On Thu, 6 May 2010 09:10:27 -0700, "Bob F"
wrote:

Pete E. Kruzer wrote:
I'm trying that new grass seed that Scott has, guaranteed to grow. It
seemed to work for the neighbor.
How long should I wait before I have pre-emerge applied to prevent
crabgrass?

I'd probably wait until all the grass has started growing.

I'd wait until next spring. There is only a short window for applying
pre-emergent crabgrass killer... once the crabgrass seeds sprout it's
too late... read the directions for when to apply in each zone.
Crabgrass pre-emergent has nothing to do with turf grass, it only
prevents crabgrass seed from germinating. For this season all one can
do is dig up grabgrass by hand... defoliants work but then there will
be lots of large bare spots.