Are The Increasing Soil Temperatures Disrupting Pre-Emergent Schedule?
Q: Are the increased soil temperatures the last few weeks disrupting the schedule for applying pre-emergent to lawns?
A: You are very observant! Crabgrass seedlings emerge when soil temperatures hit 55 degrees for a few days and the trend is higher. In past years this has happened in late February and early March. My usual recommendation is to put out pre-emergent in early March but there’s nothing wrong with applying it in mid-February. The chemicals that keep seeds from germinating are broken down by soil organisms, which are not very active in cold soil.