The Other Mike wrote:
Water on even days for about 30 - 45 minutes per zone (depending on
the heads of the zones).

There's one problem.

You should be watering once a week, one full inch. If you have run-off
before you can put down a full inch, then you need to aerate.

Never fertilize in the summer. The grass is trying to go dormant. Watering
one full inch once a week will usually stop that, but you don't want any of
the grass's energies going towards the kind of new growth that fertilizer
will encourage.

Also, mow your grass higher than most people seem to think. Two to three
inches, depending upon the mix. Mow often enough that you never have to cut
off more than 1/3 of the blade to bring it back to the desired height. Use a
mulching blade, and leave the clippings on the lawn, and you may not even
need fertilizer.

Note that your watering every other day has likely encouraged shallow roots,
and since this is already summer, it's too late to encourage the deeper root
growth that proper watering would encourage. To keep your lawn green with a
shallow root system, you may have to change to watering every day, or even
twice a day until fall. You would probably be better off letting it go
dormant for the summer, and overseed it in the fall.

A freshly seeded lawn (or new sod) needs more frequent watering, but once
root growth begins, weaning off of the shallow watering pattern is needed.
Shallow roots dry out too fast.

--
Warren H.

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