You can often tell the condition of a crop the day after a frost. It may have survived without any damage, in which case you may not have to worry. Or, if most of the plants are black and bent over, it may be clear that serious losses have occurred. But does that mean the field should be reseeded? The answer to that question is rarely so clear the day after a frost — which is why waiting 3-4 days can help.
With fields too wet to seed, growers in Manitoba and parts of Saskatchewan may be tempted to leave volunteer canola and harvest it as a crop. There are many reasons to avoid this, and very poor yield potential is just one of them.
After broadcast seeding, including seeding by plane or helicopter, fields must be harrowed to loosen the soil surface and provide seed to soil contact. Canola seed is very light and does not embed into the soil, even if dropped from an airplane at high speed.
Frost hit many areas of the Prairies again on the weekend. Some areas in central Alberta reported -8 C. This followed a frosts on a couple nights last week. Wait 3-4 days to see if the crop recovered before making a reseeding decision, and wait to make sure weeds are actively growing before spraying.
It can take a few days for young canola plants to recover after a frost. Even if damage looks severe, give the crop a few days to see if it will recover before considering whether to reseed. Weeds also need to start growing again after a frost before a spray will provide strong efficacy.
Growers wondering when is too late to seed canola should consider these 4 factors: maturity of the variety, average date of first fall frost, crop insurance deadlines, and profit potential of option crops.
If growers have to seed by plane because the field is too wet for a broadcast floater, that means it’s probably also too wet for weed control, fertilizing and harrowing — each important to a profitable broadcast canola crop.
Seeding deep to chase moisture is rarely a good idea early in the season. That situation changes with the warm soils of mid to late May. Seeding 1.5” to 2” deep to hit moisture will hasten germination and crop establishment in fields where the top 1” is too dry to allow germination and emergence.
Scouting now will identify early insect and weed pressure, identify establishment problems that may have been the result of drill settings or drill malfunction, and give you a benchmark to work from in the event of frost or wind losses.
The economic return will be higher than if the grower seeded over these large weeds and then took a chance on getting them sprayed before crop emergence.