When Is It a Good Time to Fix Patchy Lawns?

Warm-season Grasses

• Late spring is the best time of year to patch warm-season grasses; wait until the soil has warmed up and the grass is beginning to green up. Warm-season grasses are best suited to areas of the country where summers are hot and either dry or humid, and where winters don't bring freezing temperatures. Common turf species and cultivars include bermudagrass (Cynodon spp.), which grows in U.S. Department of Agriculture plant hardiness zones 7 through 10, bahiagrass (Paspalum notatum), also hardy in USDA zones 7 through 10, St. Augstinegrass (Stenotaphrum secundatum), which grows in USDA zones 8 through 10, and zoysiagrass (Zoysia spp.), which is hardy in USDA zones 6 through 9.

Cool-season Grasses

• Cool-season grasses are tough enough to handle below-freezing winters in areas where summers are typically mild. During fall and spring, these grasses shine due to their color and growth. Early spring or early fall is the best time to patch cool-season grasses. Species include Kentucky bluegrass (Poa pratensis), which grows in USDA zones 2 through 7, fescues (Festuca spp.), also hardy in USDA zones 2 through 7, and rough-stalked bluegrass (Poa trivialis), which grows in USDA zones 4 through 7.

Weeds

• A few preparations may be required, depending on the area you're reseeding. For example, if you have perennial weeds growing in the area or that are prone to the area you're reseeding, kill these first using a non-selective herbicide such as glyphosate. For small areas, use a spray bottle with a targeted stream setting to prevent spraying healthy turf or prized perennial flowers. In general, wait three or so days (consult the label to make sure) before laying your grass seed.

Planting

• Lay 2 to 3 inches of compost over the planting area and till it into the soil to a depth of at least 6 to 8 inches. Tilled and nutrient-rich soil will give your grass seed an ideal growing medium. Choose only high-quality, weed-free grass seed that matches the turf growing in the rest of your lawn. Gently rake the seed so that it's covered by 1/16 to 1/8 inch of soil. Cover the area with straw to hold in moisture and prevent the seed from blowing away. Straw can also protect the seed from hungry birds or critters. Water the grass seed thoroughly and keep it moist throughout germination and sprouting.