We have had three mornings with frost on April 10, 11, and 12. I took a walk on campus on the afternoon of the 12th to see what the impact of the frost had been on the crabgrass that I observed on April 2 (see earlier post). Crabgrass is very susceptible to cold damage, particularly in the seedling stage. I expected the crabgrass to be dead, but to my surprise, it appears to be doing fine. The crabgrass is in a somewhat protected area around the horticulture building, but it is an area that did have some frost.
I am still not seeing much germination of crabgrass in more exposed areas on campus and we have not seen any emergence at the horticulture research station as of April 12. It did get down to 20 F at the research station on the morning of the 11th. If any crabgrass was beginning to peak through, I would expect it to be dead. I'll continue to monitor the early germinating crabgrass over the next few weeks and let you know what is happening.
The trial in which we are applying Baricade and Dimension on April 1, 15 and May 1 to separate plots is continuing. As soon as I have some results from that work, I will put up a post.
Figures 1 and 2. Crabgrass by the horticulture building on the afternoon of April 12 after three mornings with frost.