Hemp (Cannabis sativa L.) is used to make food, health products, fabric, rope and natural remedies. It has a high concentration of soluble and insoluble fiber and is a good source of omega-3 and omega-6 fatty acids.
The 2018 Farm Bill made hemp and products derived from it legal in the United States. Hemp contains less than 0.3 percent THC, which makes it different from marijuana and other cannabis.
Plant
The hemp plant is a tall, annual herb. Its slender canelike stalks produce leaves and flowers, which produce either seeds or fibers. The seed-producing flowers grow in elongate spikelike clusters on pistillate, or female, plants and pollen-producing flowers grow in many-branched clusters on staminate, or male, plants. Hemp seeds are rich in important vitamins, minerals and proteins as well as unsaturated fatty acids. They can be used as a spread or added to muesli or a salad.
The ideal growing environment for hemp is in loose, well-aerated, loamy soil with adequate fertility and high levels of organic matter. Hemp can also be grown on land that has been contaminated, using it to improve soil quality and promote phytoremediation (the natural decomposition of pollutants).
Hemp requires a significant amount of moisture to reach maximum yields, particularly during the flowering and grain set period. Dryness during this stage reduces seed yields and leads to poor-quality fibers. The crop can be harvested for fiber, or for grain. Harvesting for fiber production can be done with standard farm equipment, though a special cutter-binder or straight sickle mower is recommended. For harvesting for grain, a grain combine or swather should be used with caution because long stems may wrap and cause machinery damage.
Hemp has been cultivated for millennia as a source of fibre, oil, food and medicine. It has been an important component of the world's earliest cloth, rope and paper. Its strong, durable fibers make it a desirable material for cordage—twine, yarn, cable and string—and coarse fabrics like sacking and canvas. Its lustrous, cellulose-rich fibre is also used to make textiles. Its seeds are nutritious and used to make a variety of foods and dietary supplements, as well as fuel.
Seeds
Hemp seeds are a protein-rich snack, with a nutritional profile that includes antioxidants, healthful fats, and minerals. They are also a good source of calcium, iron, magnesium, and potassium. The shells are a rich source of fiber, and grinding them helps the body absorb the nutrients. Hemp seeds can be eaten whole or toasted, and they are often mixed with other ingredients like nuts, grains, or dried fruits to make hemp-seed milk.
Hemp is an annual crop that grows best in temperate zones. It thrives in sandy loam with a moderate amount of water. Plants cultivated for fibre grow very tall with long branches, while plants grown for seeds are less branched and shorter. Fibre-type varieties of the plant are grown as a high-density, high-strength, durable fibre that is used for making clothing and other textile products. Seed-type varieties of the plant are grown for their nutritional value and oil.
The fibre produced from hemp is stronger and more durable than flax fibre. It is commonly used for making ropes, twine, yarns, canvas, and other coarse fabrics. It can also be used to make paper, composites, insulation material, and biofuel.
The oils extracted from the hemp plant are used in food, cosmetics, and pharmaceutical products. Hemp oil contains the healthy omega-3 and omega-6 fatty acids and is an excellent source of linoleic acid, which can help lower cholesterol levels and support normal blood sugar metabolism. Hemp heart oil may also help alleviate the symptoms of rheumatoid arthritis, an autoimmune disorder that causes inflammation of the joints. However, more research is needed to confirm this. The plant's seeds can also be used to make a skin cream that is soothing and moisturizing.
Fiber
Hemp plants produce strong and durable fibers used in a wide range of textiles and composites. Hemp fiber has a natural elasticity that is superior to synthetics, and it resists moisture and mold. The plant's long bast fibers, which can be 3 to 15 feet in length, make for excellent ropes, canvas, and textiles. The plant's woody hurds have a high lignin content and are used in building materials such as hempcrete. The new composites and industrial products incorporating hemp fiber are a promising alternative to petroleum-based products.
Hemicellulose, a complex polysaccharide and one of the main components of the plant's cell wall, contributes to the strength, durability, and biodegradability of the fiber. Hemp fibers are also highly absorbent and a renewable resource for paper production, as well as providing an alternative to wood pulp and synthetic fibers.
