Sorry, I should've said "ideal" 60-70 deg. Up to 80deg is considered acceptable, but when it is that hot you really have to stay on top of the watering. But maybe out there it is really humid. Out here, 80deg means watering very frequently just to keep the ground wet. Once the seeds have gotten wet, if they let them dry out then they are toast. I also shouldn't have said late fall. I was thinking late Sept, which would be when temps are around 70F. In my experience, once the average daytime temp drops below 50, growth pretty much stops. That would be right around late Oct, and if they are like us, that is when everyone blows out their sprinklers for winter. Given the colder temps, full germination will be right around mid Oct, and by late Oct the new sprouts will be about 1" long. This means watering by hand for us, because even though it's cold, the new growth still needs to drink. IMO, that is really annoying, but I don't like to risk an early freeze damaging my sprinkler system. I don't have to worry about any of that when seeding in Apr. But to your other point, you can still seed in Apr even if the temps aren't quite high enough. They'll start to germinate as soon as the soil gets above 50-ish. And if the lot isn't shaded, soil temps reach 50 before air temp does. Anyway, I accept that Sept is the recommended "best" time to seed. My point is that early/mid spring is acceptable enough to go ahead and do it. If a person follows those steps, they will get perfectly acceptable results from a spring planting. I don't think there's any real compelling reason to wait until fall to overseed. Does it really matter if 20% fewer seeds germinate? Seed is really cheap and if a couple spots don't take, get them again in the fall.

Hard to know where to start. You did good by seeding in Sept. Don't know what went wrong with the sprinkler but maybe you have the wrong one. I recommend an oscillator type for even coverage over a pretty big area. The newer turbine oscillators are better than the old mechanical ones. If you don't control of your watering then you are doomed to having a weed lawn. You absolutely cannot trust Mother Nature to help you water new seed. It MUST be watered 3x per day, for 10 minutes each, at breakfast, lunch, and dinner. Nature will never get that right. If you are going to spend the money on good seed, you should commit to the watering needed to make it sprout. KBG takes 3 weeks to sprout, to it is a commitment. Rather than spraying over and over for weeds, I would suggest you wait until fall to seed again. Yes you made a mistake that got in the way of your seeding. Next year do it right and you won't need this forum!!!

Thanks for the info. You are watering far too much. When watering new seed you should water 3x per day, for several weeks, until you have 80% germination. You do not need to water inches for this. You only need to water enough to keep the seed moist. That might be 3 minutes up to 10 minutes. Once the grass is established, then back waaay off on the frequency and increase the time. This time of year a mature lawn in your area should be watered one inch, all at one time, once very 3 weeks. If you want to correct this, do not do it cold turkey. Write back for more help on that. Bluegrass easily blends in with fescues for summer time color and appearance. Bluegrass will go dormant (turn brown) in the winter while the fescues normally remain green, so that is one difference. Otherwise, the blend works perfectly. The new stuff will eventually die out due to rare insects or rare disease. Bluegrass will also suffer under those pressures, but it will return. The fescue and/or rye you might have will die and remain dead. Until that time, you are stuck with what you have.

You don't want to force feed a lawn at this time...that just causes increased growth and if an early frost hits, the lawn can be damaged. The starter fertilizer would have been added at seeding time and no longer is it required. Wait for any pushing to be done in the spring. As far as protecting against winter, just maintain the lawn in watering and mowing a height that will not invite damge from frost. The first cut should be a high one....3" to 3 1/2" is fine. Going lower at this time with new grass invites damage if an early frost occurs. Keep the height at this level and let the grass mature gradually. Lower mowing can be accomplished in the spring when, at that time, a further layering of compost/topsoil/triple mix..can be given the lawn prior to the first mowing. Let the grass grow up through this topping. This then feeds the soil--increases the nutrtion the new grass will appreciate. Then you can drop the height to 2 1/2" - 3" and maintained at that height.