+1 billhill Gbig2--if possible, start earlier. Aug 15, as billhill said, or even earlier if you can keep the seed bed moist at all times. Without exception! I'm in Bethlehem and going August 1, but that's going to be difficult to hold. I started plugs for the lawn (to fill in the inevitable bare spots) on June 27. They're easy to keep damp (in seed starters). First sprout was on July 3 already because of the warmth. This morning, there was a nice green fuzz.

Thanks bp that settles it for me. The seed is scheduled to arrive today or tomorrow, and I will get it down ASAP. With a completely new lawn how easy is it to "lightly rake" the spreaded grass seed withouth causing rows? Typically I would scatter the seeds by spreader, then add a very light coat of peat moss and then roll the area to pack it down. I've read a lot of recommendations to get the 1/8"-1/4" depth with a new lawn by after spreading lightly rake, but I can't imagine this wouldn't mess up the uniform spread of the seed? I need every advantage I can get because I'm just now (stupid me) reading about just how long KGB takes to germinate. I'm very scared the seed with barely sprout before we get a cold snap....

Since you are overseeding you want to use the starter at the very least. Starter is high in P, which is primarily for root growth, important for new grass. It is also pretty high in K, which is also important for seedlings. Most starters contain a fair amount of N as well, it depends on the brand but usually it's in the 16-25 range. If you use the starter at the full bag rate, you can use a reduced rate of the fall fertilizer to get more nitrogen if you want, but it's probably not necessary since you don't want your existing grass growing so fast and lush that it will out compete the new grass.

Where do you live? What kind of seed did you put down? Did you use a starter fertilizer? What is your watering program - how often and for how long? Lawn care is as easy as watering, mowing, and fertilizer. You're already overthinking it. This is the right time of year to seed a northern grass to minimize weed issues. Had you come here before seeding we would have suggested you water the bare soil daily to sprout any new weeds and then spray those out with RoundUp. Then you could seed without fear of getting weeds. But here we are. If you have broadleaf weeds in the old lawn, spot spray with Weed-B-Gone. If you have chickweed, clover, or oxalis, you'll need Weed-B-Gone Chickweed, Clover, and Oxalis killer. It's a different, stronger, product. It will not harm the old grass, but read the label for instruction around new grass. Forget about weed n feed products. They usually don't do what you expect them to do. The problem is when you need weed killer you don't need fertilizer and vice versa. If you want to fertilize now I would use an organic. You can use that at any time even on the day you fertilize with a chemical fertilizer. They do different things for the soil and plants. You can use the organic over the new and old lawn at the same time and at the same rate. Start with 10 pounds per 1,000 square feet. In 3 weeks you can reapply at the normal rate of 15-20 pounds per 1,000. But you do need to spot spray the weeds in the old lawn. Then around Thanksgiving or so you can fertilize with a high N fertilizer for the winter.