Hi, Most of my lawn is covered with crab grass. I also have a lot of bare areas where there is shade. I had one yard company tell me that because I have so much crab grass that he thinks I should spray those areas and then aerate in the spring and put in a crab grass preventer then and wait to over seed until the following fall. He said if I aerate now and seed it won’t get through because of how thick the crab grass is. He did say to bring in dirt and seed the bare areas this fall. He said to be sure and not spray those areas. Do you think this is a good plan? I am thinking about selling my house and really want to get these bare areas taken care of. I know we will have to find good shady grass seed. Thanks, Nancy
Benton County Minnesota
I think the advice you received was mostly accurate. Crabgrass is an annual, so applying herbicides in the late summer or fall won't do anything that the first frost can't accomplish. Pre-emergence herbicides should be applied in mid April to mid May before the crabgrass comes out of the ground. Post-emergence herbicides should be applied in mid May to early June to small, visible crabgrass.
Herbicides used for crabgrass should be safe for most lawn grasses (be sure to check the label). For shady locations, look for seed mixtures specifying shade tolerance. These will contain fescues along with some common and shade-tolerant Kentucky bluegrasses.For more specific recommendations for grass seed mixes go to this link: https://extension.umn.edu/lawn-care/renovating-lawn-quality-and-sustainability#seed