I wouldn't till. I think you should just put in the sprinklers and have him seed.

If you want to stick with a water wise lawn and you only object to the fescue, you could go with streambank and/or western wheatgrass. They need less water than tall fescue (but probably a bit more than sheep fescue). That way you could skip the sprinkler system.

If you're sticking with Kentucky Bluegrass (KBG), you want to get the seed in as soon as possible. It would have been better if you had it in already. Since it's being hydroseeded, it's imperative that you keep it moist until it sprouts. Since it's relatively cool and damp, you may be able to get by watering twice a day, but you may need to water three times a day for a while (adjust for any rain, of course). You'll just barely see it germinate before it starts heating up and summer is tough on KBG.

I shoot for once or at most twice a week watering even in the heat of the summer (actually, now that the wheatgrasses are taking over, I'm hoping for once or twice a month starting in late June or early July). With grass that young, you'll probably need to water almost daily. Contrary to popular belief, once the grass gets established, it's best not to water every day. You can keep a KBG lawn nice and green watering no more than once a week most of the season and no more than twice a week in the hottest part of the summer.

If you're using culinary water, it's going to be expensive to get it through the summer this year, but if you water deeply and infrequently and mulch mow high, you can use a lot less than most people in the state do.

Thank you for the advise. I had read its probably better not to till but why? If not should I aerate the ground before I seed? Anything else to prepare the ground? I'm assuming I would mow the dead grass as low as possible? Will the seed be able to root well enough, or deep enough, through the dead grass root bed?

I think I still plan on Bluegrass because I have 3 young kids and the I want a soft play area for them. I also know I have walked through Bluegrass barefooted with no ill effects.

Tilling has several effects on the soil. From a physical viewpoint, it is almost inevitable that you will develop low spots and high spots, which will drive you crazy. From a soil biology viewpoint, you wreak havoc on the beneficial soil microbes that make your lawn work. From a weed control viewpoint, you move seeds that are laying on the surface into the soil, and expose long-buried seeds (believe it or not, up to 30 years on some seeds) to be exposed to light, where they germinate and make uber-ugliness. Use RoundUp to kill the grass and scalp it as low as possible. That is your best chance for overall success. I did tilling on a backyard renovation 7 years ago, and it took 5 full years to get back to "normal". I did a no-till renovation late last summer on the front yard, and the soil tests and weed levels so far this year are very encouraging.

Aerating will expose more soil and help with seed to soil contact. You could do something like power rake or dethatch to get a similar effect, but core aeration has other benefits and you wouldn't need to rake up the thatch with core aeration.

If you core aerate, make several passes. If you hire it done, consider paying a little extra and asking if they'd make an extra pass or two. The more cores pulled, the more open soil there is.

Power rake, I've got three, and I love them dearly. It will prep the bed for seed without disturbing the soil too much. It will also knock down high spots and fill in low spots.

I agree there are lots of good points here. I would probably power rake to no more than 1/8 inch deep and start a compost pile with the grass coming out.

Fall is the best time to do this but you are already committed. You should expect to see some crabgrass this season. Just enjoy it and it will die by itself in the fall. Then the KBG will fill in for you.