The science bit
Coarse, scabrous, bushy herb up to 4m tall. Leaves grey-green, up to 12cm long, palmate with 3-9 lanceolate leaflets, margin serrated. Individual plants either have male or female flowers (dioecious). Flowers small, green and clustered. Fruits small, dry and thin-walled (achene), contain only one seed. Pollinated by wind.
- Hemp grows fast, is very adaptable to soil and climatic conditions and is undemanding on resources such as artificial fertilisers and pesticides. It provides a good break crop for the farmer, giving the land a rest from other crops and helping to prevent disease.
- It is a potential flagship sustainable crop for the 21st century, but there's a reason why our fields aren’t full of it. It produces a substance that became socially controversial in the early part of the 20th century: tetrahydrocannabinol (THC), which as well as having many medicinal attributes has been used as a recreational drug. In recent years breeding and selection has resulted in cultivars low in THC, and hemp is once again being considered by governments as a useful crop.
- One of the oldest relics of human industry is a bit of hemp fabric dating back to approximately 8,000 BC.
- Hemp is six times as strong as cotton, much more resistant to weathering and wear, and more lustrous and absorbent. It is also much more environmentally friendly to grow.
- Hemp growing became commonplace in Britain under the Romans and continued into the mid-1940s. In the 16th century Henry VIII made hemp cultivation obligatory.
Where it grows
Originally from the Indian subcontinent, it spread from China to France and from Russia to Africa. It requires full light but can grow in most soil types providing they are damp.
For centuries hemp has provided raw materials for communication, textiles, sea transportation, medicine, oil and much more. It is one of the most useful multi-purpose crops of the temperate world quoted as having over 25,000 end products. For example, the seed can be used as a food protein and the outer stem provides fibre for ropes and canvas for tents. It is illegal in most countries because the leaves can be dried and smoked to provide a mild narcotic.
The fibre crop in Europe is today mostly grown to supply the specialist paper industry, or for the nonwoven converting industry supplying automotive companies.
In England low-THC hemp is grown for fibre under Home Office drug licence and supervision. In Scotland, a high-THC crop is grown under secure glasshouse conditions and under the same drug licence, and being used in the development of a pharmacological muscle relaxant for multiple sclerosis sufferers.
In order to grow hemp at Eden we needed an industrial licence and a physical barrier, so the barrier became the artistic installation: the Hemp Fence designed by George Fairhurst. It is also a symbolic barrier: visitors are invited to stick their neck out to see what is on the other side.
- Lanceolate: narrowly ovate and tapering to a point.
- Palmate: when all lobes originate from a central point (lobes are incomplete divisions in the leaves).
- Scabrous: rough to the touch.