit. Barron et al. 2003).