The Potential of the Hemp Crop in Scotland

Is the hemp crop about to become mainstream in Scotland? A recent report Advancing a Sustainable Scottish Supply Chain for Industrial Hemp and Co-Products funded by IBioIC and Scottish Enterprise, and delivered by SAC Consulting, identified the potential of this highly versatile crop as a profitable break crop for farmers, as the source of a wide range of natural products for industry and as an excellent method of carbon sequestration.

The world hemp market is projected to quadruple by 2030 as demand increases for biobased materials to replace products derived from fossil fuels. Industrial hemp is used across sectors such as agriculture, automotives, bioenergy, construction, food and beverages, furniture, paper, personal care, recycling, and textiles.

Fibre crops were once widely grown in Scotland, but current production is small scale with niche enterprises mainly harvesting hemp seeds for health and food markets. The study sought to establish a co-op to grow industrial hemp at large scale, producing hemp fibre and shiv, largely for the house building, insulation and soundproofing market, as well as exploring new product opportunities such as composted hemp shiv as a high value crop growing medium.

Trials confirmed that hemp crops should grow well on Southeast Scottish arable farms requiring warm soil and adequate moisture at sowing in late April/early May. Once established, growth is rapid with 100 days between sowing and cutting in early August, with crops up to 2-3m in height. It then relies on retting, a 4–6-week process that requires proximity to the soil and moisture for soil microbes to break up lignin in the fibre before rowing up and baling when the crop is dry. Timing of cutting and baling are critical to processing quality as is keeping the bales dry through transport and storage.

Primary processing, decortication and cleaning, involves mechanically removing the ‘bast’ fibres from the hemp stem’s woody core known as ‘shiv’ or ‘hurd’, finishing with bales of short fine fibre for manufacturing insulation products and milled shiv used for insulation boards, hempcrete or animal bedding and briquettes for wood burning stoves.

The study assessed the feasibility of setting up a grower co-operative supplying a decortication and cleaning plant, processing up to 12,000 tonnes per year (2,000 ha x 6 tonnes per hectare), in turn supplying manufacturers and retail distributors. Capital cost of the decortication and cleaning plant is estimated at around £5 million, preferably with significant investment from farmers to obtain added value from the hemp crop.

Barriers to entry include restrictive licensing requirements for growing hemp, limited demand from the construction industry for natural products, a lack of incentives to pump prime the development of a hemp grower co-operative and the establishment of processing facilities. Establishment of a bio-fibre steering committee, a clear policy framework and industry incentives for bio-fibre, and a government-backed carbon credit platform to reward these crops’ contribution to the circular economy would greatly aid the establishment of a network of hemp and other fibre crop co-ops in Scotland.