Now is a good time to talk about your intentions for seeding your lawn later on. If you're using a step fertilizer program, or if you have a crabgrass problem that you want to remedy, pay attention.
Crabgrass preventers work by killing the seedlings as they emerge. Those preventers (both organic and conventional) don't know the difference between a crabgrass seedling and a bluegrass seedling. They'll kill both.
If you want to seed your lawn, you won't be able to start seed until after the pre-emergent wears off. That's 14 weeks if you've used Halts or the Scotts programs and 6 weeks if you've used Concern so plan accordingly. Of course, you could always re-sod any areas instead and have no problems.
Scotts does offers a special step 1 as a part of their 4-step program that is designed for those seeding their lawns. It's safe to put down with new grass seed.
If you do intend to seed your lawn, you should also consider putting down a straight fertilizer (one without crabgrass preventer) and spot-treating any crabgrass that may arise. A combination of our MaxLawn fertilizer and Fertilome Weed-Out with Crabgrass Killer will do a fantastic job at maintaining a healthy lawn and keeping crabgrass out.