Most yard and garden topics don't arouse serious controversy. Very few gardeners have come to blows over whether daylilies are better divided in spring or fall. But one issue upon which opinions differ is the use of chemicals on lawns.
Most homeowners would agree they prefer lawns rich in color, uniformly thick and free of weeds and disease, but views differ on whether to use chemical fertilizers and weed sprays to accomplish the task.
For many lawn owners, applying fertilizer and herbicides is standard practice. Others prefer lawn care that doesn't involve chemicals.
Most people can probably agree that misuse or overuse of chemical fertilizer or pesticides is dangerous if excess products wash off lawns and end up polluting rivers, or endangering humans, pets or wildlife. Most lawn owners probably further agree that judicious use and safety are important anytime pesticides are applied.
To cut back, homeowners can choose total elimination of all chemicals, or reduce the amount of fertilizer and pesticides used. North Dakota State University, University of Minnesota, Cornell University and University of Illinois agree on the following lawn care practices that keep grass healthy and reduce the need for weed sprays and heavy fertilizer additions.
• Raise mowing height to three inches. Grass roots remain cooler, moisture is conserved and weeds are shaded.
• Instead of bagging clippings, allow them to filter in. Nutrients released as grass decomposes equal one application of fertilizer per year.
• Reseed bare spots to prevent weeds from filling the voids.
• Encourage healthy, deep roots by watering deeply and less often. Apply one inch of water per week in one application.
• Avoid watering at night. Diseases arise more easily the longer grass remains wet. Best time to water is between four and eight o'clock a.m. Evaporation is less, yet grass dries quickly as sun rises.
To eliminate chemicals, follow these recommendations:
• As chemicals are discontinued, soil becomes more biologically active with microbes and earthworms. Healthy soil is the basis for a self-sustaining, vigorous lawn that doesn't require other additives.
• While the lawn transitions away from chemicals, it might not look as good the first growing season. It can take several seasons for soil microbe population to increase, which is important for releasing nutrients from the soil's organic matter.
• Allowing clippings to filter back into the lawn becomes the main source of fertilizer. Lawns can also be top-dressed with a thin layer of compost, manure or other organic fertilizer.
• Some weeds can be expected until grass health improves. Hand weeding may be needed. Vinegar solutions, boiling water and flame weeders can be used, but weeds must be targeted carefully, because these products also kill grass.
• Products containing corn gluten meal have proven effective in preventing weed seeds from sprouting in lawns.
To simply reduce chemicals, follow these guidelines:
• Fertilize in the fall around Labor Day when grass plants make maximum use of extra nutrition. Skip spring applications, or fertilize sparingly around Memorial Day.
• Apply weed-killing herbicides at safest, most effective times, such as in late May when weeds are actively growing, temperature is in the low 70s and the wind is calm. Fall is the best time to spray perennial lawn weeds.
• Spot treat weeds, rather than spraying the entire lawn, when there are only scattered weeds.
• Skip routine applications of lawns insecticides, unless a problem is actually detected.
Don Kinzler, a lifelong gardener, worked as an NDSU Extension horticulturist and owned Kinzler's Greenhouse in Fargo. Readers can reach him at email@example.com.
He also blogs at " target="_blank">growingtogether.areavoices.com.