Last week we saw 3 consecutive nights in the 20s, with the lowest reaching 22 in some areas. Now that a week has passed, we can see the signs of damage on some of our jointing wheat.
You wouldn’t know it just from looking at this field from the truck, but when we split the stems and look inside at the developing heads, the damage is apparent. What we should see in a healthy head is a nice white color and a turgid structure. Typically we can distinguish each individual floret.
Healthy grain head. White in color and turgid structure.
The grain head below was damaged by the cold. You can see that it has lost its turgidity and looks kind of like the tip of a thin wet paint brush. It’s hard to see in the photo, but the color has turned to a pale tan. Color isn’t always the best indicator because differences can be so subtle that they are hard to see.
The image at the top of this article shows a good head on the left and a damaged head on the right.
These heads that are damaged won’t continue to develop, though the plants may remain green. If you are seeing a significant amount of damage in your fields, it may be wise to consult your crop insurance agent before adding any more inputs (i.e. fungicides at flag leaf). Here is a good publication describing exactly what happens to the plant when injured by cold weather. If you would like help identifying damage in your fields, please contact your local Extension Agent.
Will Neel, a farmer in Newberry, South Carolina, told us today in a report about freeze damage that “oats and barley were devastated in my area, with wheat about as bad.”
In one stretch, the temperature fell to 24 degrees at 3 a.m. and by 8 a.m.it had dropped to a low of 18, then remained below 25 until 10 a.m.
“The rule of thumb here is that 5 hours at 25 or below will freeze the stem and the head will die,” notes Neel of Neel Brothers Farm. “In 48 hours we could see a white girdle around the stem, making it obvious that the tissue had been frozen.”
The family’s operation is in the midland to lower Piedmont, he added.