By Debbie Nelson, Master Gardener, U of M Extension Service, Hennepin County
For many people, most of their time spent gardening is spent on maintaining their lawns. For some their lawn is their only garden. Yes, a lawn can be considered a garden, a garden with only one type of plant–turf grass. It is estimated that 1000 square feet of lawn contains approximately one million grass plants. Mowing, fertilizing and watering all those grass plants is definitely the most time consuming gardening we do. But there are practices we can use that will reduce the time and resources put into our lawns, and make them more environmentally friendly as well.
Mowing is probably the most time consuming chore. Time spent mowing can be reduced by leaving your grass at an optimal height of 2½ to 3 inches. That is because the rule of thumb for mowing is to remove no more than 1/3 of the grass blade to maintain healthy plants. A lawn that is kept at 2½ inches need only be mowed after it has grown an inch. A lawn that is kept at 2 inches or less needs to be mowed after it has grown ½ inch. Assuming the same rate of growth, that alone cuts your time spent mowing in half. And there are other reasons to maintain the lawn at this height. The taller grass allows the roots to grow deeper where they can access more water and nutrients, making the lawn more drought resistant and able to withstand other environmental stresses. An additional bonus to longer grass is that it shades the soil and roots which it makes it difficult for weed seeds, especially crabgrass, to germinate. This will reduce your need to apply herbicides to control weeds. It is also important to keep your mower blade sharp, so that grass blades are cut cleanly. Raggedy grass edges are more susceptible to disease and lose more moisture to evaporation. Clean edges will reduce the time spent treating lawn diseases and watering.
Leaving grass clippings on the lawn can eliminate one fertilizer application per season, reducing the time spent on that chore. However clippings should only be left if they are 1 inch or less, where they can fall beneath the blades and decompose quickly. Clippings greater than 1 inch generally sit on top of the lawn where they are not only unsightly but can also shade and/or smother the grass. These should be raked up and composted. Clippings that fall on the sidewalks or driveways should be swept up so that they do not wash into the storm water catch basins and into our lakes, creeks and river contributing to algae growth.
You should not fertilize until you have a soil test, so that you are not adding unneeded nutrients. Plants generally need 18 elements to grow well. Nitrogen (N), Phosphorous (P) and Potassium (K) are considered the primary macronutrients because they are used in larger quantities than the others. The other 15 are used in trace amounts and are generally available in most soils. A soil test can tell you which elements may be missing in the soil and need to add.
Wait before you water. Most varieties of turf grass in Minnesota can withstand some drought. Kentucky bluegrass will generally go dormant in hot, dry conditions and while it may turn brown it will green back up when watered. Fescues usually don’t go dormant but will simply reduce their rate of growth during the hot, dry summer months. If there is no rain for seven days and you want to maintain a green lawn you should probably water. When you do be sure to do so efficiently. The best time to water is in the a.m., when the temperatures are cooler and the winds are lighter, so that less water is lost to evaporation. Water close to the ground to reduce the loss of water to evaporation and wind. Water slowly and deeply to preferably to a depth of 5 inches– ½ inch of water should wet a sandy soil to that depth but it will take 1½ inches for clay soil. Watering to this depth will encourage deep root growth and result in less frequent watering. And be sure that you are only watering the grass and not impervious surfaces which send our precious water resources down the drain.
Change a few of your lawn care practices –you will spend less time and resources, and produce a more environmentally healthy lawn.