What is Hemp Fiber? Properties, Advantages and Disadvantages.

When harvesting grain, it’s best to start when the seeds start to shatter. At this point, around 70% of the seeds will be fully mature, and the rest of the plant will still be green. It’s better to keep the grain’s water content below 20%, even though it can go over this mark. Many recommend using grain combines for harvesting, with settings similar to grain sorghum. However the long stems can be a challenge, so some use PVC pipes to prevent entanglement. To improve the process, keep the header high to reduce the amount of stem going through the combine. Dry plants can create a fire hazard due to dust. To reduce this risk, move the grain at low auger speeds or use conveyor belts. Proper methods for harvesting, processing, transportation, and storage are crucial for grain crops, including hemp, to prevent spoilage and get the best value. Hemp grain is delicate and needs careful handling during harvest, storage, and transport. Use a grain drying facility, and start drying within 1.5 hours of harvest. Keep the grain temperature below 100°F to avoid overheating. Hemp grain contains 29-34% oil, with 15-25% of it being alpha-linolenic acid, similar to flax but with less oil and alpha-linolenic acid content. For fiber production, cut hemp between early bloom and seed set when lower leaves are yellow. Windrows are baled at 12% moisture and then processed to separate bast and Hurd fibers. Bast hemp fibers are concentrated in the “bark” of the stem, while shorter hard fibers with more lignin are found in the rest of the stem. Wider diameter stems are preferred for fiber. You can use a multi-cut combine or separate passes for grain and fiber harvesting.
Traditionally, hemp was left in the field for up to five weeks after harvesting for a process called dew retting, which breaks down the fibers. However, this method depends on the weather and can affect fiber quality negatively. An alternative to dew retting is water retting, which requires a lot of clean water that should be treated before being discharged. Another approach gaining popularity is mechanical fiber separation, which doesn’t require retting, or potentially using an enzymatic treatment.