I had a new lawn hydroseeded in early June. Now the grass is coming up, but the weeds are growing like crazy. I've got many different kinds of weeds including crabgrass. I've read that you shouldn't put down and broadleaf weed killer on a new lawn until you have cut it 3-5 times. Another problem is that the grass isn't really growing in a lot of places. It grew to about 1-2 inches then stopped, so a lot of the grass isn't even seeing the lawn mower blade when I mow to knock down the weeds. is their anything I can do this year to start killing some of these weeds?