In Canada, quality standards have not been fully determined for fibre crops. Fibre quality requirements will have to be developed and refined as processors begin to find out qualities that enhance their end product. Some general guidelines include:
- Moisture Content – Aim for 16 % or below. This has proved very achievable over the years, but watch for wet patches when baling, e.g. on headlands and ensure safe storage. Mold in bales is not acceptable; however, baling hemp straw below 10% can be detrimental to fibre integrity resulting in brittleness and loss of yield.
- Weed Content – A good stand of a fibre type hemp variety allows very little weed competition to survive, but in conditions of poor establishment, weeds can be a problem. If practical, avoid baling any patches of weeds and do not include weedy bales, as they cannot be processed and it contaminates the finished product. Organic production may lead to higher weed-contamination of hemp straw.
- Wild oats and cereal straw is not acceptable in the bales. Avoid areas in the field that have excessive volunteer cereals. Under conventional crop production practices, grassy weeds can be easily controlled chemically (i.e. Assure II). Broadleaf weeds cause fewer problems for hemp straw processors as they do not have as much fibre and break down easier. Bales with unacceptable weed contamination will be not accepted and delivery penalties may apply.
- Stones – These can cause damage in the factory. Tailor field operations to avoid baling up stones. Deductions will be made for stone contamination, in extreme cases there may be rejections. Stack bales so stones are not imbedded in the bottom of the bales.
- Plastic debris are not a common problem, but one that causes major difficulties for some fibre buyers. Take care to ensure fields and particularly gateways are clear of all plastic and other detritus.
- While bales tied up with sisal twine are often favoured, plastic net wrap or twine is also acceptable by some fibre processors. Inquire with hemp fibre contactor about processor’s preferences.
Hemp Fibre Grading
No standardized hemp fibre grading system is currently in use in Canada. Future fibre buyers will take into account several parameters including fibre length, strength, moisture content, cleanliness, degree of retting (color) and visual appearance; therefore, grading standards that could be consistently used and accepted by different hemp processors and customers across the country will have to be developed. Initial grading will be done at fibre processing plants as a part of the quality assurance system to meet clients’ requirements. Specialized reference lab(s) verifying fibre quality and consistency are also warranted.