Things You'll Need. Mow your lawn to height of 2 1/2 inches. If you are mowing it shorter than this, it is likely to turn brown and take on a burnt appearance. Water the burnt spots and entire lawn with 1 inch of water weekly. If your lawn is littered with burnt spots, it may be caused by lack of water. In especially hot months it is necessary for the soil to be moist approximately 4 to 6 inches down. Replace permanently damaged burnt spots.