March Agronomy Update 2025
Optimising Canola Establishment with Varying Seed Size
Selecting the right canola seed size is a critical factor in achieving strong crop establishment and maximizing yield potential. Research from the Grains Research & Development Corporation (GRDC) shows that larger seeds generally have more stored energy, leading to improved germination, stronger early growth, and better seedling vigor. This advantage can be particularly beneficial in challenging conditions, such as dry soils or deeper sowing.
However, smaller seeds can still produce good results when managed correctly. They may require shallower sowing and may benefit from adjustments in seeding rates to compensate for potential lower emergence rates. Well managed seeding techniques and optimal nutrition are key to achieving uniform establishment regardless of seed size. Refer to your agronomist for more detail and information on fertiliser use to minimise toxicity.
We have been advised that several seed companies may have commercial seed lots of differing seed size. It will be important to check the bag for seeds per kilogram (seeds/kg) to best target your desired plant population.
- Seed Size and Seeds/kg:
Canola seed sizes vary, with larger seeds having fewer seeds per kilogram and smaller seeds having more. Example below.
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- Small: ~300,000 seeds/kg
- Medium: ~250,000 seeds/kg
- Large: ~200,000 seeds/kg
Factors Affecting Seeding Rate:
Seeding rates are also influenced by factors like target plant density, germination percentage, and field establishment conditions.
- Example Calculation:
If you are planning a target plant density of 35 plants/m² and expect 85% establishment, and a canola seed count of 300,000 seeds/kg, the seeding rate would be approximately 1.4 kg/ha.
If you want a target plant density of 35 plants/m² and expect 85% establishment, and a canola seed count of 200,000 seeds/kg, the seeding rate would be approximately 2.1 kg/ha.
If you were to use the one seeding rate, lets say 2kg/ha you may end up with either 50/m² plant or 35 plants/m² using the seed sizes mentioned above.
Sowing rate (kg/ha) = (target plant density x 1,000,000) / (seeds/kg x expected germination)
Growers should also consider factors such as seed lot variability, seeder calibration, and environmental conditions when managing canola establishment. By understanding these variables and making data-driven decisions, growers can enhance their canola crop’s performance and overall profitability. You can make any seed size work, but you need to pay attention and adjust accordingly.
