After a (short) second round of winter last week, there has been some concern regarding winter wheat. As a reminder, the magnitude of freeze damage depends on: 1) temperature, 2) duration of temperature, and 3) wheat growth stage. During the cold snap last week, the majority of winter wheat in Ohio was at the Feekes 6 to 8 growth stage.
The incoming cold temperatures are not likely to impact winter wheat. The magnitude of freeze damage depends on: 1) temperature, 2) duration of temperature, and 3) wheat growth stage.
Prior to the Feekes 6 growth stage, the growing point of wheat is below the soil surface, protected from freezing temperatures. Most of the wheat in Ohio is at the Feekes 4 (beginning of erect growth) or Feekes 5 (leaf sheaths strongly erect) growth stage and should be unaffected by the incoming cold temperatures, predicted to be mid- to low 20s on Wednesday and Thursday.
Overnight temperatures on April 15 and April 16, 2020 dropped into the low to mid 20s across a large portion of Ohio (Figure 1), and unofficial reports show a few locations briefly dropped into the upper teens! These temperatures were generally 12-20°F below average (1981-2010). A closer investigation at a few of the colder sites reveal temperatures remained below 32°F for 9-11 hours, below 28°F (hard freeze) for 7-9 hours, and below 22°F for 3-5 hours.
It’s important to correctly identify winter wheat growth stages to enhance management decisions, avoiding damage to the crop and unwarranted or ineffective applications. Remember, exact growth stage cannot be determined by just looking at the height of the crop or based on calendar dates.
Between planting in the fall and Feekes 4 growth stage (beginning of erect growth) in the spring, winter wheat is vulnerable to environmental stress such as freezing temperatures with limited snow cover, saturated soils, and freeze-thaw cycles that cause soil heaving. All of which may lead to substantial stand reduction.
temperature, and 3) wheat growth stage. During the cold snap last week, the majority of winter wheat in Ohio was at the Feekes 6 to 8 growth stage.
