When assessing how late is too late to seed Argentine canola, start with the average date of the first fall frost. Here are maps showing average dates for first fall frost in each province: Alberta Saskatchewan Manitoba Most fall frosts occur within two weeks either side of the average date for your area. Next, look at days to maturity for the variety, adjusting for regional differences, and work back from the frost date. For example, if the mean date for first fall frost in northeast Saskatchewan is the week of August 31 to September 6, according to the map, then an Argentine canola variety with 100 days to maturity should be seeded by May 20 to be at lower risk of fall frost damage. The Saskatchewan crop insurance deadline is June 20. Growers seeding in that May 20 to June 20 window can take these steps to reduce their risks:
1. Switch to an earlier-maturing variety. Switching from a long-season Argentine to an early-season Argentine can gain a week. Switching to a Polish variety can gain two weeks, but Polish canola has lower yield potential to start with and doesn’t offer the weed control options.
2. Seed shallow. Canola seeded half an inch deep can emergence 3 or 4 days earlier than canola seeded deeper.
Increase the seeding rate. A higher rate means a more dense stand, which means less branching and overall earlier maturity. This can gain a day or 2.
3. Pop-up phosphate fertilizer applied with the seed can gain a day or 2.
4. Reduce nitrogen rates. Nature has already taken care of this, to some extent. With the wet conditions, losses for pre-applied nitrogen will be higher than normal, which is the equivalent of cutting rates. And with heavy weed growth, those weeds have also cut into nitrogen reserves. Lower nitrogen availability means the crop will not be vegetative for as long, which means the crop will mature a day or 2 earlier.
Thanks to Murray Hartman, oilseed specialist with Alberta Agriculture and Rural Development, for help with this article.