Seeding and Soil Preparation
Choosing a Seed Source
Planting certified seed is good insurance that the seed will have acceptable genetic and physical purity. Seed canola should have a rating of double zero because both characteristics (low erucic acid and glucosinolate) are important criteria for canola in the market. Use only high quality seed that has not been contaminated by other rapeseed and that does not have a double zero rating.
Soil Type and Preparation
Winter canola grows well on soils with good surface drainage and minimum likelihood of standing water. Fall-sown canola grown on heavy clay soils may experience root heaving in the spring, so such soils should be avoided for winter canola. Winter canola grows and overwinters best on well-drained soils like sandy loams. Snow cover helps canola over-winter in northern areas.
Before planting canola, treat fields with glyphosphate or other suitable chemical to control perennial grasses. Do this in the fall in preparation for spring seeding, or in the fall or throughout the summer in preparation for fall seeding.
A well prepared seedbed is essential for promoting emergence, achieving desired stands, and decreasing weed pressure. Prepare a good seedbed similar to that for small grains, then cultipack to ensure better seed-soil contact. The final tillage operation should be less than a week before planting to kill weed seedlings and move soil moisture into the seeding depth area. No-till has not been a successful technique for canola so far.
Canola responds well to nitrogen fertilizer, with optimum yields occurring with 125 lbs per acre of actual N. Apply broadcast and incorporate at seeding time for spring canola along with P, K, and S as indicated by a soil test for small grain. For winter canola, use a starter nitrogen application of about 20 lbs./acre and topdress with about 125 lbs./acre in the spring prior to regrowth. Sulfur is recommended for northern Michigan at the elemental rate of 20 lbs./acre. This can be applied as either ammonium sulfate, potassium sulfate, potassium-magnesium sulfate (sul-po-mag), or slag. As always, determine fertilizer according to soil test results. Send soil to MSU for a soil test.
Spring - Begin to plant spring varieties as soon as soil and weather conditions permit (soil temperatures 45 to 50 degrees F). This normally occurs during late April in southern Michigan and mid-May in northern Michigan. Like spring barley, seed canola as early as possible for best yields; however, unlike barley it can be inured by a hard frost. Since it requires 95 to 100 days to reach maturity, plant early enough to reach maturity and dry down for harvesting prior to wet periods in late summer or fall.
Winter - Plant winter varieties between August 20 and September 10 in the Upper Peninsula and between August 20 and September 10in southern Michigan. It is important that enough fall growth occurs to allow canola to go into the winter with adequate root reserves. This generally equates to about the 6- to 8-leaf stage, or more accurately a crown size of ⅜- to ½-inch size diameter. Excessive fall nitrogen and planting too early can cause crown extension and lead to reduced winter hardiness.
Seed both spring and winter canola at the rate of 5 to 7 pounds per acre.
Method of Planting
The use of a grain drill with a small seed attachment and row spacing between 6 and 14 inches is preferred for canola planting, seeding at a depth of 1/4 to 1/2 inch. Broadcast spreading followed by cultipacking is acceptable for canola planting but may produce an uneven stand due to poor seed placement.
BEWARE OF HERBICIDE CARRYOVER
Herbicide from the last season's crop can damage canola. Here are some commonly used herbicides that may affect canola: Accent, Ally, Amber, Assert, Atrazine, Banvel, Basis, Beacon, Broadstrike, Broadstrike+Dual, Broadstrike+Treflan, Classic, Command, Glean, Harmony, Exceed, Permit, Prowl, Pursuit, Pinnacle, ProvA, Reflex, Sonalan, Sencor/Lexone, Scepter, Treflan and Trifluralin combinations, and Tordon. As always, consult the manufacturer for more specific information about herbicide carryover problems with canola (carryover information may be listed under rapeseed or Brassicas).