You've probably seen the definition of insanity: doing the same thing over and over and expecting different results.

If your landscaper is at a loss as to whether the soil chemistry is good or bad and cannot figure out how to fix it, then you need to fire him. He's not a landscaper, he's a lawn mower. A landscaper would have had the soil tested at the beginning. And a landscaper would not have continued to bring in more and more top soil. At this point, before you do anything, you need to take a hard look at your drainage. Is your lawn crowned significantly (higher) in the middle and sloping off to the sides? Is the whole area on a slope (which could be mitigating circumstances)? When it rains does any water collect and puddle on concrete near the house? If so you should have the soil removed which is blocking your drainage.

<img src="http://bloy.net/images/2013/07-21-large.jpg">;

Water should drain off of concrete into the soil, not the other way around. If you're getting this then soil needs to be removed.

Once you've established a final soil level (whether you remove soil or not), get the soil tested at Logan Labs in Ohio. Then post your results here on this forum. Look down the forum topics list for other Logan Labs soil tests to see what you get by posting the results. The basic test is $25 and is all you need.

When they ground the roots, did they remove the ground up chips or did they bury them in your yard or the hole where the stump was. Sawdust or wood chips should never be buried or rototilled into the soil. There's a long biological explanation for why, but essentially the decomposing wood underground robs nitrogen from the soil leaving none for the grass or other plants. It can take 10 years or more before the soil can recover from buried wood. If your wood chips were scattered on top of the lawn, that should be fine, but just not buried. If they were buried or raked in, that might be a good reason to remove soil from the surface.

Is there still much shade in this area?

What was your watering schedule for when the new seed was down? How often and for how long? And what is your watering schedule for the rest of the lawn?

Where do you live?

What kind of grass were you seeding?

Thank you! Let's see - it's a flat surface (most of the topsoil ended up being used to level it out), and water does drain from the sidewalk onto the tree lawn. Full sun almost all day. The chips were removed as much as possible, they weren't buried or tilled in but I'm sure a few were still left on the surface. We watered, as told, twice a day for about 10-15 minutes each time. I am not sure what seed was used, we live in NE Ohio.

We do live opposite a cul-de-sac, which is the only part of the street that gets salted in winter. Could that be a culprit? It was also suggested that the lawn service may have used a pre-emergent, but that would have been 6 weeks ago and the latest topsoiling would have covered that.

I'm just stumped by this. We've had a lot of reseeding done over the years because of one thing or another (new patio, taking out a garden, etc) but have never had a problem with the grass refusing to sprout.

Just an FYI in regards to a remedy for one of your concerns. Applying gypsum can counteract the affects of salt contamination without creating additional adverse affects.

...Except for increasing calcium in the soil, which may or may not require it, and increasing sulfur in the soil, which can get in the way of seed germination in the future.

As mistakes go, gypsum would usually be reasonably minor, but can still take several years to correct itself. And the mistake, once made, can't be easily corrected by anything but time. We can't abolish calcium except with an acid, which we don't usually apply directly. And we can't get rid of sulfur except by applying more calcium.

In that case, if you have salt contamination, learn to live with a lack of turf or put in gravel.