Home and Yard
Rethinking yard care can save time and money. Many sources of urban water pollution originate right
at home. Excessively or improperly applied fertilizers and pesticides can wash into storm drains and
ditches. These chemicals then travel to lakes and streams. Clearly, there is a need to rethink what
we're doing at home if urban waters are to be clean and usable.
For some, yard care can be a very rewarding pastime; for others, it is merely a chore necessary to
protect the investment in a property's appearance. Regardless of motivation, most homeowners rely,
at one time or another, on lawn and garden pesticides and fertilizers. Unfortunately, routine use
of these chemicals threatens to open a Pandora's Box of unintended environmental consequences.
Following some common-sense guidelines, however, will bring about healthy lawns and gardens and
minimize environmental problems.
Excessively or improperly applied fertilizers and pesticides can wash into storm drains and ditches.
These chemicals then travel to lakes and streams. Clearly, there is a need to rethink what we're doing
at home if urban waters are to be clean and usable.
- Healthy lawns, trees and shrubs add to the beauty and value of a home. They also keep our lakes and streams clean by allowing rainwater to filter into the soil rather than running into storm sewers. Maintaining healthy lawns and landscape plants, however, often requires the use of fertilizers and improper fertilizer use can cause water pollution.
- Fertilizers, leaves and grass clippings contain nitrogen and phosphorus. When these nutrients wash into lakes and streams they promote unsightly algae blooms and lower dissolved oxygen levels in the water.
- Fertilizer carelessly applied on one lawn can be a waste of the homeowner's money. On hundreds or thousands of lawns, careless over-application creates problems for local streams and lakes.
- The label on a fertilizer bag has three numbers indicating the percentage (by weight) of the three nutrients most essential to healthy lawns. Nitrogen (N) is always listed first, followed by phosphate (P2O5), which supplies phosphorus, and potash (K2O), which supplies potassium. Therefore, a 25 lb. bag of 25-4-5 fertilizer contains 25% (6.25 lbs.) nitrogen, 4% (1 lb.) phosphate, and 5% (1.24 lbs.) potash. The remainder is made of ingredients such as sand or ground limestone.
- Never use fertilizer unless a soil test shows you need one. Call 608-224-3700 to learn more about how to test your soil. Keep in mind that soil needs for your garden will likely vary from your turf's needs. Fertilizing when your lawn doesn't need it is a waste of your money.
- Most organic fertilizers contain relatively low concentrations of plant nutrients compared to synthetic fertilizers and release nutrients more slowly. Slow-release fertilizers provide a lower concentration of nutrients over a longer period of time. Fast-release fertilizers do the opposite.
- On heavy (clay) or compacted soils, fast release fertilizers are better than slow-release fertilizers. The longer a fertilizer granule remains undissolved, the greater the chances of it being washed into waterways. On sandy soils, however, nitrogen can leach through the soil into the groundwater. On these soils, slow release nitrogen is preferred. Slow release nitrogen sources provide soluble nitrogen over a period of time so there is not a large concentration of nitrogen available for leaching.
- Fertilize in the autumn, never in spring. Spring applications can actually harm lawns by promoting more top (leaf) growth than root growth. Shallow root systems are unable to sustain lawns through a drought or a harsh winter. Fall fertilizer applications, however, promote deep, healthy root systems and hardy lawns.
- Fall fertilizer applications should be made when the average daily temperature drops to 50°F.
- When careless fertilization is followed by routine removal of grass clippings (a natural source of nitrogen) further fertilization is required. The cycle of fertilizing, rapid growth, more cutting and bagging, more fertilizing, etc. gets to be time consuming and costly. It also increases the chance that fertilizer will be washed off to lakes and streams.
- Test the soil. Before planting a garden or fertilizing your lawn, have the soil tested. A soil test takes the guesswork out of fertilization.
- Fertilize lawns in the fall. Fall fertilization promotes healthy lawns with deep roots.
- Healthy trees and shrubs do not require an annual fertilizer application. Overfertilized shrubs, in fact, will produce more growth and require more pruning.
- Sweep all fertilizers, soil, and vegetation off paved surfaces.
- Fertilizers, soil particles, grass clippings and leaves contain nitrogen and phosphorus, which can cause nuisance algae growth if washed through storm sewers into nearby water-ways. In addition, decomposing leaves and grass clippings can rob streams and lakes of oxygen.
- Contact your county UW-Extension office. Soil testing information and fertilizer recommendations for lawns and gardens, and suggestions for selecting the right plants, are available at your county UW-Extension office.
- More information:
- Pesticides and fertilizers should not be mixed.
- Using weed killers at the wrong time of year or spraying with insecticides "just to be on the safe side" is wasteful and environmentally damaging.
- Read all directions and warnings on the product labels. Pesticides should be a last resort. Using such chemicals without proper diagnosis of the problem and careful application is similar to a doctor prescribing medicine with potentially serious side effects for a condition that proper diet and moderate exercise could cure. Resist the urge for a quick chemical solution.
- Because yard care chemicals are readily available and easy to apply, there is a danger that their results is underestimated, especially if previous use resulted in no adverse incident. Although it's tempting to skip the instructions and just "get the job done," pesticide application is not the time to overlook something so important. The suffix "-icide" means "to kill." Insecticides kill insects, herbicides kill plants and fungicides kill fungus species. While greater success is realized every year developing chemical and application methods that are more target-specific, the fact remains that pesticides sometimes kill living things other than their targets.
- If beneficial predators (such as birds) are poisoned along with pests, then natural controls are gone, allowing pests to multiply more rapidly. This may further the need for more chemicals and set in motion an unfortunate and unintended cycle. Thus the yard can get "hooked" on a pesticide.
- When used in heavier-than-recommended concentrations, nearly all yard care chemicals can pose an environmental problem. This not only wastes money, but puts the applicator, family, neighbors, beneficial plants and animals, and downstream waters at risk. Many recommended label rates are already liberal, designed so that products still work under less than optimal conditions.
- Even under-application can create problems. If label directions are misread or pesticides are being "sprayed about" in diluted amounts just to use up existing supplies, then chemicals will not be effective and needlessly enter the environment. Also, pest populations subjected to non-lethal doses may begin to genetically develop resistance to the chemicals designed to kill them.
- Clean up any spilled chemicals. Chemicals spilled on pavement during chemical mixing and loading can quickly be washed away with the next rain to pollute lakes and streams. If not cleaned up, a sometimes-severe health threat may also persist. Fortunately, an impermeable surface can contain some spills and allow time for clean-up.
- Limit the use of toxic or hazardous products in general. Keep them away from storm sewers, lakes, and streams.
- More information