A Maritime Industrial Hemp Product Marketing Study

Appendix D

Agronomic Backgrounder

by Peter Dragla

D1. A Grower’s Guide to Hemp

PLANT DESCRIPTION: Hemp (Cannabis sativa L,) is an annual, herbaceous plant with a slender stem, ranging in height from 4 to 15 feet and a diameter from 0.25 to 0.75 inches. The innermost layer is the pith, surrounded by woody material known as hurds. Outside of this layer ‘is the growing tissue which develops into hurds on the inside and into the bast fibres on the outside. The stem is more or less branched, depending o n the crop density. When sown thickly the stems do not branch. The leaves are of a palmate type and each leaf has seven to eleven leaflets, with serrated edges. The strong tap-root penetrates deep into the soil. However, if the soil conditions are unfavorable, the main root remains short, while lateral roots become more developed.

SOILS: Hemp can be grown on a wide variety of soil types. Hemp prefers a sufficiently deep, well-aerated soil with a pH of six or greater, along with good moisture and nutrient holding capacity. Poorly drained soils, however, are not recommended as excess surface water and heavy rains can result in damage to the hemp crop. Hemp is extremely sensitive to flooding and soil compaction.

SOIL PREPARATION: A fine, firm seedbed is required for fast, uniform germination of hemp seed. Conventional seedbed preparation and drilling are probably ideal. The seedlings will not emerge uniformly if the seed is placed at a depth greater than two inches. No-till systems can also be used with good results, but may be more vulnerable to erratic emergence depending on the growing season.

NUTRITION: To achieve an optimum hemp yield, twice as much nutrient must be available to the crop as will finally be removed from the soil at harvest. A hemp field produces a very large bulk of plant material in a short vegetative period. The nitrogen uptake is most intensive the first six to eight weeks, while potassium and in particular phosphorous are needed more during flowering and seed formation. Hemp requires 105 to 130 lbs/ac (120 to 150 kg/ha) nitrogen, 45 to 70 lbs/ac (50 to 80 kg/ha) phosphate and 52 to 70 lbs/ac (60 to 80 kg/ha) potash.

GROWING CONDITIONS: Hemp prefers a mild climate, humid atmosphere, and a rainfall of at least 25-30 inches per year. Good soil moisture is required for seed germination and until the young plants are well established.

WEED CONTROL: Hemp is an extremely efficient weed suppresser. No chemicals are needed for growing this crop. A normal stand of 200 to 300 plants per square metre shades out the competition, leaving the fields weed-free at harvest for the next crop.

TIME OF SEEDING: The best time to seed hemp should be dictated by the weather and soil conditions, rather than the date on the calendar. Hemp can be seeded as early as two weeks prior to corn provided that soil conditions are optimum. However, seeding should not begin until soil temperatures have reached a minimum of 42-46 fF (6-8 fC), Hemp seed germinates within 24 to 48 hours, and emerges in 5-7 days with good moisture and warm temperature.

PLANT POPULATION: High yields of high quality fibre can be achieved with proper plant density. Seeding rates of 250-400 viable seeds per square metre are probably ideal, depending on soil type, soil fertility and cultivars. The seed or grain production will require lower seeding rates.

BREEDING CHARACTERISTICS: Hemp is a dioecious plant. However, there are three classifications of varieties. Monoecious varieties have both male and female flowers developing on the same plant. Dioecious varieties have distinct male and female plants. Female predominant varieties are obtained by pollinating dioecious females with monoecious pollen.

CULTIVAR TYPES: There are two types of hemp based on their use. These are fibre cultivars and seed cultivars which have shorter stalks, larger seed heads and may have numerous branches (seed contains 30-35% oil). Both types have low-THC content of less than 0.3%.

ROTATION: Hemp can be grown on the same land for several years in succession but rotation with other crops is desirable. Hemp responds well to soil from most preceding crops. It is also possible that introduction of hemp in a crop rotation might improve the soil health Our observation in 1996 showed that hemp may significantly reduce the population of soybean cyst nematodes.

HARVEST: Harvesting of hemp for high quality fibre occurs as soon as the last pollen is shed. Harvesting for seed occurs 4-6 weeks later, when 60% of the seed has ripened. Fibre hemp is normally ready to harvest in 70-90 days after seeding. The end use of the product may have a significant impact on the harvesting method. Kenex Ltd. is developing a harvesting system that will be compatible with the new processing technology. For fibre production the crop will be cut, dew retted in the field, baled and stored or processed.

RETTING: The bast fibres are obtained by retting a microbial decay of pectin, the substance that glues the fibres to the woody core of hemp stem together. Retting is carried out in the field and depending on the weather it takes 12-18 days to be completed. During retting, the stems need to be turned one or two times in order to allow for even retting, since the stems close to the ground will remain green while the top ones are retted and turn brown. Retting is complete when the fibres turn golden colour and separate easily from wood in finer fibres.

YIELD: Based on yield data from 1995 and 1996 along with preliminary estimates for 1997 field expectations are between three to five tons of baled hemp stalks per acre on well-drained loamy soils in Southwestern Ontario.

STORAGE: For storage, the moisture content of hemp stalks should not exceed 15%. The bales can be stored for a long time in dry places which could include storage sheds, barns or any other covered storage.

D2. Other Sources of Information

We know hemp can be grown in various regions of Canada. It is not clear yet, however, what yields and economics can be expected under various commercial-scale growing conditions. To quote one contact, “It is the oldest grown crop we know nothing about – a substantial part of the literature cannot be substantiated”.

The hemp-marijuana lobby effort has generated volumes of information. Much of it can be found on the Internet. The reader must, however, be aware that like any information source, care must be taken to understand who posts such information and what are there motives in doing so. You will literally spend days searching the Internet given the amount of literature and news groups available.

The following reports were found to be useful and have been sourced for this study. They contain information from agronomics to economics. For your convenience, we have also listed their Internet websites. Please note some of these reports require the software application, Adobe Acrobat Reader, as they are archived in PDF format:

Government of Canada: Report on Hemp by Gordon Reichert Bi-weekly Bulletin December 16, 1994 Vol. 7 No. 23: www.psibear.mb.ca/reichert.htm

Health Canada Commercial Production of Hemp: Fact Sheet (March 1998): www.hc-sc.gc.ca/hpb-dgps/therapeut/htmleng/hemp.html
Manitoba Agriculture Hemp Factsheet: www.gov.mb.ca/agriculture/facts/hemp/bko01s01.html

Ontario Ministry of Agriculture, Food and Rural Affairs Hemp Factsheet (OMAFRA):www.gov.on.ca:80/OMAFRA/english/crops/facts/hempprod.htm
Commercial Hemp Cultivation in Canada-An Economic Justification by David Marcus (as found within the homepage for the North American Hemp Council): www.naihc.org/

Hemp Factsheet by A. Oliver and H. Joynt of the British Columbia Ministry of Agri-Food: www.agf.gov.bc.ca/croplive/plant/horticult/hemp/hempinfo.pdf

The Economic Impact of Hemp In Kentucky, July 1988, Thompson, Berger and Allen, University of Kentucky: www.hempgrowers.com/frames.html
Industrial Hemp: Global Operations-Local Implications, July 1998, Valerie Vantreese, Department of Agricultural Economics, University of Kentucky: e-mail address: vvantree@ca.uky.edu

An Evaluation of Opportunities in the Atlantic Agri-Products Sector for Hemp, March 31, 1997, Scovil Associates and Dr. Jim White of InfoResults Ltd., www.novasight.com/AAPC/