HEMP
Other Common Names Include:
None
Latin Name: Cannabis sativa L. subsp. sativa
Plant Family: Cannabaceae
Close Relatives: Marijuana (C. sativa L. subsp. indica), hops
Uses and Markets: Industrial (fibre, textile, biocomposites, paper, fuel); culinary (grain and oil); personal care products.
Production Life Cycle in Ontario
Annual
Hardiness Zone
N/A
Special Notes
Different cultivars are grown for fibre or seed. Industrial hemp is a controlled substance and may only be grown under licence from Health Canada. Only varieties named in the “List of Approved Cultivars”, published by Health Canada, are approved for planting in Canada. Information about varieties, licences and regulations may be obtained on Health Canada’s website or by contacting Health Canada’s Office of Controlled Substances at: Tel. (613) 954-6524 E-mail: hemp@hc-sc.gc.ca
Propagation method
Seeds
Greenhouse Seeding/Propagation Dates
N/A
Field Seeding Date:
Mid-spring. Early planting produces taller plants with higher fibre yields.
Field Transplanting Dates
N/A
Seeding/ Planting rate - Plant Density
Fibre: 200-250 plants/m2, grain: 100-150 plants/m2.
Between row spacing
15-18 cm
Optimal Soil temperature at planting
>6-10°C at a soil depth of 3 cm.
Fertility
No current Ontario fertility recommendations exist. Research and recommendations from outside Ontario do not necessarily apply to Ontario growing conditions. Hemp requires approximately the same fertility as a high-yielding crop of wheat. Research is continuing to define the exact nutrient requirements. Apply up to 110 kg/ha of nitrogen, depending on soil fertility and past cropping history. Click here for phosphorus and potassium application guidelines and for more information on specialty crop fertility.
Soil type
Well drained soils. Avoid extremely heavy or light soils.
Soil pH
6.0-7.5
Special requirements for growth habit
Small seeded crops require good seed to soil contact and finely prepared seedbeds.
Optimal Temperature Range
25-28 °C
Temperature sensitivity
Frost tolerant; seedlings are frost sensitive.
Irrigation requirements
Grain hemp requires significant water (125 to 175 mm) during flowering and seed set. While beneficial, irrigation is not normally used in hemp production.
Days to harvest
Depends on end use. Textile fibre: harvest at flowering approximately 70-90 days after seeding; Industrial fibre: harvest any time after flowering. Grain: harvest when approximately 70% of the seed is ripe (22-30% moisture content), 100-120 days after seeding.
Specialized equipment
None
Harvest
Harvest Scheduling
Single harvest
Hand harvest or machine harvest
Machine harvest; Standard field-crop equipment including sickle mowers, haybines, round balers and combines.
Quality parameters/grades:
No established grades. Quality is determined by the market.
Additional Harvest Notes
None
Post harvest
Special handling/curing
Retting to separate the bast fibres from the hurds or other plant tissues is usually done in the field. For storage, stalk moisture should be less than 15% at time of baling, and should continue to dry to about 10%. Grain hemp should be dried to 12 % moisture for storage.
Storage Conditions
Relative humidity (RH): Store in a cool/dry environment.
Temperature: Any temperature (fibre); Cool temperatures will extend storage life (grain).
Air Exchange: N/A
Duration: Indefinitely (fibre); 1 or more years under good storage conditions (grain).
Specific pests observed on this crop in Ontario (observations based on limited experience with this crop)
Insects and Invertebrates: European corn borer* (Ostrinia nubilalis), grasshoppers (Melanoplus spp.)
Diseases: White mold/hemp canker* (Sclerotinia sclerotiorum) botrytis head blight* (Botrytis spp.), , damping off/root rot (Fusarium, Pythium)
Other: Birds*
Other Potential Pests: The following pests have not been observed on this crop in Ontario. However, they are either significant concerns for closely related plants in Ontario, or are reported on this crop in other production areas. This is not a comprehensive list of all potential pests. Not all of these pests will necessarily survive Ontario’s climate, but could potentially survive in a protected environment (e.g. greenhouse, storage facility).
Insects and Invertebrates: Stem borers (e.g. Ostrinia nubilalis*, Grapholita delineana*), cutworms, slugs, white grubs, mites, caterpillar defoliators
Diseases: Gray mold *(Botrytis cinerea), root knot nematodes (e.g. Meloidogyne incognita, M. hapla)
Other: Parasitic plants attacking roots - broom rape* (Orobanche ramose)
*Indicates pests commonly mentioned as causing significant damage or economic loss to this crop in other regions.
Comments
More than 50 different viruses, bacteria, fungi and insect pests are known to affect the hemp crop. However, hemp's rapid growth rate and vigorous nature allow it to overcome the attack of most diseases and pests. Bird damage has been severe in some areas of Ontario and Manitoba. Significant losses in grain yields up to the entire crop have been reported. Crop rotation would appear to be a good cultural practice to avoid disease build-up until more is known about hemp's susceptibility to disease organisms. A 4-year rotation is recommended. Do not grow hemp on the same fields following canola, edible beans, soybeans or sunflowers. There are few to no pest control products registered on this crop in Ontario.
Police checks must be completed for a commercial licence to grow hemp and must be renewed annually. Licensing is done by the Industrial Hemp Regulations and the Therapeutic Products Directorate of Health Canada.
Click here for a more comprehensive production guide.
- Asbil, W, L. Bell, and L. MacGregor. 2008. Assessments of agronomic methods to improve the processing quality of hemp grown for fiber in eastern Ontario. Kemptville College, University of Guelph
- Baillie, C . 2004. Development of plant fibre composites for structural applications. OMAFRA - New Directions Program
- Baker, J. 2006. Biofibre genetic profiling and breeding program. OMAFRA - New Directions program
- Ontario hemp alliance. 2008. Hemp breeding and national hemp grain variety characterization/ development project
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- Robinson, B. 1935. Hemp. United States Department of Agriculture
