crab grass

[Fanatical Meat]

Can I apply pre-emergent crab grass preventer then plant new seed in a top layer of new untreated soil?

 

[boomerang]

Can I apply pre-emergent crab grass preventer then plant new seed in a top layer of new untreated soil?

No, it will not allow the new seed to germinate. That's how it prevents the crab grass, it won't allow it to germinate. There is a waiting period that is measured in weeks but I can't recall the time period right now.

 

[edro]

Definitely not, but the good news is that there are decent crabgrass killers available now.
Buy some concentrate, mix in a sprayer and walk around spot treating the crabgrass.
It worked pretty well for me last year.
http://www.homedepot.com/p/Ortho-We...grass-Control-Concentrate-990601015/203686902

As with all homeowner grade herbicides, results vary drastically based on location, dosage, weather, season, user, etc.
I can tell you this stuff worked well on my crabgrass and various other weeds. I would up the ratio some though.