I’ve gotten several calls over the last day or so about possible freeze damage for Saturday morning. The National Weather Service has issued a frost advisory for much of central and northeast Arkansas for the early morning hours of Saturday morning, with most forecasts calling for temperatures dropping to the mid 30’s, but above freezing. With temperatures above freezing we don’t anticipate any problems, but as the wind drops Saturday morning, there will likely be variation in temperatures from one point to another based on elevation, so there is a potential some areas could get to freezing or below. Freeze damage potential depends on several factors including, how cold it gets and for how long and wheat growth stage. For wheat that is in the boot stage, 28 degrees for 2 hours is enough to cause significant damage. For wheat that is heading or flowering the critical temperature is 30 degrees for 2 hours. The picture below is representative of many of the excellent fields in this area, with most in the boot stage (some earlier or later based on variety and planting date).
The type of injury that we would see if we get below freezing would be partial or complete sterility of the heads and or stem/node damage, again depending on how cold and for how long. This type of damage will take several days before it can be properly assessed.
For more detailed information on wheat freeze damage, Kansas State University has an excellent publication at the following link: http://www.ksre.ksu.edu/bookstore/pubs/c646.pdf
Hopefully we can miss a freeze. Overall wheat condition is somewhat mixed. Fields that were planted on well drained ground and have been managed properly appear to have excellent yield potential. Wheat that was planted in fields with less than ideal drainage has suffered from the wet weather we have experienced this spring.
I would say that wheat growth stage right now is a good 3 weeks later than it was in 2012. In the April 15th Arkansas Agriculture Statistics Service crop report wheat was rated 6% headed. This compares to 90% in 2012 and 32% for the 5-year average. The cool weather this spring has really slowed growth. The full Arkansas crop report for April 15th can be found at the link below: