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Environmentally-Friendly Lawns
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Environmentally Friendly Lawn
Grow an environmentally friendly lawn
A health lawn contributes to a healthy Chesapeake Bay.

By Gregg Robertson, PLNA Government Relations

Lawns are a significant component of the residential landscape, and are important to homeowners for many uses.  In fact, recent estimates indicate that lawns and turf grass is now the largest "crop” in the Chesapeake Bay watershed, covering more than 3.8 million acres and eclipsing pasture, hay/alfalfa and row crops like corn, soybean and wheat. By properly managing this resource, we can significantly improve water quality in the Bay.

A recent report by the Chesapeake Bay Program of EPA compiled much of the research about lawns and their contribution to pollution in stormwater runoff. Their overall conclusion is that maintaining a dense, vegetative cover of turf grass reduces runoff, prevents erosion and retains nutrients in the turf grass (see "Expert Panel Report” below).

In other words, if you have a lawn, keeping a cover of dense, healthy turf grass is essential to reducing the pollution getting into the Chesapeake. On the other hand, a thin, sickly lawn will contribute to Bay pollution.

The Expert Panel Report goes on to say that:

The research demonstrates that dense vegetative cover helps to reduce surface runoff which can be responsible for significant nutrient export from the lawn, regardless of whether it is fertilized or not. Dense cover has been shown to reduce surface runoff volumes in a wide range of geographic settings and soil conditions.

If a lawn does not have a dense cover, it has an elevated risk for nutrient export, especially if soils are compacted or slopes are steep. In these situations, the primary nutrient management practice is to identify the factors responsible for the poor turf cover, and implement practices to improve it (e.g., tilling, soil amendments, fertilization or conservation landscaping).

For a full copy of the Expert Panel Report follow this link:

As the EPA Expert Panel Report concluded, a healthy lawn contributes to a healthy Bay, but lawns also play a useful role in landscape design and your backyard ecology if incorporated into your landscape plan with sensitive attention to plant selection and wildlife needs. Your yard doesn't have to all meadow or woodland to play a useful role in your neighborhood's ecological system. Besides, without a lawn, where would you play volleyball or croquet?

Here are the EPA Expert Panel’s recommendations for growing and maintaining an Bay-friendly lawn:

Lawn Care Practice 1. Consult with the local extension service office, certified plan writer or applicator to get technical assistance to develop an effective urban nutrient management plan for the property, based on a soil test analysis.

The precise lawn care prescription should be based on site-specific recommendations that take into account soil properties, the type of grass species, the age of the lawn, and other factors. Professional expertise is essential to develop an effective plan.  Look for professionals who are Pennsylvania Certified Horticulturists or Landscape Industry Certified to help you analyze your lawn’s specific needs.

Lawn Care Practice 2. Maintain a dense vegetative cover of turf grass to reduce runoff, prevent erosion, and retain nutrients.

The research demonstrates that dense vegetative cover helps to reduce surface runoff which can be responsible for significant pollution from the lawn, regardless of whether it is fertilized or not. Dense turf grass cover has been shown to reduce surface runoff volumes in a wide range of geographic settings and soil conditions.  If your lawn does not have a dense turf grass cover, it has an bigger risk for nutrient runoff, especially if soils are compacted or slopes are steep. In these situations, the primary nutrient management practice is to identify the factors responsible for the poor turf cover, and implement practices to improve it (e.g., tilling, soil amendments, fertilization or conservation landscaping).  By maintaining a healthy, dense lawn you are contributing to improved water quality in the Bay.

Lawn Care Practice 3. Per the plan developed by your local extension agent or your lawn care professional, choose not to fertilize, or adopt a reduce rate/monitor strategy, or apply less than a pound of nitrogen per 1000 square feet per each individual application. 

Some lawns, due to their age or natural soil fertility may be able to maintain a healthy, dense cover without additional fertilization. However, if your lawn is thin, is weed infested or has bare spots, you should consider fertilizing to restore a thick turf grass cover.  Penn State Extension recommends that an average lawn requires from 3.0 to 3.5 pounds per 1,000 square feet of nitrogen per season for optimal health and growth. Your specific lawn may require slightly more or less depending upon its condition and how hard it is used.

Most bagged lawn fertilizers (Scotts, Vigoro, etc.) that you will find in independent garden centers or big box stores in Pennsylvania will apply nitrogen fertilizer at rate of between 0.8 to 0.9 pounds per 1,000 square feet if you set your spreader to the setting recommended on the bag. It’s important to follow the bag directions and spreader settings a closely as possible. To achieve the range of nitrogen application recommended by Penn State, you will need to do three to four applications of fertilizer per season spread throughout the season. : early spring, late spring, late summer and mid-fall.

