What is the "NPK" of that miracle grow plant food? You might be putting down too little nitrogen and too much of the P and K. I don't think that that fertilizer is designed for lawns.

Also, do you know how much water you are putting down during each watering? The rule of thumb is one inch per week, and figuring out how much water your system is putting down per watering is more important than focusing only on the time that they are running. To check this, you can place some straight-sided cups (tuna cans work well) on the lawn here and there when you are watering, some in the trouble spots, and some in the good spots. See how deep the water gets in each cup during your regular session. You might want to see if there is a big difference between the green and yellow areas - which, if there is, would indicate a problem with your sprinkler layout. But the bigger revelation may be that you are actually not putting down enough water, anywhere.

When I did my first "tuna can" test I was astounded at how little water I was actually providing. Just fwiw.

Let us know,
Paul

Are the areas you have trouble with get full sun?

Paul the water rule doesn't apply to places like Tucson, they have to water every or every other day becuase of th epure sand/rock soil, 0 humidity, and 100+ temps. Otherwise it would be dead in a few days.

Noted TW, thank you.

Your welcome Paul. For folks like us east of the Rockies we donÂt always realize the conditions west of the Rockies especially the lower elevation desert southwest. It can really be an alien place when encountered the first time.

I have relatives and biz associates in Phoenix, Flagstaff, and Las Vegas. What strikes you or at least me when I go out there to Phoenix is very few folks have grass yards, even the more upscale neighborhoods. Most who take pride have desert scapes with lots of rocks and some desert plantings and use drip irrigation. A lot just cover their yards in crushed rock or river pebbles, and what is really foreign some of them paint the crushed rock GREEN. What few yards you do see with grass are very small patches sculpted with desert scapes. Drive up to Flagstaff at altitude and it is another whole new world. Then you have the neighborhoods that are either care, or lower to middle class who donÂt do anything, it is just the native sand, rock, dust, and spiders.

Anyway I hope the OP checks back. Bermuda is pretty easy to grow out there as long as you keep it very well watered, and fed. In Tucson with the very sandy soils and yellow Bermuda signals "CHLOROSIS" or lack of iron. My next question would be is it really yellow or tan? Big diference caused by different problems.

Thanks for the comments.

The water soluble Miracle-Gro product I'm using is 24-8-16. It was the only fertilizer I could find at lowes/home depot that had the 3-1-2 ratio recommended by the sod grower.

The water test shows that I'm putting down more than an inch all over the lawn and the soil seems to stay damp down to about 6-8 inches.

It is yellowish green. It seems to still be living, just not growing "up" if that makes sense.

Could it be a problem with soil compaction? I didn't that that would be a big problem is the soil is moist.

We have a very clay heavy soil. For Arizona I'm told it's actually pretty good soil. Prior to our development the area was a cotton field.

The yellowish green is probably due either to low nitrogen or low iron (chlorosis). Since you used a nitrogen fertilizer, the problem is more likely to be low iron.

That doesn't mean that your soil is low in iron, nor does it mean that you can put down iron to solve it (unfortunately).

In the intermountain west, a more common cause of iron chlorosis is that the pH of the soil is too high and, even though there is plenty of iron available, the grass can't make use of it. You could add chelated iron, but if the pH is high enough, you'd need to use eddha chelated iron, which tends to be more expensive and less readily available.

It's difficult to lower the pH over a large area like a lawn. A better approach would be to use greensand (glauconite) if it's available. Adding a lot of organic matter can help bring the pH closer to neutral.

If the water is penetrating to a depth of 6-8 inches, I don't think compaction is an issue. But if you're watering that much three times a week, you're probably watering too much. Too much water is another potential cause of chlorosis. I would cut back to once a week watering, but if the grass starts to show signs of stress (for example if the grass stays down when you walk on it), water it before the week is up. If you've got clay soil and the water penetrates to 6-8 inches, you should be able to get by watering once or at most twice a week.