Broadcast seeding in April

Anticipating a very wet spring, some growers are wondering whether to broadcast canola seed while the ground is still frozen. That way, they at least have a chance of getting a crop if the ground stays wet into June. This might work, but beware the following risks:

Expect a poor and uneven stand. Canola can start to germinate at temperatures as low as 1°C. Seed broadcast in early April could start to germinate within a week if weather turns warm. It could germinate before the ground thaws, which will almost certainly lead to seedling death. A high seeding rate may compensate for higher than average seed and seedling mortality. Those seeds that do take root and grow will likely do so at a broad range of days and in a patchy formation, producing a highly variable stand.

Careful mixing seed and fertilizer. The ideal is to use a floater with two tanks, one for seed and another for fertilizer. If growers do not have a broadcast applicator with two tanks, blend seed and fertilizer in the tank just before application so their time together is limited to a few hours or less. Fertilizer, especially any kind of nitrogen fertilizer, can start to reduce canola seed germination rates within a couple hours of blending. Larger canola seed has more surface area and in some cases a thinner seed hull, which means less protection from fertilizer toxicity and salt effect. Consistent seeding rate is an added benefit of having two tanks. With a separate tank for canola seed, the floater is more likely to apply the same seeding rate across the whole field. With canola seed blended with larger fertilizer prills, the seed and fertilizer may not maintain a consistent ratio throughout the tank.

Crop insurance depends on establishment. Broadcast canola does not automatically quality for crop insurance. The established stand must be inspected and meet crop stand standards before it can be insured. If the crop does not grow and the ground is too wet to seed, the grower could be eligible to receive an unseeded acreage benefit. Rules for unseeded acreage benefits vary by province. In Alberta, for example, growers qualify only if 10% or more of acres in the area remain unseeded.

Farm saved seed is illegal for most varieties. Any canola seed with a herbicide tolerance (HT) system is protected under contract. Growers cannot legally use farm saved seed from these varieties and hybrids.

Published on March 9, 2011