Grass needs sunlight and air to survive. Most lawn grasses need 4-6 hours of direct sun to survive. Some shade-tolerant grass types grow as long as light hits that 4 hr quota—and the light doesn’t have to be full sun. Four to six hours of dappled or filtered sunlight can fuel the growth of a healthy lawn. When soil gets compacted—from foot traffic, mowing and the like—oxygen can’t reach the microbes that break down or-ganic matter to enrich the soil. To keep your lawn healthy, it’s a good idea to aerate it periodically to open up the compacted soil. Roots can be damaged when temperatures are above 85°F. The combination of warm temperatures and lack of moisture can cause cool-season grasses to go dormant and turn brown during dry summers. Unlike CLEAR plastic, black plastic blocks out light, smothering grass roots and preventing new growth.