"Eddie G" wrote in message
. ..
Every year I put down pre-emergent's and when the barrier gets broken from
the lawn service I get crab grass. So I was thinking since there is no
way
to stop the seeds from germinating that the only way to get rid of it
permanently is to let the seeds germinate, then kill it with roundup
BEFORE
the grass matures enough to produce and drop seeds.

Does this sound like a good way to get rid of it permanently? I figure
the
challenge I have is that when it grows I don't stop it from maturing and
dropping seeds.

Crabgrass is hard to control and takes a bit of effort every year. In the
early Spring as others have noted, a pre-emergent treatment is required to
prevent the plants from sprouting. But later on, say in July, you need to
use a specific crabgrass control to kill plants before they can drop their
seeds.