The begining of this year, I tried this experiment. Dethatched, raked, seeded, watered, watered, watered....

It turns out the temperatures were so low that there was no germination after 6 weeks. The birds also ate a lot. In the end I got some grass but then since I did not use any weed killer due to new seed I got tons of weeds and then crab grass. So, now the law is pretty green but it's 30% weeds and grass.



I will let it go this year and then next year hire someone to seed with a slit seeder.

BTW, does anyone know if crab grass survives the winter? How do I get rid of it?

 

Crabgrass is an annual. It will turn an ugly brown after the first frost, and it is dead. However, it left behind a wealth of seeds waiting to germinate next spring.

The standard treatment is a germination preventer put down in the spring. One rule of thumb is that crabgrass germinates about the same time the forsythia (shrub with yellow flowers) blooms. After that, you can't use the common germination perventer, but there is another chemical you can use.

 

Bill overseeding now will still be relatively cheap.
you might get some germination you might not but Crabgrass doesn't do well against an established lawn especially if you put down crabgrass preventer in the spring.
Putting crabgrass preventer gives the new lawn from this season a leg up in growing in.
As redy2ks2k said, hte germination preventer stops it but it will also stop any seed you put down in the spring as well.