Question
I had my lawn replaced last fall, but it seems to be thin in many areas. I would like to overseed it in the spring, but am not sure when I should do it. I am also not sure how to prevent crabgrass in the spring if I am going to seed it.

Answer
If you seed in the Spring, you'll get crabgrass. It's really that simple.  There are some products that claim to provide control over crabgrass while allowing seed growth, but they really only work under perfectly controlled laboratory settings.

I would recommend seeding only those patches that are really thin and bare, then fertilizing the rest with a heavy shot of fertilizer blended with a crabgrass preventer. The fertilizer will get it to thicken up significantly.

Good luck!

Sincerely,
C.J. Brown