Planted between March 15th and the last week of May in straight lines or scattered, 35 and 40 kilograms of hemp seed are planted per hectare. Growers have different varieties available to them depending on the desired harvest (with or without seeds).
Between 100 and 130 days.
Hemp grows rapidly (3 to 5 meters) and quickly smothers other unwanted plants around it so no weeding is needed and no phytosanitary treatments are necessary. Any rare parasites are removed by hand as soon as they appear.
Based on the desired production, the plant is harvested at the end of August for a partial use without shives and at the end of September if the entire plant is used. With a combine-harvester, the grain can be harvested while maintaining a 20% humidity. In this case, cleaning and drying are also needed to conserve the hemp’s dampness at about 10%.
Reaping is done with a double-bladed reaper. The straw is then swathed, pressed and baled in workshops where the fibers are removed. Baling must be done as quickly as possible to prevent the straw from retting too much.
Transformation by mechanical defibrillation
In the past, hemp was retted in water pits and then scutched like linen. Today, the tow (external cellulose fiber) is separated from the shive (the central, soft part of the stem) by mechanical defibering, a process that uses little energy and no chemical treatments thanks to high-performance industrial equipment and technical know-how. The very light shive is 65 to 70% of the stem’s total mass. It has cellulosic and lignosic components and must be dusted, sifted and sorted depending on its final use.