A cold spring is tough on crops
We are however, getting to the point when damage can occur since most fields have already reached or passed the stage we call “internode elongation”, more commonly referred to as “jointing.” After the plants reach the reproductive stage which is indicated by elongation of the top internode and formation of the embryonic head plants are more susceptible to cold injury. At internode elongation wheat can tolerate temperatures of around 25 degrees for short periods like just before dawn on cold mornings. But when it reaches the boot stage 30 degrees is pushing the envelope, especially if the wind is blowing pretty strong and the cold period follows several days of warm weather. There is a little safety factor here, but not much.
Wind is important since it quickly removes any heat being radiated from the ground that might protect wheat in calm air. So, if temperature falls below 30 and the wind is blowing hard you had better go look after a few days, or call one of us to help you since this is a tough call. Hopefully we won’t have to deal with this issue, but this year has been full of tricks so far and it is probably not finished yet.
The worst frosted wheat I have ever seen still produced about 30 percent of its potential yield on secondary heads that pollinated after the freeze. Nature has a way of surviving, but sometimes it’s not pretty and seldom if ever pays the bills.