Most bagged fertilizers will have the recommended application rate on the bag, for example, 2.5 pounds per 1,000 square feet. This will be the total amount of product that is applied. To find out the application rate for nitrogen, look at the analysis on the bag, generally expressed as three numbers: 32-0-2, for example. These numbers stand for the percentage of nitrogen, phosphorus and potash in the bag. Multiply the first number (the nitrogen percentage) expressed as a decimal or .32 by the application rate of 2.5 lbs. per 1,000 sq. ft. and you will get the application rate for nitrogen or 0.8 lbs. per 1,000 sq. ft., assuming you follow the bag directions and spreader settings.

You may want to experiment and see if you can maintain a dense healthy covering of turf grass with fewer applications of fertilizer. Monitor your lawn and if fewer applications in a season results in thinning of the turf and weed invasion, go back to the levels recommended by Penn State Extension. Most professional lawn care companies will do four to five applications of nitrogen fertilizer throughout the season to supply the seasonal nitrogen needs of a lawn.

Most bagged fertilizers in Pennsylvania have already removed phosphorus from their products that are available to the public, except for "starter fertilizers” used for starting grass seed in new lawns. If your soil tests show a phosphorus deficiency, ask your lawn care professional for recommendations on how to provide the phosphorus your lawn needs.

Lawn Care Practice 4. Retain clippings and mulched leaves on the lawn and keep them out of streets and storm drains. 

Use a mulching mower to return grass clippings and leaves to your lawn. Lawn clippings are an important nutrient source for lawns, as well as an important source of organic matter which enhances stormwater infiltration, soil health and water retention. Studies have shown that lawn clippings quickly decompose and return nutrients to the soil within a matter of weeks. Nitrogen fertilization could be reduced without decreasing turf grass quality when clippings are returned to the lawn by using a mulching mower. 

Lawn clippings are high in nutrients and should be treated as if they were a fertilizer. You should keep lawn clippings and leaves on your lawn, and out of the gutter, street or storm drain system, regardless of whether you fertilize or not. In addition, the amount of nutrients supplied by lawn clippings and mulched leaves should be accounted for when assessing fertilizer needs. 

Lawn Care Practice 5. Do not apply fertilizers before spring green up or after the grass becomes dormant.

Research has shown a clear link between lawn nutrient runoff and the timing of fertilization. The risk of pollution by leaching or surface runoff is greatest during the seasons of the year when the grass is dormant. The start of the dormancy period is dependent on the climatic zone in the Bay watershed. In the northern part of the watershed, it may begin around Halloween, whereas dormancy begins around Thanksgiving in the southern part of the watershed. Fertilizer applied to cool season grasses during the winter or late fall is highly susceptible to creating pollution.

Lawn Care Practice 6. Maximize use of slow release N fertilizer. The risk of nutrient export is reduced when slow release fertilizer products are used during the growing season, compared to water soluble formulations. Slow release fertilizer is typically shown on fertilizer products as water insoluble nitrogen or WIN, and can range from 20 to 50% of the total nitrogen product. You can shop for the fertilizer product with the greatest percentage of WIN. Slow release fertilizer formulations should be avoided in the late fall, as they are likely to be releasing nitrogen when the grass is dormant or frozen.

Lawn Care Practice 7. Set Mower height at 3 inches or taller.

Maintaining taller grass produces a deeper and more extensive root system, which in turn, increases nutrient uptake and reduces lawn runoff volume. The deeper roots also reduce the need for supplemental irrigation during times of drought, suppress weeds and increase turf density. Maintaining taller grass on your lawn has been produces less nitrogen and phosphorus runoff. 

Lawn Care Practice 8. Immediately sweep off any fertilizer that lands on a paved surface.

Rotary spreaders are the most common method to apply fertilizers and can broadcast fertilizer granules near the edge of the lawn, street or driveway, where they can be subsequently washed off in a rain storm.  Sweep wayward granules up before they have a chance to get into gutters and storm sewers. If you use a rotary spreader, purchase one with a deflector shield to prevent spraying fertilizer on the street, driveway or sidewalks. 

Lawn Care Practice 9. Do not apply fertilizer within 15 to 20 feet of a stream, pond or other water body and consider managing this zone as a perennial planting, meadow, grass buffer or forest buffer.

The risk of runoff is greatest from lawn areas adjacent to water features such as streams, shorelines, sinkholes and drainage ditches, simply due to the short distance for nutrients to travel via leaching and/or surface runoff. Consider establishing a riparian buffer of shrubs, trees or perennials along streams and other water courses.

Lawn Care Practice 10. Employ lawn practices to increase soil porosity and infiltration capability, especially along portions of the lawn that are used to convey or treat stormwater runoff.

A well maintained lawn, with a dense healthy cover of turf grass can significantly slow and absorb storm water runoff.  However, you should consider installing other stormwater best management practices where runoff is especially problematic. Rain gardens, rain barrels, bioswales and the like can help absorb stormwater that the lawn alone cannot.

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