Advice for Shady Lawns

“How do I get better grass in the shade?” is one of the leading questions I get at lawn clinics. Think about it: The lawn you established when your landscape trees were young was likely better adapted to sunny areas, and now has thinned out as your trees have grown. Here are some basic tips to improve your shady lawn:

Grow the right grass: For cool-season grasses, here is the ranking for shade tolerance from most to least: Fine fescue, Tall fescue, Kentucky Bluegrass (some varieties more tolerant than others and are as shade-tolerant as fescues), and finally Perennial ryegrass. For warm-season grasses, here is the ranking for shade tolerance from most to least: St. Augustinegrass, Zoysia, Bahiagrass, Buffalograss, Centipedegrass, with Bermudagrass least tolerant.

Fertilizing:It is important to feed shady lawns in early spring and in fall before tree leaves develop or after leaves fall from your trees. When you fertilize while the lawn receives sunlight, you maximize photosynthesis, which builds carbohydrate reserves in the grass roots to help when sunlight is limited during shady times. The best cool-season grass shady lawns that I have seen have all been fed twice in fall: September and Early November.

Watering:This is tricky. Lawns can get by with less water in shade, however some trees are very aggressive at stealing whatever soil moisture is available thereby keeping the grass under water stress. This means you need to water when the grass is dry, but hold off if the soil is moist. Look for signs of dry grass (such as a change in color from bright green to the dark-colored green with long-lasting foot prints caused by the grass not springing back to the upright position after being walked on). If your grass and soil stays wet for a long time after watering, reduce the amount. If the grass quickly shows the drying out symptoms, then increase. Remember infrequent deep watering (no more than twice a week) is better than daily shallow watering.

Mowing: Mow at one of the taller settings so that your cool-season grasses are about 3 inches after cut and your warm-season grasses are about 2 inches (exception is St. Augustinegrass which should be cut at the higher 3 inch setting).

Thatch: You do not generally have to worry about thatch in shady lawns as it generally stays below a half inch. Since there is less thatch to protect the grass plant crowns, try to limit the foot traffic in shady areas.

Too much shade for grass: If you decide to plant one the shade grass seed blends or to shift to one of the more shade-tolerant grasses listed above, just remember that you still need at least 4 hours of filtered-sunlight a day to grow. You can help by trimming low hanging tree branches. If the shade is from a building giving you no filtered sunlight, then grass will be tough to grow. When you have less than 4 hours of filtered sunlight, you may need to consider an alternative to grass such as Pachysandra, Vinca or Liriope. Your local nursery can help you choose the best shade-loving groundcover for your area.  A second alternative is to mulch areas under trees where grass will not grow.