My grass didnt green like my neighbors did in late feb-early march and I started getting a lot of dollar weed. At the same time, 6 Weeks ago, I used "Scotts weed and feed bonus-s" to get rid of some of the weeds which it did, it also greened my lawn up fairly well. I adjusted my 4 zone sprinkler system to 10 minutes per zone 2 days a week for a week to destroy the dollar weed. I then moved them to 15 minutes twice a week.

This is the 6 week mark and the grass is filling in very nicely and Im getting a nice turf in the front and back. Granted its not completely green but its getting there. For the past 4-5 days Ive had my eye on a spot in my back lawn which was very lush and green for several weeks now start to look dehydrated. We've been a bit dry, but I still water 15 minutes in the back and the area seems to be getting enough water.

The tops are darker green, blades are folded and the grass almost seems to lay down. In the image below, you can see the spot. I outlined it in purple.

http://g.imagehost.org/0885/overview.jpg

This is a closeup of the area

http://g.imagehost.org/0401/closeup2.jpg

This is another shot of the area

http://g.imagehost.org/0837/near_house.jpg

This is a shot of my lawn where its growing great and how that dying area used to look. This progression took 4-5 days.

http://g.imagehost.org/0722/healthy.jpg

anyway, like I said im new with this. Ive owned a house before, but it was in Alabama where we had actual soil. Here we have a lot of sand and rock. The drainage in this new house is bad, but I can tell its improving probably due to the root system establishing. Any feedback would be much appreciated

Thanks!

Most likely problem was/is insufficient water. The Keetch-Byram Drought index (KDI) is in the 600-650 range and it is very, very dry.

Short watering events cause shallow roots - making the problem even worse. You need to get at least 1/2 inch and preferably 3/4 inch water down when you irrigate.

Put out 2-3 pans in a zone, water until they have at least 1/2" of water, 3/4" would be better. Then set your timer for that length of time. Also make sure your spinkler head is working in that area (edited to note this based upon a later post).

First you said it was a new house, and second you said it was "very" dry.

Look at the first picture you showed us. It looks almost to perfect of a shape. Normally disease or (especially) insect damage is not that perfect.

I would take a wild guess it might just be a piece of plywood from construction. If you look at the spot of interest it forms almost a perfect "L". This sadly is not uncommon, along with rocks, and other building materials.

If this is the case just take a long metal rod of some sort and just poke it down 6-12" and see if you hit something hard. Hopefully you will and you can just simply remove it, and water like normal.

Hope it helps.