Last year UMd recommended 2 applications of crabgrass pre-emergent (March and...
Last year UMd recommended 2 applications of crabgrass pre-emergent (March and early May). This spring is much cooler. If I did a pre-emergent application on March 23, is a second application recommended this year? And when should it be done? Last year's program was effective. Thank you.
Yes, the cool spring has also resulted in cooler soil temperatures which has impacted the germination schedule of crabgrass, so a second application of pre-emergent herbicide is recommended at this time. A pre-emergent chemical application is essentially the laying of a chemical barrier which is designed to kill a seed that is attempting to push a root down through it or a shoot up through it. This barrier will not last all summer, and there are at least two flushes of crabgrass seed germination, so it is important to make that second application.