Growers often wonder if they should treat their seed in the fall. There are a couple big reasons for doing so — it saves time in the spring, and gives seed treatment more than enough time to dry. You also don’t have to wait in line at a treatment facility in the spring, as your seed is ready to go.
Seems like a no-brainer to treat in the fall, but it’s not that simple. Three factors to consider are:
Seed Quality. If you treat bad seed in the fall, it will still be bad seed in the spring. Ensure your seed comes from a reliable provider in the first place, otherwise you’re wasting time treating it, regardless of when you do so. Whether growers decide to treat in the fall or spring, they should get a germ and fungal scan before treatment. If either is questionable, then better seed should be obtained. Protecting poorer quality seed means that you should expect poor results even if you treat it.
Storage conditions and storage temperatures. There’s no point treating in the fall if you’re treating seed that loses germination (and/or vigour) over the winter due to poor storage conditions. A big concern is temperature gradients, which lead to a moisture gradient in the bin. Zones of higher moisture are at higher risk — not only of spoilage occurring, but also that treatments on the seed could degrade. Storing your seed in dry and cool/cold conditions will provide the best results. If you treat in the fall but do not use that seed until the following spring, you could be looking at as many as 18 months from treatment to usage. Depending on the storage conditions (temperature fluctuations, changes in humidity and moisture levels), there could be loss of either fungicide or insecticide. However, if proper storage conditions are used, the efficacy of the seed treatment will not be affected.
Crop Rotation. Some growers have a well-planned crop rotation. In this case, fall/winter treating works best. Some growers plan their crop rotation based on commodity prices going into planting, and fall treating is more risky for this group. It depends on the individual’s specific situation.
There’s no easy answer to the question of whether to treat in the fall or spring. Taking the above three factors into consideration will be your best guide to deciding when to treat seed.