This aggressive chemical schedule is controversial to some experts, however. While the pure nutrients in lawn fertilizers—the nitrogen, phosphorus, and potassium—are not in themselves highly toxic, a problem arises when excessive amounts are used. Nitrogen run-off from lawn fertilizers can reach ponds, lakes, and rivers, causing algae blooms that reduce water oxygen levels and kill fish and other aquatic life. And some of these lawn care products combine basic fertilizer nutrients with other chemical herbicides and pesticides that are more highly toxic. When these chemicals run off lawns into water supplies during rainstorms, the effects can be even more dramatic. The EPA notes that these herbicides and pesticides are known to cause cancer, immuno-response deficiencies, neurological diseases, and birth defects in animals and people. Thus, there is a conflict between homeowners who very much want that country-club, ultra-green, weedless lawn and the more environmentally conscious consumers and advocates who want to avoid damage to the environment. One camp, bolstered by the lawn product industry, will recommend applying fertilizers of various types up to four times per year, while the other side will argue for feeding very rarely, if ever, and never applying products containing weed-killing chemicals.
A Traditional Fertilizing Schedule
Take a look at a sample schedule from Scotts for a Northern lawn composed of a mixture of bluegrass, ryegrass, and fescue. Scotts suggests a four-part schedule for fertilizing lawns. The exact schedule will depend on where you live and your grass type. Ask your local county extension office for tips tailored to your specific situation. Before fertilizing lawns with any commercial products, read the instructions carefully (or ask someone at the store for details). A particular product may not be suitable for your type of grass.
Problems With the Traditional Schedule
Despite its long popularity, this schedule for lawn fertilizing runs contrary to the recommendations of many turf-science experts. Applying this much nitrogen to a lawn can create deep green top growth but often at the expense of healthy root systems. And such heavy feeding also nourishes weeds, requiring the application of heavier doses of weed killer to keep pace. Of particular concern are the weed-and-feed products that combine fertilizer with other weed-killer chemicals. A major problem with these products is that the proper timing for feeding a lawn is generally different from the ideal time for killing weeds. Applying combination products generally means that excess chemical is likely to run off into local water supplies. The herbicide normally found in these products is a powdered formulation that contains 2,4-D, mecoprop, and dicamba—all chemicals known to cause health and environmental problems. If you must use chemicals, the argument goes, it is much better to apply a pure weedkiller in conservative doses at the optimal time for weed control and pure fertilizers at the ideal time for feeding the various turfgrasses. The environmental problems with weed-and-feed products are so well documented that some countries have banned their use. In Canada, for example, weed-and-feed lawn care products have been banned since 2010. In the U.S., scattered jurisdictions have also banned these products.
Best Application Practices
If you’re intent on the traditional approach, make sure to keep your applications at, or less than, the label recommendations. Lawn chemical companies would love for all consumers to apply heavy doses of fertilizer, but the reality is that lighter applications usually give the same results, and may even make for a healthier lawn. Choose slow-release formulations that will continue to feed for several weeks, and apply them when the grass is wet and the soil is damp but not immediately before heavy rains are expected. Heavy storms can quickly wash your fertilizer into storm drains before it can be absorbed in the soil. Use a drop spreader to apply fertilizers, not a broadcast spreader that may cast fertilizer pellets onto sidewalks, driveways, or streets. Fertilizer on hard surfaces will easily wash into storm drains and water supplies at the first rainfall.
More Organic Lawn Care
If you are intent on achieving that deep emerald-green lawn, it is a more responsible approach to limit your feeding to three light applications times a year and to always avoid the weed-and-feed products that add herbicide chemicals to the formulations. A modest application of balanced slow-release fertilizer in late spring, late summer, and late fall is a reasonable approach. But, if you want to be more organic about your lawn-care practice, here are some tips to follow:
Replace at least one feeding by top-dressing with compost rather than chemical fertilizer. Compost has many advantages as a plant food, since it improves soil texture as well as providing nutrients. Simply rake a thin layer of compost over the lawn, and water it in. Some homeowners achieve great results using nothing but compost for every lawn feeding. Use a mulching mower, which will chop up grass clippings and return the nitrogen back to the soil. It’s estimated that using a mulching mower all season can take the place of one entire feeding cycle with chemical fertilizer. Consider turf grass alternatives. The mono-culture lawn that contains only blue grass and fescues is a relatively recent landscape trend and a somewhat unnatural one, according to some experts. There was a time not along ago when a more diverse lawn culture that included clovers and other types of grasses was regarded as the ideal. For example, a good choice for dry conditions is to grow tall fescue grass, which is drought-tolerant. Knowledgeable homeowners are increasingly returning to lawns that are less finicky and include other plant species, especially white clover. Though regarded as a weed by some, white clover makes for an excellent lawn, since it requires less moisture, grows more slowly, and needs less feeding than turf grasses. In fact, it has a unique ability to “fix” nitrogen in the soil and therefore requires much less, if any, artificial feeding. Finally, white clover is an excellent plant for a bee-friendly yard, since the white flowers serve as a favorite food source for these insects. By mowing at a slightly higher level, you can preserve the flowers and make your yard a haven for threatened pollinator bee populations.
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