Maintaining Turf
By Janet Hartin
Excerpted from Become and Landscape Company Owner' by Janet Hartin (fabjob.com).
Keeping turf in good condition is very important. It not only looks more attractive, but well-maintained lawn and sports fields recover from wear, pest damage, and mechanical injury much better than poorly maintained ones. The popularity of outdoor sports has skyrocketed in many areas, and this over-use causes the grass to suffer from wear and tear and soil compaction. A properly maintained sports field is resilient and provides a safe surface, which increases enjoyment of the game and prevents needless injuries and lawsuits.
A good turf maintenance program includes proper irrigation, aeration, thatch control, fertilizing, mowing, and pest management. Let’s talk about thatch, soil compaction and fertilizing.
Thatch and Soil Compaction. Thatch (that partially decomposed organic layer of grass roots and stems that you can see on top of the soil in a grass planting) thicker than ½ inch invites problems and should be removed. It tends to be worst on Kentucky bluegrass and Bermuda. A little thatch is good. It provides cushioning for sports play and should be left alone. Once thatch problems start, though, they’re hard to stay on top of, so get your ruler out!
You have a couple options for thatch control. In some cases, you’ll want to use both. One option to rent a verticutter or power rake and use it gently and shallowly. Rather than doing too much at one time, it’s better if you have a heavy case of thatch to not remove it all at once. Be sure to compost what’s removed and use it as a mulch or soil amendment. The other option is core aeration, which also opens up compacted soil. Sports fields, both sand and clay, usually have very compacted soil. So do clay soils even without much activity. Removing soil cores (aerating) with a rented core aerator adds oxygen and improves drainage. Core when the grass is actively growing to help it recover from any injury. Cool-season grasses should be cored in fall or early spring and warm-season grasses in late spring or early summer. To do it right, use an aerator that removes plugs, not one with solid tines. Rent one that removes long plugs (at least two inches) and is 1/2-inch inch or more in diameter. The machine drop the removed cores onto the soil. You can leave them alone or speed up the decomposition process by dragging a piece of cyclone fencing over them. Mowing over the cores with a rotary mower dulls the blades and isn’t such a good idea. Another option is to gently break up the cores with a power rake .
Fertilization. Nitrogen is important for green, healthy turf, especially during the season that it’s most actively growing. Nitrogen-deficient turf grows slowly and doesn’t fill in well, turns yellow and doesn’t hold up to traffic well. One or two applications of a complete fertilizer that contains nitrogen, phosphorus, and potassium is recommend annually. Five to six additional pounds of actual nitrogen per 1,000 square feet are required throughout the growing season to maintain high quality playing fields and golf courses. Lawns and sites that aren’t used so intensely only need three or four pounds over the course of a year. Grasscycling (leaving clippings on the lawn) recycles nutrients, reducing nitrogen requirements by 20-25%.
It’s important to apply enough nitrogen without overdoing it. Overfertilization can add to thatch buildup and increase mowing and water requirements by promoting too much growth. And, nitrogen can leach below the root zone and end up polluting rivers and streams, especially in sandy soils. Because of this, it’s a good idea to avoid fast-release fertilizers entirely in favor of slow-release nitrogen sources (sulfur-coated urea, IBDU or natural organic-based fertilizers) on fast-draining sandy soils.
Under-fertilization can present problems too, leading to weak, unhealthy grass. Lawns that don’t green up after an application of nitrogen may need other nutrients, like phosphorus or iron. A soil test will pinpoint which ones are needed and how much to apply. Remember that soils may have too high or low of a pH to grow healthy lawns, so have that tested too, and follow recommendations from the lab. Balanced fertilizers that contain nutrients besides nitrogen, such as phosphorus, potassium, and iron, should be applied a couple times of year. But, bulk of the nitrogen can be applied by itself in separate applications during the active growing season.
