Hemp has long been known as a cannabis variety with psychoactive properties, but it also has incredible nutritional value. It is a great crop for sustainable farmers to add to their annual rotation because it doesn’t require nitrogen fertilizer, and its deep roots help regenerate the soil, making it ideal for growing a wide variety of crops. Its quick growth cycle of just four months also makes it easy for producers to manage and grow.
The hemp plant is an erect annual herb with slender cane-like stalks and fragrant flowers in greenish yellow or dark brown clusters. The seeds grow in elongated spikelike clusters on pistillate, or female, plants and pollen-producing flowers form in branched clusters on staminate, or male, plants. Both the seed and oil have been used as a food and nutrition source for thousands of years. Hemp seeds are high in omega-3 fatty acids, which may help lower blood pressure. Hemp oil contains the essential fatty acid gamma-linolenic acid (GLA), which is thought to help reduce inflammation and other chronic conditions, such as rheumatoid arthritis.
Its high protein content also makes it a valuable food for vegetarians, vegans and flexitarians. Hemp seeds contain the amino acid l-arginine, which when broken down in the body produces nitric oxide, a molecule that makes the blood vessels relax and dilate. This helps to lower the heart rate and blood pressure, which may reduce the risk of coronary artery disease.
The fibres of the hemp plant are used for a variety of products, including ropes, paper, canvas and sailcloth. The cultivation of the plant was one of the most important industries in pre-industrial Europe, but production sharply declined as synthetic fibres were introduced. In some parts of the world, hemp is still cultivated for its fibres, such as in China, where it was first cultivated in 2800 bc.
Hemp is a versatile crop, producing both fibre and grain. It can be grown at a range of heights, from 1 to 1.9 meters, although shorter varieties have a greater grain yield. Hemp is intolerant to poor soil drainage, salinity and excessively wet growing conditions. It is best suited to light to moderately fertile soils, with a pH between 6.0 and 7.5.
The hemp crop is a dioecious species, requiring cross-pollination to produce seed. It is usually a double-purpose crop, where the taller varieties are primarily bred for fibre and the short ones for grain. The crop can be harvested from early August to late September, depending on the desired end use. When harvesting, care should be taken to avoid shattering or bird damage, and to ensure a good grain crop by not allowing the stems to wrap and block combine machinery. Hemp requires rapid drying to prevent mould and mildew, so harvesting should be completed as soon as possible after the plant dries out. Hemp is a high-yielding, low-input crop and has a high return on investment. It is also a good economic alternative to more labour-intensive crops, such as tobacco and cotton, which require heavy inputs of chemicals.
