If you're topdressing with 1/4 inch, I'd seed first. The topdressing will give a light covering and help the seed germinate.

And here I come to convince you do avoid top dressing.

I'm convinced any soil can be reclaimed by natural methods. All you need to make excellent soil is a little compost (1/4 inch), organic fertilizer, water, and time. Use the compost the way you were going to use the top dressing and you'll be ahead.

LOL, I was just reading one of your posts yesterday about how you don't recommend soil for topdressing and wondered if you would weigh in. (: I love the idea of reclaiming my hard clay eventually (when I aerated, some of the plugs that came out were hard little bullets that still haven't broken down!).

However, in the middle of our front yard, we have two access panels down to the telephone/hydro/cable lines that are buried in newer subdivisions around here. Last fall, I bent my lawnmower blade hitting the cement corner of one, and this year, the soil around both panels has settled quite a bit more. I was thinking that I'd use the soil/compost mix to fill in some of these areas, rather than straight compost, which will decompose eventually.

However, I also don't want to raise the level of my yard so that I scalp the grass when I mow on the edge by the driveway.

So, should I just use the soil mix to raise the lower areas, and compost on the rest of the yard? Given the quality of the existing soil at this point, I also wanted to ensure my overseeding was successful.

Thanks!

Top dressing does not ensure success of seeding. When Mother Nature reseeds grass, She does it with cattle. They knock the seeds off the grass and trample it. They don't till or top dress. Any "top dressing" the cattle may leave behind gets processed by dung beetles and other critters that specialize in the scattering of dung. Thus the key to successful seeding is to trample the seed down. Most professionals use a water fillable roller. After you seed, you can roll the seed down. Or for a small area, you could walk on it. Heck, have a party on it. Until the grass sprouts, you are very safe to walk on it.

Yes, if you have low spots, you can bring them up to grade. Mowing at the edge of concrete can be tricky.