What month was seed planted? Grass needs time to root deep enough to come back following dormancy.

What kind of grass did you plant? Some grass begin growth from roots in Spring and others must go to seed each Fall so that seed sprout in Spring.

The confusing reason as simple as I can explain it.

Microbes living in the ground are responsible for decomposing dead organic matter and need a diet with a ratio of 25-30 units of Carbon and 1 unit of Nitrogen. This is the optimum ratio microbes live on, and referred to as a C:N ratio of 25 to 1.

The wood chips left behind from the stump grinding is a massive pile of microbe food but the wood has a C:N ratio of about 700 to 1 and very low in the amount of nitrogen available to feed the microbes. So the microbes turn to any available nitrogen in the nearby soil stripping it of all nitrogen.

Your grass died from a nitrogen deficiency, and it will continue to struggle growing over the wood chips for many years until the wood chips have been consumed by the microbes. To speed up the decomposition of the wood chips and maintain grass above the spot the microbes below must be fed additional nitrogen. Here is an example to get rid of wood chips in 4 years from this site. Click here.

For each 10-by-10 area:

• Year One: Add one pound of ammonium sulfate for each one inch layer of wood chips.
• Year Two: Add one half pound of ammonium sulfate for each one inch layer of wood chips.
• Year Three: Add one quarter pound of ammonium sulfate for each one inch layer of wood chips.
• Year Four: Add one eighth pound of ammonium sulfate for each one inch layer of wood chips.

In your case I'd suggest deep watering in a couple of cups of Urea or ammonium sulfate over the spot 2 or 3 times this year to speed up the decomposition process.

It's important to know where you live and what kind of grass seed you used. For example did you use a northern mix (fescue, Kentucky bluegrass, and rye) or something else? As for where you live, just the name of the nearest big city is fine unless you live in the LA or San Diego areas. Those areas have all the USDA zones in them, and some grasses do not do well in some locations. So if you live in Pomona, don't say LA - different climates.

If you buried the wood chips from the tree in the area, the fastest way to recover is to dig them ALL out and refill with fresh soil. Otherwise it is as kevin9408 said. The soil is corrupted by the buried wood. Once you have the soil back down, you can add compost and organic fertilizer TO THE TOP of the soil. Don't mix it in or you will be back to buried wood chips again. When you refill the hole there should be a mound even after you walk on it to compact it. The mound will eventually settle back down to level. If you level it now then when the soil restructures itself (over the next 3 years) it will result in a low spot.

Let us know where you live and what seed you used, and we can help more.