Row Width
Ontario spring canola is commonly grown in 19 cm (7.5 in.) spacings. Row widths of 38 cm (15 in.) are also appropriate. Research conducted in Alberta indicates that row closure on 35.5 (14 in) cm row spacings may take a day or so longer than on narrow rows. Yield on 35.5 cm rows was not significantly different than yield on 19 cm rows.
There may be up to a 10% yield loss when canola is grown on 76 cm (30 in.) row spacings. Wide row canola stands may be more variable because the plants will produce many branches and have a longer flowering period. The seed in pods on the first branches may mature long before seed in pods on the last branches. This can make it difficult to time fungicide applications and harvest. Canola plants grown on wide rows may also have very thick stalks which can introduce cutting challenges at harvest.
Seeding Equipment
The goal is to seed spring canola at a rate of 80 to 120 seeds/m2 (320,000 to 485,000 seeds/ac). Box drills, air drills and air seeders are all commonly used to seed canola. Row unit planters equipped with canola plates achieve more precise rate control and singulation resulting in more uniform stands and are used to plant winter canola at low seedings rates. More precise seeding equipment, such as a planter, could reduce seed costs but seed savings alone may not justify costs associated with a new planter or potential changes to fertilizer application methods. Low seeding rates work well in winter canola since winter survival is better at low populations. In spring canola higher seeding rates are recommended to mitigate the risk of stand loss from early season insect pests.
Achieving the target canola seeding rates can be a challenge with some older conventional style drills. Calibrate seeding equipment before heading to the field. Ensure that each of the drill’s seed cup openings is set the same. Slow-speed sprockets and/or seed bulking agents can be used with conventional drills to fine tune seeding rates. Bulking of seed with pelletized elemental sulphur, monoammonium phosphate (MAP), MicroEssentials Sulphur + Zinc (MESZ), or corn cob grits are options for improving seeding rate accuracy. Consult the fertilizer section of this resource to understand safe rates of these seed-placed fertilizers. Do not use other fertilizers, or high rates of these starter fertilizers, with canola seed due to risk of reduced seed germination and emergence from salt toxicity.
Broadcast seeding of canola should only be done where there is no option of using a seed drill or other more precise seeding equipment. Broadcasting can be effective when seeded early in spring and where adequate moisture is sustained throughout the germination and emergence period. Some producers broadcast canola seed with fertilizer onto a prepared seedbed. The advantages of broadcast seeding are time savings and low cost. The major disadvantage of broadcast seeding is uneven planting depth and seeding uniformity. Higher seeding rates (10%–15% increase) are often required for broadcasting compared to drilling. Frost injury is also a risk with an early seeding date. Good seedbed preparation ahead of broadcasting followed by harrowing or packing helps to keep seed depth constant and ensure good seed-to-soil contact. Broadcast stands can be inconsistent in dry years.
Seeding Depth
Rapid and uniform emergence is desired. Sowing depth has a major effect on seedling vigour. Seed 1.25–2.5 cm (0.5–1 in.) deep if there is adequate moisture, and deeper if necessary to plant 0.6 cm (0.25 in.) into moisture. Do not plant deeper than 4 cm (1.5 in.). Emergence of seed planted at 4 cm can be decreased by 50%–60% compared to planting at optimum depth. Seeding into moisture will support uniform emergence and growth that will help with timing of weed control, pesticides, and harvest. Dry conditions at seeding or in the following week can increase seedling mortality significantly.
Seeding Rate
Canola is considered a “plastic” plant in that it adjusts to its surrounding environment and can compensate for wide variations in population with very little effect on final yield. The optimum plant stand is 55 to 85 healthy plants/m2 (5 to 8 plants/ft2), however, a stand of 55 plants/m2 has the same yield potential as a stand of 215/m2 (20 plants/ft2). In a higher density stand, the canola plants will produce fewer branches. Higher density stands may be more uniform in terms of pod formation and maturation, where lower density stands with more branching may have a longer flowering period and take longer to mature. Dense populations may have thinner stalks and increased lodging but are more competitive with weeds and may be preferred where high flea beetle damage is expected. When moisture is limited, low density stands may not be able produce adequate yields.
Seed spring canola at a rate of 80 to 120 seeds/m2 (320,000 to 485,000 seeds/ac). The average seeding rate for spring canola is 5–6.2 kg/ha (4.5–5.5 lb/acre). Adjust seeding rates for the expected emergence rate in each field based on factors such as soil type, weather, planting equipment and planting date. Emergence and seedling survival will be influenced by temperature, seeding depth, soil type and seedling diseases. In a survey of canola fields in western Canada, only 40%–60% of planted seed typically produced viable seedlings. Similarly, in Ontario it is expected that under good conditions a 75% emergence rate is reasonable but under average conditions around 60% emergence is a reasonable reference point for seeding rate calculations. Use seeding rates at the high end of the suggested range on soils prone to crusting, when seeding under cool conditions, or when seeding very late.
Canola seed size can vary greatly between varieties. Seed size has not been found to influence rate of emergence or yield. Calculate the target seeding rate in kg/ha (or lb/acre), using the 1,000 seed weight in grams found on the seed tag. Include the percent germination on the seed tag, and the expected emergence in the given field in the seeding rate calculation.
Seeding Rate Example
Metric
Seeding rate (kg/ha)
= (desired plant population/m² x 1,000 seed weight in grams ÷ seedling survival rate) ÷ 100
Imperial
Seeding rate (lb/acre)
= (desired plant population/ft² x 1,000 seed weight in grams ÷ seedling survival rate) ÷ 10.4
Seedling survival (final stand)
= % germination (on seed tag) x % expected emergence
Sample Calculation
Using seed size of 5 g/1,000 seeds, 90% germination guarantee on No.1 seed and 75% expected emergence
Seedling survival
=0.9 x 0.75
=0.675
Seeding Rate (kg/ha)
= 75 plants/m² x 5 g ÷ 0.675 ÷ 100
= 5.6 kg/ha
Seeding Rate (lb/acre)
= 7 plants/ft2 x 5 g ÷ 0.675 ÷ 10.4
= 5.0 lb/acre