Canola Targeted Plant Density
The recommended plant density for canola is five to eight plants per square foot.1 Plant densities higher than eight plants per square foot do not contribute to higher yields. Plant densities lower than five plants per square foot can put you at risk for reduced yields. Knowing the target plant density, the thousand seed weight (TSW), and the emergence rate, seeding rate can be calculated with the Canola Council of Canada’s seed rate calculator available at https://www.canolacouncil.org/calculator/seeding-rate.
Determine your target plant density.
The Canola Council of Canada recommends a plant stand of five to eight plants per square foot. When determining your target plant density, consider the risks for low and high plant densities.
Risks associated with a low plant density are:
- Non-uniform plant stand- this may be affected by the seeding practices or the field variability. A low emergence rate could be the cause of low plant density. In fields that historically have patchy stands, a low seeding rate can compound the issue.
- Increased risk of yield loss due to early season frost- if your plant density is low, there is little buffer room for early season risks such as a stand-reducing frost. However, frost can kill an entire plant stand so seeding rate is not the only solution.
- Weed control- low plant densities allow more room for weeds to grow. Vigilant weed management will be important if plant densities are lower.3
- Insect pressure- Do you expect feeding damage from early season insects? Heavy insect pressure can reduce plant stand. Consider using new seed treatment options including BUTEO™ start seed treatment for increased early season flea beetle protection.
- Delayed maturity- thinner plant stands may have increased branching. This can cause delayed maturity since branches flower and mature later than the main stem. In a short growing season, maturity may be an important factor to consider.3
- Lodging- areas with fewer than two plants per square foot can have lodging where large plants are not supported by neighbouring plants.4
Risks associated with high plant densities are:
- Lodging- high plant densities (more than 14 plants per square foot) can result in increased lodging as stems are thin and pods may be concentrated at the top of the plant.4
- Disease- high plant densities can be more at risk for yield loss due to sclerotinia. A thick canopy and increased lodging can create ideal conditions for this disease.1
Use Canola Council of Canada’s target plant density calculator available at https://www.canolacouncil.org/calculator/target-plant-density to assess your risk factors.
Determine the expected emergence rate.
The emergence rate for canola can vary dramatically and has been reported as low as 23%5 and as high as 90%.6 Emergence can be affected by soil temperature, soil moisture, seeding depth, seeding speed, seed-to-soil contact, fertilizer placement, seedling disease, and seed quality. Consider using farm and field records of assessed plant densities to determine your typical emergence rate. If this not yet known, then start with the typical emergence for canola (50 to 70% of the seeding rate).5
Assess actual emergence.
It is a good idea to assess typical emergence rates to optimize your seeding rate. This is best done at the two to four leaf stage or 21 days after emergence. Count the number of plants per square foot in multiple places in a field. You can use the seeding rate calculator again to calculate actual percent emergence.
Contact your local Bayer representative for help with optimizing your seeding rate.