Generally, early seeding dates are desirable for canola. This is especially true in regions with short frost-free periods or in arid areas where high summer temperatures can adversely affect flowering and pod development.

Typically, ‘early’ seeding occurs from late April to mid-May but varies by region. In most of western Canada, seeding after the third week of May puts canola at a higher risk for fall frost injury and loss of yield potential and quality. Seeding early helps reduce the overall risk of spring injury because severely damaged spring stands may have ample time to recover or be reseeded. Depending on hybrid maturity, seeding early may allow for an earlier harvest and possibly an opportunity to capitalize on fall marketing premiums. An early harvest can help reduce the risk of a mature crop being exposed to unfavourable harvest-time weather conditions.

Moisture from snowmelt in the spring can be critical for shallow seed placement which is required for maximizing emergence and seedling establishment. Missing this early-season moisture forces the crop to rely heavily on subsequent seasonal rain, especially in coarse textured soils with less water-holding capacity.

Yield penalties from planting late have typically been greater when seeding occurs in the last week of May or early June. Later-seeded crops are forced to mature when decreased growing degree days and daylight hours occur. This does not allow a canola plant to reach its full potential for yield.

Soil temperature greatly influences the rate of canola germination and emergence. Canola can germinate at temperatures as low as 2 to 3 °C; however, germination rates are lower and slower which results in plants emerging over a period of weeks. This can cause reduced and uneven stands. At 6 °C, close to 100% germination may occur within eight days.2

A row of green canola seedlings emerge in brown soil with trees and blue sky in the horizon.

Figure 1. Emerging canola seedlings.

A recommended soil temperature for fast germination and even emergence is 10 °C. Seeding at a soil temperature of 5 °C is a good starting point and is obtainable in early spring in western Canada.

Calendar date may not be a reliable indicator of soil temperature. The year-to-year and field-to-field soil temperature variation can be large. This is why it is important to check soil temperature on a field-by-field basis in the spring.

Steps to help improve survival rates for early seeded canola include:

  • Take soil temperatures twice a day (8:00 a.m. and 4:00 p.m.) for three days to determine an average soil temperature. The soil temperature in the seed zone should average at least 4 to 5 °C when measured over a 3-day period.
  • Plan your seeding date based on hybrid maturity. While seeding as soon as possible reduces the risk of fall frost damage for any hybrid, early seeding may be more critical for later maturing hybrids.
  • Utilize seed treatments offering protection from seedling and soil-borne diseases, and insects such as flea beetles and cutworms.
  • Be prepared to initiate weed, disease and insect control early. Late applications of these inputs may negate any potential gains from earlier seeding.
  • Seed shallow and do not chase moisture. Seeding deeper than 3.2 cm (1.25 inches) increases the risk of seedlings not emerging or being weak upon emergence.
  • Seed slower to help ensure precise seed placement.

Remember: Early seeding can lead to an earlier harvest, which reduces the risk of higher chlorophyll content in the seed and oil. Always wait to swath until the plants have reached 60% seed colour change. Canola should be straight cut when the moisture content is 10% or less.

Tips for improving the chance of a successful harvest if canola seeding is late include:

  • Target a seeding rate that establishes 7 to 10 plants per square foot (0.1 sq meter).
    • Lighter seeding rates result in thinner plant stands, increased plant branching and a delay in maturation. Seeding rates should account for potential plant loss due to spring stresses such as frost, flea beetles, cutworms, and weed competition.
  • Strive for proper seed placement.
    • The optimal planting depth for canola is 1.3 to 1.9 cm (0.5 to 0.75 inch). Seeding deeper can prolong emergence and increase the risk of seed and seedling diseases.
  • Choose an early maturing hybrid.
    • The DEKALB® brand has early maturing hybrids rated for straight cut and quick dry-down for harvest ease:
      • DEKALB® brand DK902TF TruFlex® canola is an ultra-early maturing hybrid with Roundup Ready® Technologies that provide glyphosate resistance.
      • DEKALB® brand DKTFLL 21 SC is an early maturing TruFlex® product (Roundup Ready® Technologies) and also has glufosinate tolerance.
      • DEKALB® brand DKLL 83 SC and DEKALB® brand DKLL 82 SC are early maturing hybrids with glufosinate tolerance. DO NOT HAVE GLYPHOSATE RESISTANCE.

Consult your Bayer Sales Representative or Market Development Agronomist with any product-specific questions.


1Pros and cons of early seeding. 2016. Canola

2Moran, M. Seed canola early for high yields. Ontario Canola Growers Association.

Web source verified 4/18/2024.

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