Bare spots on lawn
Soil PH? Shade! What type grass?
Certified GKH Gardening Expert
Please include photos. It will be very difficult to know what the issue is without seeing the damage. Also, we won't be able to tell you what type of grass it is without a photo, and it can even be difficult with one.
Please include photos and a description of your feeding/watering schedule and any other information that would help us to determine what is wrong with your lawn.