After a mild winter in middle TN, it will soon be time for crabgrass pre-emergent. Pre-emergents have to be applied prior to seed germination to be effective. They are activated by moisture, so rain or snow after this application is beneficial, not detrimental. Soil temps are about 4 degrees warmer right now than this time last year. Crabgrass seed germination is occurs when soil tempatures at 1 inch stay at 50 degrees or above for three consectutive days. Current soil tempatures at 1 inch depth in middle TN about 40 degrees. So its time for us to get busy!