During the growth cycle, hemp requires nitrogen and phosphorus rates similar to those of other grain crops, though the plant does better with high potassium (K) rates during the early development stages when it is developing fiber. Potassium rates should be based on soil test reports.
Once the plants have matured and are ready for harvest, they undergo a process called retting. This decomposition process separates the fiber from the plant's core. Traditionally, the field is left for retting (dew or water retting) for up to five weeks to break down the bonds between the outer long bast fibers and the shorter inner hurd fibers. Water retting is an alternate method that is quicker but requires clean water and must be carefully monitored.
Once the fiber is removed, it is then dried to a moisture content of 15% or less and baled. Hemp fiber is a sustainable alternative to cotton, silk, and wool and is suitable for use in clothing and rope. It is also being used in a variety of building materials, such as hempcrete, and has the potential to replace fiberglass insulation.
Oil
Hemp seeds contain high levels of polyunsaturated fat, particularly gamma linolenic acid (GLA), and omega-3 and omega-6 essential fatty acids. This makes it an excellent source of healthful fats and a complete protein. Hemp seed oil is a nutritional supplement and can be used as a cooking oil or eaten straight. Hemp oil is also used to make cosmetic products and as an ingredient in food.
In a study, researchers found that hempseed oil has anti-inflammatory properties and can be used to treat dermatitis. It is also rich in vitamin E, which acts as a skin moisturizer. Hempseed oil is often used in soaps, shampoos, and lotions.
Because it is so moisturizing, hemp seed oil can help prevent acne. It can also reduce redness and rashes from insect bites. It is a great base for essential oils, because it doesn’t block pores and allows the oil to absorb quickly.
It has an abundance of nutrients and health-promoting compounds, including vitamins, mineral salts, amino acids, phytosterols, and phytocannabinoids. These nutrients can help with heart disease, diabetes, inflammatory diseases, and even cancer.
The non-psychoactive cannabinoid, cannabidiol, is present in hemp plants. Studies have shown that cannabidiol has anti-proliferative and antiangiogenic effects on tumors.
Unlike marijuana, which has psychoactive cannabinoids, hemp has very little tetrahydrocannabinol (THC). THC is the main chemical responsible for cannabis’ intoxicating effects. It is also thought that cannabidiol may help protect against the aging process. Hemp seeds can be pressed to produce hempseed oil, which is rich in antioxidants. It is used in foods and cosmetics, as well as in paints and varnishes. It can also be used as a plasticizer and hardener in putty.
Hempcrete
Hempcrete is a sustainable building material made from the woody core of the hemp plant (Cannabis sativa L.) mixed with lime and water. It is an excellent alternative to concrete and other cement-based products. The bio-composite has a wide range of uses for new construction, renovation and remodeling, and as insulation in existing buildings. Hempcrete is one of the most breathable building materials, which allows it to regulate indoor humidity levels and prevent condensation and mold development. It also has good acoustic properties, and can provide an effective sound barrier between rooms.
Typically, Hempcrete is used as a insulation material for new buildings and for retrofitting or restoring older timber frame homes. It can be combined with other materials or act as the primary wall structure. It is cast around a timber frame or masonry wall, either hand-placed into temporary formwork or spray applied. The finished product can be coated with a variety of finishes, including timber and lime plasters and render.
When constructing hempcrete walls, it is important to use proper installation techniques and work with experienced contractors, architects, engineers, and structural consultants to ensure the safety and performance of the building. Hempcrete is stiff and more difficult to work with than traditional masonry and concrete, so a different set of skills may be required. It is also recommended that builders, tradespeople, and owner-builders receive training in hemp masonry before starting a project.
Hempcrete has low embodied energy and is carbon-negative throughout its life cycle. It absorbs carbon dioxide during its growth phase, releases zero greenhouse gasses during its production and use as a building material, and can be recycled in the event of destruction or removal. It is also easy to cultivate and requires less fertilizer, pesticides, and water than other crops. It is also a rotation crop, which helps to replenish depleted soil.
