sorry to have deleted your response my mistake
You responded to me but accidentally deleted your response to my questions regarding the approximate times to put down a preemrgent on the lawn. I think it had something to do with when forsythia blooms but not sure. Sorry for troubling you again.
We believe this is the answer we sent to you.
Most likely you are referring to a preemergent to control crabgrass. For season-long crabgrass control, consider applying your preemergent twice (but make sure the product you choose does not contain fertilizer).
Apply first in early spring when the forsythia blooms begin to fall from the shrub. Crabgrass germinates at 54°F, and this is coincident with the forsythia blossom drop. A second application of the product is necessary about 6 weeks later, usually in May.
To help prevent crabgrass, reseed and thicken up your lawn in the fall, mow at 3 inches, and fertilize in the fall.
See the following publication TT-43 Herbicides for Crabgrass http://www.mdturfcouncil.org/admin/uploadfiles/tt-43e-crab.doc