Originally Published In The Deseret News -- Wednesday, April 6, 1994
Don't Mow Too Short. Leave Clippings On The Grass: They're Beneficial.
April is National Lawn Care Month, although I suspect most gardeners do not need this designation to realize that it is time to get their lawns in shape.
Lawns in the United States cover 25 million acres. About 100 million people operating 61 million lawn mowers keep lawns looking neat and trim. It is estimated that in North America about 1 billion hours are spent on lawn care every year. Ask teenagers, who you try to get to mow the lawn each week, and they will claim they spend most of that 1 billion hours personally mowing your lawn.
There is a payback for all of this time, expense and work. Lawns are wonderful play areas for both children and adults and are the least expensive groundcover to install and maintain. They provide security zones to keep burglars, insects and rodents away, as well as create a firebreak. Lawns also provide many environmental benefits because the root system holds the soil and purifies water leaching through it. They trap dust and smoke particles and act as evaporative coolers to lower the temperature of the surrounding air. Living grass plants produce oxygen and improve soils. Although it takes time and money to grow a lawn, turfgrass provides a durable growing surface that is not available from other plants.
Attention to details makes the difference between a healthy, weed-free lawn and one requiring constant attention and expense. One of the biggest mistakes of growing a lawn is to mow it too short. While bentgrass tees and greens on golf courses are mowed daily at heights of about a quarter-inch, that is not how lawns should be cared for. Most bluegrass lawns do best when mowed at 2 1/2 to 3 inches. Higher mowing reduces weed problems and moisture requirements. Many seeds, such as crabgrass, need light to germinate, and taller turf discourages these seeds from germinating. Taller turf also has a better root-to-shoot ratio, so it is not under the same stress as closely mowed turf.
Soil compaction is a major problem with turfgrass. Normal soil contains 25 percent air. Soils under turfgrass often have far less than that because of continual traffic and use as playing fields or other surfaces. Coring aeration is beneficial on highly compacted soils. Aeration can be done anytime during the growing season as long as the soils are moist. In addition to allowing oxygen to penetrate into the root zone, aeration helps decompose thatch. Thatch is composed of dead grass roots and rhizomes that accumulate between the base of the grass plant and the soil. Short mowing, excessive water and excessive fertilizer all increase thatch buildup.
One common misconception is that leaving the clippings causes the thatch to build up. Grass clippings do not contribute to thatch. They are 85-90 percent water so they decompose quickly and return 20 percent of their dry weight to the lawn as nitrogen. This natural recycling process is a way to reduce the time and effort spent in caring for your lawn and still have a healthier, more natural lawn.
All of these cultural practices reduce problem weeds but may not totally eliminate them. Gardeners facing serious weed problems may have to do more. Pre-emergence herbicides should be applied prior to April 15 to control crabgrass, spurge and other annual weeds. Dacthal, pendemethalin and betasan are all common crabgrass controls. These require two applications at six-week intervals to control crabgrass and spurge. Galleria and Team are longer-term products that can be applied much earlier to give seasonlong control of these weeds from seed.
Fertilization is one of the most important practices to keep a good, healthy, weed-free lawn. Normally grass is extremely competitive and crowds out many weeds. Apply high nitrogen fertilizers three to four times per year to keep the lawn adequately supplied with nutrients. The natural tendency of many homeowners is to pour on excessive fertilizer when they think about it, but a much better method is to apply small amounts of fertilizer evenly throughout the growing season. This same process is accomplished by using a slow-release fertilizer a couple of times per year. Broadleaved weeds also can be a problem in the lawn. Dandelions are the most prominent but certainly not the most difficult to get rid of. Apply a broadleaved-leaf killer as soon as the weeds start to actively grow. Weed killers should not be needed on a frequent basis. If they are, check cultural practices to find the problem and correct it.
Common-sense lawn care should be the watchword for all gardeners. Significant reductions in water, fertilizer and pesticide use are possible by simply monitoring the turfgrass conditions and providing the right ingredients at the right time. Save your time and money, and have a more attractive lawn, by working smarter not harder on your lawn.
© 1998 Deseret News Publishing Co.