Where do you live?
When was the tttf seeded? If you live south of Canada and it was seeded between March and NOW, then you should expect to see crabgrass. If it was seeded sometime since late April you would be pretty lucky to have any grass left. Between the summer heat and the extreme competition from crabgrass, spring seeded tttf doesn't have much chance.

Fall is the time to plant tttf seed. Seeding now gives you the rest of fall to evaluate and see if you need more seed to make a dense lawn. Then by the time next May comes around, the tttf will have developed strong, heat resistant roots. If you want that for next year, start now by tearing out the crabgrass. You can spray the entire yard with RoundUp (twice), and start over. Or you could work around any living grass you have by spot spraying the crabgrass.

Thanks dchall. I rounded it all up and just seeded 2 and a half weeks ago. I'm in nj. I wasn't expecting so many weeds. I think it may be because when I slit seeded I used the suggested setting on the front lawn and not enough seed was coming out. The back yard I opened the hopper all the way up and that looks better (but it also has some clovers and other random nasties). So what do I do about this crab grass what not. Is my turf screwed now?

You're probably not in too bad a shape. It just looks bad because the crabgrass has not died off yet for this year. Crabgrass is an annual plant that must come back from seed. At the first frost it will all die leaving room for your new grass to get going. But who knows when that will be? You just got too early a start on fall. If you used Kentucky bluegrass in the seed, then you can be okay for 2015 with a few tips. If you have only fescue or fescue mixed with rye, then you might want to "dormant seed" again in mid winter. Dormant seeding is when you apply the seed way too early for it to sprout. Then, when Mother Nature gives you a false start to spring with some warmish rains, that seed will germinate without you doing anything. Generally (hopefully) that will happen before the days are long enough for crabgrass to sprout. Kentucky bluegrass spreads to fill in bare spots. Fescue and rye do not.

The best prevention for crabgrass is to have a dense lawn that is properly cared for. Different grasses become dense in different ways. KBG will "densify" itself as will St Augustine and bermuda if you care for them properly. With fescue and rye you need to add more seed to get a dense lawn. Best time for that is now. It seems to me the others have talked about a weed killer that will kill crabgrass and leave the other grass alone. You might search this forum for those discussions.

Once you have a dense lawn, then proper watering is absolutely critical to preventing weeds. Seeds of all kinds like to have a continuously moist bed to germinate in. If you provide that by watering every day or even every 3 days, you're going to get weeds to sprout. If you have your grass trained to not get water except once a month in the early spring, then unless Mother Nature gives it more often, there will not be many weeds. As the temperatures warm into summer, you will have to water more frequently but never water more often than once a week (except if you live in Las Vegas). Just getting your watering right will eliminate most of the weeds.

Thanks for your time dchall. I can't wait till these weeds are gone. It looks bad. I'm using a tttf mix with 5% kbg. I guess I'll just have to wait it out and apply herbicides in the spring if they come back. Maybe I'll try to overseed more where the heavy weed spots are now too.