Growing Turf In The Shade
One of the challenges I’m often faced with each growing season is how to grow and maintain turf in the shade. Planting a good shade seed blend is not enough. Usually a season or two after a shady lawn is established, I get a phone call asking me what went wrong. Here are a few things to consider.
First, make sure that it is realistic to even grow grass on the site. The most shade tolerant grass will only tolerate 4 hours of direct sunlight per day. Any less than this and the grass will not survive. Consider pruning, thinning and removing trees and shrubs to improve light and airflow. Trees with dense, fibrous surface root systems like maples will make it impossible to grow turf.
The fine fescues, creeping red, hard, and chewings, have the best shade tolerance. The dwarf turf-type tall fescues, offer a wider blade and more upright growth. Kentucky bluegrass will only tolerate part shade. Do not use annual or perennial ryegrass; blends with rye, even for quick cover, because it will out-compete and kill off the slower growing fescues. It eventually dies within 2-3 months, leaving bare ground behind.
New seeding should be done from mid-August to late September. This will give these slow growers a chance to establish before getting covered with leaves. Cultivate the soil before seeding. Water adequately to prevent the seed and seedlings from drying out and dying. When fall comes, make sure that leaves are removed quickly and frequently and are not left on the turf for any length of time.
Once the grass has established, do not overwater. One inch of irrigation, once per week during “prolonged dry periods” is all that is necessary. Do not irrigate in the afternoon or evening because it will promote disease. Early morning is best. Do not mow shady areas at less than three inches because they need as much blade surface as possible to photosynthesize. Also, do not remove more than 1/3 of the total length each mowing.
Shady lawns need less nitrogen, so do not apply more than two pounds of N per season. Apply one pound in September and one pound in late October/ early November. If you feel the need to fertilize in the spring, I would not put down more than ½ pound of N using a good slow-release product like the Naturesafe 10-2-8. Apply the remaining 1 -½ pounds in the fall. Any readily available N will trigger the grass to grow which in the absence of sunlight will kill it.
A shady lawn will probably need to be reseeded from time to time. April and mid-August to mid-September are the best times to do so. Loosen soil with a garden rake or core aerify larger areas to create good soil contact while minimizing damage to the existing turf. You may still end up with areas where the grass will not grow. If that’s the case, then it may be necessary to convert the areas to a perennial or groundcover bed.
http://www.clemson.edu/extension/hgic/plants/landscape/lawns/hgic1202.html
http://www.ipm.iastate.edu/ipm/hortnews/2007/5-2/grass.html
http://urbanext.illinois.edu/lawntalk/suggested_lawn_mixes.cfm
