Answer: Brown areas in the turf can be caused by a number of things. A heavy thatch build up will keep water from penetrating the soil; grub feeding can kill grass roots; cool season grasses will die out in the warm summer months; fungal disease can produce large brown areas in lawn.
We'll start with the easiest and move on... check to see what turfgrasses you are growing. Warm season grasses such as bermuda will green up in the summer and die back in the cooler fall and spring months - cool season grasses will remain green in the spring and fall months but die out in the summer months. No amount of water will keep cool season grasses green in the summer months.
Second on the list is a thatch build up. Dig a shovelful of soil out and check to see whether there is a half inch or more of thatch (dead stolons and stems above the soil surface). If so, it can keep nutrients and moisture from reaching the soil. It will need to be removed (power dethatchers can be rented).
Grubs can really wreak havoc on lawns. They feed on the roots of the turf. Dig out a 12 inch square of turf, roots and all, and inspect for grubs. You'll seed them either hanging onto the roots or just at the soil surface. Grub control products will take a few weeks/months to kill the pests but your lawn will improve eventually.
Fungal diseases can be identified by inspecting the leaf blades. Spots, raised areas, collapsed tissues are all signs of a fungal disease.
The final thing to test is the soil compaction. Compaction will keep grass roots from penetrating the soil. You can rent a core aerator and then spread a thin layer of sand or compost over the lawn. The sand or compost will work its way down into the soil with rainfall or water from the hose and help loosen the soil.
Hope this information helps you determine just what might be causing the browning areas in your turf.
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