On 8 Aug 2003 12:48:56 -0400, Dee wrote:

My lawn is fairly weedy. I would like to kill the weeds without harming
what grass is left (probably using a 2,4-D type spray) and then reseed in
the fall. How long do I need to wait before I reseed?

At least 60 days, 90 days is better. Spring is a much better time to
treat broadleaf weeds. I would hand pull weeds 90 days prior to
overseeding. If you have very little grass, you can use RoundUp over
the entire lawn, then reseed in two weeks. If you use the RoundUp
method it would be a good time to spread a load of topsoil and compost
just before seeding.