Growing grass in heavily shaded areas is very difficult because turf needs sunlight to thrive. Grasses that do not get sufficient light are not as healthy or hardy because their roots, shoots and rhizomes don't grow as much as they should. This makes the grass more prone to stresses such as drought, heat, cold and wear and tear. With the help of site preparation and shade-tolerant grass, though, even novice gardeners can get grass to grow in shaded yards. Grass seed is an effective way to go because sod is much more sensitive and less likely to survive.
Prune heavy trees to let more light into your yard. Too much shade thins out grass and can even kill it completely. Trim 35 to 40 percent of the lower limbs to boost light penetration without effecting the tree's appearance.
Choose a shade-tolerant grass seed. Shaded grasses are more succulent, which means they contain more water. Some appropriate varieties are red fescue, St. Augustine and chewings fescue. Red fescue and chewings fescue are cool-season grasses and should be put in the ground in early to mid-fall. St. Augustine is a warm season variety that should be spread in the spring.
Get rid of all debris in the yard with a rake. Remove weeds because they will compete with the new grass.
Till the planting area to aerate the soil. Work under the trees, being mindful of the roots below. Try to loosen the soil to a depth of 4 to 6 inches. Adding air pockets will help the grass seed germinate.
Fill a hand spreader or broadcast spreader with the appropriate amount of grass seed for the space. Use the seed bag to determine the rate. Spread it evenly so the seeds can germinate without competing for nutrients.
Rake the seed with the back side of a metal rake. Cover it with 1/4 to 1/8 inch of soil. This will protect it, keep it in place and encourage germination.
Water the sown seed at least once a day to keep it moist. You may be able to water it every other day because it is cool under heavy tree cover. Use the touch test to determine when the seed needs more water. Keep the soil moist until the seed germinates.
Apply a fertilizer that is high in phosphorus once the grass is established. This will help the roots develop strength and improve the chance of survival.
Keep the grass in highly shaded areas one-third higher than in other areas. This will cut down on stress by letting the grass blades suck in more sunlight.
Water the grass deeply but infrequently. If you water the grass lightly, the tree roots will come to the surface and steal nutrients from the grass. Watering shaded grass too much increases the chance for disease.