Most of our wheat in southern Ohio was at or beyond Feekes growth stage (GS) six, or jointing, prior to the weekends cold snap. This GS is indicative of the growing point or “wheat head” emerges above the soil surface and begins to become more sensitive to cold temperatures as the wheat progresses from this point out. Temperatures were forecasted to go down to 15 degrees on Saturday early morning and many wheat growers were concerned. The good news is that I don’t think it got that cold. Here is a good commentary from Dr. Shaun Casteel, wheat specialist at Purdue University, on Friday.
The cold snap comes just as much of the state’s winter wheat crop has “greened up” and is starting to joint, said Shaun Casteel, Purdue Extension wheat specialist.
“A lot of areas have been greening up,” Casteel said. “Plants from tillering stage to Feekes 5 can withstand quite cold temperatures in the 12-15 degree range without substantial damage to yield.”
More mature plants, however, could be at greater risk.
“At the jointing stage, Feekes 6-7, the temperatures that can cause damage are at the 24-degree mark and below,” Casteel said. “If you’re in that range for more than a couple of hours, the concern is beyond leaf tip burn.”
Providing adequate nutrients can help wheat plants cope with the cold, Casteel said.
“Wheat that has been top-dressed with nitrogen and taken it up fare better than those plants with nitrogen deficits,” he said. “Adequate nitrogen in the plant is almost like an antifreeze agent.”
Casteel said freeze damage might not be apparent for 7-10 days.
“You have to let the plants grow out a little bit before determining what damage has been done,” Casteel said. “If you are looking at yellow and brown leaves, that is mostly cosmetic and won’t cause significant yield damage at the current growth stages. Under more severe conditions, the growing points die and the lower stems split or bend. That could lead to moderate or severe yield loss.”cold snap, justin rivers, milford center, novus ag, ohio, wheat