Most types of grass require full sun to sustain normal growth. They thin out and become susceptible to diseases when planted under shade trees. A few grasses tolerate shade, but they require different cultural practices that those that require full sun.
Shade-tolerant, cool-season grasses, such as tall fescue and fine fescue, do well in the Northern United States. Shade-tolerant, warm-season grasses, such as St. Augustine and zoysiagrass, do well in the Southern United States.
Cut the grass at the highest recommended mowing height to make more of the blade surface available for photosynthesis in low-light situations. Irrigate grass plants deeply to reduce competition with tree roots for water. Remove tree limbs, leaves and grass clippings that prevent sunlight from reaching the grass.
Many seed mixtures include Kentucky bluegrass, which is not suitable for growing under shade trees. Select seed mixtures that include at least two varieties of shade-tolerate species, such as rough or supine bluegrass.