Lawns add value to our homes, providing an important part of landscape design, safe play surfaces for sports or children's games and natural cooling of the immediate area. But many homeowners could save hundreds of dollars, put fewer pesticides into our environment and wash less pollution downstream if they would satisfy only the true needs of their lawns, rather than marketing myths. Here are a few common lawn myths de bunked:
Myth: Early spring applications of a complete fertilizer is critical for a vigorous lawn.
Fact: You should wait until May to first apply fertilizer. Nitrogen (N) is the element plants need in greatest quantity; buy and apply a complete fertilizer (N-P-K) only when soil test results show low P (phosphorous) or K (potassium). Plain ammonium sulfate is less expensive and does the job just as well.
Lawn fertilizing services often push customers to apply fertilizers too early, probably to "even out" their service schedules. Spring snow melt or rain can carry nitrogen deep into the soil below grass roots. Or, spring rain may wash fertilizers off the lawn, down the street and into the storm sewer, polluting downstream creeks and rivers. Plan your first lawn fertilizer application for mid-May, right before you turn on your sprinklers for the season.
Too-early nitrogen applications can also increase lawn diseases and winter annual weed growth.
Myth: All lawns need pre-emergent herbicide treat- ments.
Fact: Healthy, vigorous lawns will out-compete most weeds. Instead of wasting money on pre-emergent herbicides, hand-pull or spot-spray the few dandelions or Western salsify that pop up in your lawn. Weedy areas in corners and footpaths can be covered with mulch or pavestones.
Pre-emergent herbicides can damage trees and shrubs, although rarely. Although pre-emergent herbicide should stay on or slightly below the soil surface, rain or irrigation water may carry the chemical deeper into the soil, reaching tree or shrub roots. Symptoms include stunted growth, deformed leaves or death.
Myth: Once you have a fungal problem in your lawn, you need to apply fungicide on a regular schedule to prevent further infestation.
Fact: Reducing thatch and watering less often will manage lawn fungi.
Thatch is a spongy layer of dead grass blades and roots directly atop the soil. Annual core aeration encourages thatch decomposition. Thatch thicker than a half-inch stays moist longer after irrigation, so fungus starts growing. Water less frequently so thatch dries between irrigations.
Thatch builds up when lawns are over-fertilized and grass is growing faster than thatch can decompose. Check thatch layers once or twice per season and core aerate once or twice per year to keep thatch under control.
Myth: To have a nice lawn, you must spend a lot of money and time on it.
Fact: Most lawns would be healthier with less fertilizer, less pesticide and less frequent irrigations.
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* MAGGIE WOLF is a horticulture agent for Utah State University Extension in Salt Lake County. E-mail her at maggie.wolf@usu.edu.
Learn more
Learn more about caring for lawns in the Utah State University Extension publication "Basic Turfgrass Care," available at your county USU Extension office and online at http://extension.usu.edu/files/gardpubs/hg517.pdf
