In the Carolina Yardstick booklet, we like to encourage homeowners and residents to achieve a "yard" or 36 inches of environmentally friendly landscaping. The lawn, which is such a large area in many Southern landscapes, can really factor significantly in that measurement. I want to address mowing heights, watering, fertilizing and pest control and explain how together they can make a huge difference in the appearance and service of a lawn.
Mowing heights Mowing heights should be set to maximize leaf area of the turf which is grown. Leaves are the factories of the planet and provide food for all parts including the root, shoot, flower and stem.
Research shows that grass root growth is directly proportional to leaf area. More leaves means better developed root systems. You never want to mow grass that is wet or stressed. When you do mow, only remove one third of the leaf at a mowing. Lawn mower blades should be clean and sharp to provide a better healing cut.
Centipede, carpet, Bermuda and Zoysia are mowed at 2 inches, so they should be 3 inches at mowing.
Watering Watering is another way to keep turf healthy, but too much water can be worse than not enough.
As a general recommendation, give established grass about 1 inch of water a week. In the Lowcountry, we have had ample winter and spring rains with cool nights which have helped grass grow. If leaf wetness is extended by weather conditions, it is effective and environmentally responsible to halt irrigation until the grass dries out or until summer temperatures require supplemental water. When leaves stay wet too long, diseases can colonize and cause serious lawn diseases.
Keeping irrigation to an "as needed" basis also will give roots a reason to go deeper in the search for water and minerals. Well-developed roots are going to help turf be more drought resistant.
Fertilization Fertilizing lawns is not rocket science but it is soil science. Take the time to do a soil test before purchasing any chemicals for your lawn or shrubs. Common sense should be the goal when fertilizing, not fancy packages that claim to do everything except take out the trash.
Timing of fertilizers also is very important. The Lowcountry's warm-season grasses do not need to be fertilized when they are not growing, when they are about to go dormant or when they are not yet out of dormancy. My mother in law always said, "Don't wake up the baby, you will be sorry." This applies to warm-season grasses, which should be allowed to wake up slowly. Pushing them can cause a host of problems.
Weed and feed is not a product for Southern lawns. Pre-emergent herbicides keep weed seeds from germinating, so if you had a problem with summer annual weeds this is something that should be applied to your lawn in February or March when it is too early to put down fertilizer. Clemson recommends putting on fertilizer for low maintenance turf at one to two pounds nitrogen per 1,000 square feet a year. The first application is typically in April. If a split application is desired, apply a half-pound to one pound per 1,000 square feet in April and again in August. The rate is slightly higher for high maintenance lawns of Bermuda or Zoysia.
Grass needs nitrogen and potassium to grow healthy leaves and roots. Too much nitrogen can cause excessive growth, succulent leaves susceptible to diseases and insects, and nutrient pollution carried by stormwater runoff. Area soil often is high in Phosphorous, so we don't need to apply more unless a test indicates a deficiency.
Fighting pests Healthy grass will be more resistant to insects and diseases than stressed grass. Pests can be a problem, but cultural controls will go a long way in preventing them.
Always identify the problem pests before using chemicals. Insects are often bird food and most tend to have natural predators unless a population gets out of control. Know what an acceptable level of damage is before using chemicals and use the least toxic product available to give that control.
Laura Lee Rose is a horticulturist for the Beaufort County Extension Service. Contact her at firstname.lastname@example.org.