5.3.1 Harvesting for technical applications

Harvesting with specific machineries
Machines for harvesting fibre hemp for technical applications (insulation in construction, composites for automotive industry) are adapted to cope with the very strong fibres and to get good feedstock quality for further processing. In this process, the stalk is cut into pieces of 60 cm in length to avoid wrapping around the rotating parts of the machineries, both during harvesting and further processing (§6.1). At harvest, the hemp stalks ('hemp straw') are placed on windrows (Figure below, left) for retting purposes (§5.4). A windrow is a row of harvested crop for the purpose of further processing.

Flowers, leaves, seeds
The harvesters also allow separate harvesting of flowers and leaves (Figure below, right). These can be harvested for further processing. Seeds are actually not harvested in the Netherlands so far: in order to harvest seeds, the plant needs to be harvested around mid-September in the northern part of the Netherlands, after which the weather is often too wet to allow a correct drying of the stems. In the southern part of the Netherlands, the seeds are ripe by early September and the weather appears to be more favourable to seed production.

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Harvesting hemp for fibre for technical applications; stalks are placed on windrows for retting.

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Harvesting machine for fibre hemp, where flowers/leaves are harvested separately. Photos HempFlax.