Can I use a pre-emergent if I seeded this spring?

No, if you want to seed/overseed your lawn in the spring, you cannot use pre-emergents like Prodiamine because they will kill that new grass seed as soon as it grows.

Check out this video by Allyn Hane, aka The Lawn Care Nut, for more information on this topic and also to find out just why we do not recommend seeding in the spring: 

https://www.youtube.com/watch?v=QWKzliBwx-4

Keywords: seeding, spring, seed, pre-emergent, Prodiamine, Dithiopyr, pre-emergent, preemergent