Hemp Fiber Production & Processing

Field Production

Hemp belongs to the Moracea family (the Mulberry family) and the commercially cultivated species are Cannabis sativa.  Notes on hemp growing, yields and structure:

  • Sowing:  industrial hemp is usually seeded at approximately 1,000 to 1,350 seeds per hectare (60 to 80 kg of seed/ha.)
  • Growing:  the growing season is usually 95 to 115 days in temperate climates from sowing to harvest.  Usually hemp stalks are 1.5 to 2.5 m high with stalks 4 – 10 mm in diameter.  In some cases, the plants can grow as high as 3- 4 m high and the stalks as thick as 20 to 25 mm.
  • Stalk Yield: is usually 6.5 to 12 tonnes per hectare.
  • Fiber Yield:  23 to 35% of stalk mass under ideal growing and processing conditions and depending on the variety of plant.  Approximately 1.5 to 4.2 tonnes of fiber per hectare.  Note: 1.5 to 4 times higher fiber yield than flax. Only 10 to 20% of cotton fiber yields.
  • Fiber Bundles:  can be as long as 100 to 300 cm.

Processing

Fundamentally, hemp fiber extraction for technical fiber purposes involve the following main steps:

  1.  Retting Harvested Fiber: Keeping the baled fiber in the field for some wet period of time to instill some bacteria-induced delaminating of the bast fiber from the core; once retted, the middle lamella is substantially degraded and the woody plant core is dry and brittle.
  2. Decortication: Processing the field feedstock via special machinery — the Decorticator — to separate the outer bast fiber from the inner core hurd fiber
  3. Refinement of Bast Fiber: Processing the Bast fiber after decortication through special machinery to:
    • Remove non-structural fiber
    • Align the fiber
  4. Surface Treatment & Sizing of Fiber: Using special machinery, as required for applications

See how we processes fiber using our HempTrain® production machinery. Learn More.