Hi Richard,

This is a very common weed:  Crabgrass

This UNH Extension article addresses how to remove and minimize this in your yard including herbicides that can be used pre-emergent in the spring and post-emergent in the summer.  https://extension.unh.edu/blog/2019/09/how-can-i-get-rid-crabgrass-my-lawn

One recommendation that you may want to consider is having a soil test done to make sure soil nutrients and pH are proper.  This is a service offered by the UNH Cooperative Extension for $20 per sample.  The form to fill out and directions are here:  https://scholars.unh.edu/cgi/viewcontent.cgi?article=2783&context=extension&preview_mode=1&z=<personal data hidden>