We are closing on the house we built later this month no date yet and I'm hoping someone with more knowledge than me can help me with hydro seed. The landscape guy will hydro seed up until the first freeze. Will the grass be fine survive the winter? I have a dog and want to put a fence up as soon as we close but would also like grass but I don't want to waste the money if I will have to start over next year. Any help is appreciated. I'm in northwest Ohio.

I would do it now, because in the spring you'll be dropping crabgrass preventer, and that'll prevent your grass seed from germinating.

If the grass is the right type, and it germinates, it will survive the winter fine. There are two issues here. If you do it too late the ground temps will not be warm enough for seed germination. This isn't too big of an issue as if it doesn't germinate, it will do after the winter when the ground temps get warm enough again (as has been covered). The second issue is if the seed is the right type. Many in this area use a blend of seeds. In most of the blends is an annual rye, this grass grows very quickly and gets good coverage so you don't have issues like run-off. However, this type of grass dies off in the winter never to return. Not usually an issue as the other seeds normally have a good foot hold and take over where the rye left off. You just need to be sure to use a good quality seed mix that has been developed for the climates in your area. It has also been my experience that seeding is fine up until the frost season gets here, but that time can change from year to year. If I remember correctly, 50 degrees is about perfect for ground temp and the grass seed I used down here in SW Ohio. You may want to check with the seed supplier for what they recommend.

This is the supplier I used and I highly recommend from my experiences.

Thanks for the replies, the landscaper will be using a mixture of rye, blue, and tall fine fescue grass seed. I'll check that link out to see if that is similar to what they recommend.