Across the state, temperatures are dipping into the low 20s, which raises concern about winter wheat. To understand the potential for damage in winter wheat, it is important to stage your crop. Prior to Feekes 6, the growing point is below the soil surface and protected from freezing temperatures. (If you are unsure whether your wheat is at Feekes 6, please see this YouTube video: https://youtu.be/iukwznx4DPk?si=3EYikNsszFwDSb82). At Feekes 6, the first node appears and pushes the developing spike above the soil surface, which can be damaged by low temperatures.
The magnitude of freeze damage depends on: 1) temperature, 2) duration of exposure, and 3) wheat growth stage. A few years ago, we conducted a freeze chamber experiment to examine the effect of low temperature on winter wheat at several growth stages (Table 1). Keep in mind, actual yield reductions in the field can be quite variable depending on the weather during the remainder of the growing season. At the Feekes 6 growth stage, temperatures >20°F caused no damage. However, by the Feekes 8 growth stage, temperatures of 25°F to 28°F caused a 10 to 25% reduction in wheat yield. These temperatures were collected from the crown of the wheat plant, not the air temperature.
|
Feekes growth stage |
5% reduction |
10% reduction |
25% reduction |
50% reduction |
|
 |
Temperature (°F) |
|||
|
6 |
20.1 |
17.9 |
14.8 |
11.9 |
|
8 |
30.7 |
27.6 |
24.6 |
21.9 |
|
10.5.1 |
28.7 |
27.8 |
26.3 |
24.1 |
As much of the wheat in Ohio is at green-up (or early green-up), I don’t anticipate damage from the incoming cold temperatures. However, farmers may want to assess their wheat crop when temperatures begin to warm up again.
Table 1. Temperature (15-minute duration) at which wheat yield was reduced by 5%, 10%, 25%, and 50% at Feekes 6, 8, and 10.5.1 growth stages. (Data from Lindsey et al., 2021).
For more information, see our ‘Freeze Symptoms and Associated Yield Loss in Soft Red Winter Wheat’ FactSheet: https://ohioline.osu.edu/factsheet/anr-93