We didn’t get involved in hemp production this year, but a few years ago Ron wrote up a fact sheet for farmers who are considering growing hemp in Manitoba. If you’re thinking of growing hemp in 2010, this is a good place to start. Feel free to give Ron a call at 204-433-7189 or 204-346-2064 for more advice and information.

TIPS ON HEMP PRODUCTION

SEEDING

Equipment

• Hemp can be sown with the existing conventional equipment such as press drills, hoe-press drills, diskers and air seeders.
• When using air seeders, attention must be paid to the blower speed. Slow fan speed down till it plugs to find out where to start from.
• Packing can improve emergence through increase soil to seed contact.
• Seeding in wet conditions can result in poor germination and excess packing of soil. It is better to wait for good seed bed conditions then to seed into soil that is too wet.

Seeding Date

• Hemp seedlings are tolerant of light frost down to –5 C, so planting between May 25 and June 5 depends on spring temperatures.
• Optimum germination occurs at 8 C.

Seeding Rate

• 22 lbs./acre for seed production.

Maturity

• 110 to 125 days for Felina 34

Depth

• Seeding depth should be as shallow as possible while still being into available moisture. This can generally achieved between ¾” and 1¼”.
• Deeper seeding results in delayed and reduced emergence. This unevenness of stand increases amounts of lodging and creates an uncompetitive stand, allowing more weeds to flourish.

Row Spacing

• Broadcast or in 6” to 10” row spacing, increasing spacing will result in more weed pressure.

SOIL FERTILITY

• 80 lbs. of Nitrogen (includes soil test plus fertilizer). Excess Nitrogen can reduce yields and stalk strength, which increases lodging. Excess Nitrogen can increase the chance of leaching of nitrates into the water table, unnecessarily raise producer’s production costs and delay maturity.
• Phosphate application should be in the 25 to 35 lbs./acre range with the seed. Hemp is recognized as high phosphate user.
• Potash needs to be added on soils showing low in potash.
• Sulfur trials in Dauphin have shown no response to addition of sulphur.

WEED MANAGEMENT

• Generally hemp forms a thick canopy after the five-leaf stage that suppresses most weed growth. In cases where the vigor is reduced due to standing water, weeds may be able to out-compete the hemp. Of particular concern are Wild Mustard, Wild Oats, Red Root Pigweed, Lambsquarters and Wild Buckwheat.
• Hemp is sensitive to herbicide drift or residues. Triazine residues have caused problems for hemp crops well after the normal waiting period has elapsed. Hemp following a corn crop that had many atrazine applications should be cautioned, MCPA and 2,4-D will cause injury to hemp.
• Control of weeds can be achieved through field choice, pre-seeding tillage, shallow seeding, and packing after seeding. To ensure a clean seed bed, pre-emergent or pre-plant applications of glyphosate has proven effective.

DISEASES

In general, fungi cause most diseases.

• Sclerotinia sclerotiorum – Hemp Canker This disease occurs in wet soil and attacks many plants. Symptoms begin as water soaked lesions on stems at the base of the root and along the stem. These lesions collapse into cankers and eventually kill the plant. The disease is transmitted by sclerotia that remain in infected residue. Mustard and volunteer canola are the major alternate hosts for Sclerotinia sclerotiorum.
• Botrytis cinerea – Grey Mold Botrytis is the main cause of damping off in seedlings. During conditions of high humidity (>60%) and temperatures ranging around 20-24C, the disease can spread quickly. The best methods of prevention are planting disease free seed, and rotation to cereal crops.
• Fusarium species In Alberta, it has caused stalk cankers and root rot.

INSECTS

• Hemp is highly pest tolerant. Insect pest of commercial hemp can be divided into two main groups; stem borers and leaf grazers. The most common stem borer in the prairies to date has been the European Corn Borer (ECB). The hemp borer and flea beetle have also been known to infect hemp here in Manitoba in past. The worst leaf-eating pests have been caterpillars, primarily Bertha Army Worm. Cutworms, grasshoppers, lygus bug, aphids, plant bugs, and thrips are all known to infest hemp, but damage has been very minor.

BIRDS

• In areas where sunflower or corn production is limited because of bird predation, hemp will likely be seriously limited also.

GRAIN HARVESTING

• The best approach to harvesting has been to straight cut the upper portion of the crop, with the MacDon header 2-3 feet below the top of the crop. Both conventional combines and rotary combines will work, but the operator must always watch the rotating parts to avoid wrapping the tough stalks. There are a number of adjustments for combines to minimize the loss and damage to the seed and fiber, and damage to machinery:
• Set cylinder speed to 400-600 rpm (to start with) to prevent cracking and peeling of seed. Care should be taken to avoid dehulling in the combine. When the seed is cracked or broken, the oils begin to go rancid. Damaged seed will incur a significant price discount
• Sieves should be open for about ¼ inch and adjust from there
• Just enough air to blow out chaff and green but not mature seeds.
• Set concave open half open
• Place protective shields along exposed or turning parts of the combine to avoid testing the world’s strongest natural fiber against your machines
• Disconnect straw chopper, as we do not want to damage or lose too much of the fiber
• Place dividers in front of the tires or minimize tire width
• Carry a fire extinguisher on your combine—one with a long wand and a pump so hard to reach areas can be reached. Hemp can wrap or plug in portions of unprotected machinery, creating the potential for fires
• Stripper Headers have only worked so far on extremely lodged crops
• Draper tables on headers have been quite effective for moving long stalks evenly into the feeder house of the combine

CLEANING OF EQUIPMENT

Section 17 of the Health Canada “Regulations on Industrial Hemp” requires:

The cleaning of equipment that is used to harvest the industrial hemp after each use to avoid inadvertent dissemination of industrial hemp. The cleaning is similar to CSGA seed grower cleaning requirements. Adequate cleaning of combines will involve “blowing” the combine out by increasing wind speed and opening all accessible auger gates, and by dislodging any crop debris and seed which may have accumulated on frame parts on the undercarriage of the combine – this should be done before the combine leaves the hemp field. Other areas in which seed tends to accumulate in the header or in the combine can be vacuumed using a Shop-Vac.

• Thorough inspection and removal of all fiber that has accumulated after harvest is essential before continued use of machinery to avoid damage to the bearings etc. and the potential of fire.

DRYING/STORAGE/CLEANING

• Straight cut seed can come off the field at 15 to 20 % moisture, so immediate unheated aeration is necessary if the seed is going to sit for any length of time. At the higher moisture will need to have a drier to dry it down.