Watering is one of the most often misunderstood aspects of turfgrass culture. Often, watering on turf areas is too frequent and too light. Frequent, shallow watering encourages shallow rooting, soil compaction, thatch accumulation, and weed seed germination. Enough water should be applied in one application to wet the soil to a 6-inch depth. This can be checked by probing the soil. After a few times you should develop a feel for the amount of time and water required for deep watering. If the area begins to puddle and run-off is occurring, stop irrigating and allow the water to soak into the soil. It may be necessary to repeat this cycle several times before proper irrigation is complete. Irrigating only when turfgrasses show the first visual symptoms of water need and then watering deep will encourage deep rooting. Early morning is an ideal time to irrigate.
Turfgrass plants absorb oxygen and emit carbon dioxide through root surfaces. An adequate amount of air space in the soil is needed to provide aeration and proper soil water movement into and through the soil. Due to heavy use, the upper 2 to 3 inches of soil may become compressed into a more dense, hard soil mass, restricting air and water movement.
Weeds interfere with the beauty and function of turfgrass areas. However, a small number of weeds in a lawn is tolerable. Weeds may indicate the turfgrass community has been weakened by some environmental condition, pests, and/or improper maintenance activities. A healthy turfgrass is the best defense against weed infestation. Herbicides are important tools for controlling weeds in turf, but repeated severe occurrence of weeds may reflect underlying problems that are not correctable with herbicides. The first step in weed control is a management program that produces a dense, vigorous, healthy turf of an adapted turfgrass variety by mowing, watering, and fertilizing properly. Severe insect and disease attacks create openings in turf coverage that will allow weed invasion. These problems should be controlled as they arise.
Annual weeds complete their life cycle in one growing season. They come back each year from seed. Crabgrass, goosegrass, foxtail, and sandbur are summer annual grassy weeds. Knotweed and spurge are summer annual broadleaf weeds. For summer annual weed control with herbicides, apply either a preemergence herbicide two weeks prior to germination (crabgrass and foxtails are effectively controlled with preemergence herbicides and their germination can range from late March to early May, depending on location and year) or by the application of postemergence herbicides soon after their emergence (May and June) when weeds are young and actively growing. Postemergence control of summer grassy weeds is with organic arsenicals (AMA, DSMA, MSMA, Crabgrass Killer Formula II, etc.) and postemergence, herbicide and fertilizer combinations. Normally, two to three spray applications, spaced 10 to 14 days apart, are required for effective weed control. Nonselective postemergence herbicides kill all actively growing plants. Examples include Roundup, Roundup Pro, GLYFOS, Kleenup, Finale, Diquat, and various “weed and grass killer” formulations. Always read and follow all pesticide label instructions.
The warm-season turfgrasses are cut higher in the fall to provide insulation for low temperatures. When they are growing during the summer, they are cut lower to promote lateral spread and a “tight” turf. Cutting turfgrasses below their recommended height will discourage deep rooting. Cutting too low may cause the turf to thin, because it becomes less able to withstand heavy traffic and environmental stresses such as low soil moisture and extreme temperatures. Cutting bermudagrass above its recommended height may produce a stemmy turf, characterized by leaves being produced near the end of upright stems. This kind of turf is prone to scalping. Turfgrasses grown under shady conditions should always be maintained at a slightly higher cut in order to increase leaf area to compensate for lower light levels.
Ideally, turfgrasses should be mowed on a schedule that is based on the amount of plant growth between mowings. This will depend on the level of soil moisture, nutrients, and temperature and the amount of sunlight. Since these conditions fluctuate from week to week, it follows that plant growth also fluctuates. Therefore, the ideal time to cut turfgrasses is at a point so that no more than about a third of the leaf area is removed at any one mowing. This means cutting U-3 bermudagrass at 1 inch each time it reaches 1.5 inches and cutting Tifgreen bermudagrass at 0.75 inch each time it reaches 1 inch.
It is preferable not to bag grass clippings since collecting clippings removes valuable nutrients from the lawn. Regardless of the type of mower used, it is essential that mowing equipment be kept sharp and in good operating condition. Dull, improperly adjusted equipment bruises leaf tips, reduces growth, and causes a dull-cast appearance over the turf area due to frayed leaf blades. Other mowing practices should include varying the mowing pattern throughout the growing season to distribute wear, reduce soil compaction, and improve turf appearance. Secondly, make turns on sidewalks and drives or make wide turns to avoid tearing the turf. Lastly, avoid mowing wet grass. It is harder to obtain a quality cut, clippings form clumps on the mower and turf, and disease organisms are more likely to be spread.
Healthy lawns depend on many factors including adequate water for cell enlargement and evaporative cooling, sunlight and carbon dioxide for energy production, and oxygen for respiration. Lawn growth also depends on nutrients or essential elements absorbed by roots from the soil. When natural soil processes do not provide adequate supplies of these essential elements, fertilizer can be applied to maintain optimum turfgrass growth. The purpose of fertilizing a lawn is to add the necessary nutrients in the required amounts and at the proper time to achieve desirable lawn qualities and healthy turfgrass plants.