Answer: It sounds like a weedy native grass rather than your cultivated grass so be sure to compare them closely. If it's a weed, pull it out, scratch over the bare soil and then overseed with fresh new seed. If it is not a weed but your turf, I suspect that the soil is either too shady or too compacted to allow deep rooting. You can try to aerate the patches (use a garden fork and push straight down 3-4 inches) then spread compost or sand over the area and water it in. It will be rinsed into the holes and will help the soil retain a little more moisture so the roots will have a nice damp place in which to grow. Then overseed the areas. Best wishes with your lawn!
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