by Jeff Schloss, Extension Professor and Water Resources Specialist, University of New Hampshire

There is often controversy and confusion regarding lawns on shoreland properties.  Some consider lawns inconsistent with the natural shoreland ecology while others want to bring to their shoreland home the same look and feel as the neighborhoods in surburbia that they have grown up with. 

As all vegetation provides at least some water quality functions, a lawn managed in the proper way can still allow for stabilized soils, filtered water infiltration into the ground and some nutrient and pollutant capture.  And, as with all vegetation, lawns sequester carbon dioxide, produce oxygen and, by doing so, cool the planet.  Thus, lawns still make a better alternative to pavement or patios which create greater runoff conditions and impede groundwater recharge. 

Of course, managed improperly, lawns and their care can add to pollutant and nutrient loading to our surface and ground waters, attract nuisance weed plants and insect pests (and even big pests like Canadian Geese!), impact important plant and wildlife species, as well as greatly reduce the available drinkable water supply with their potential need for irrigation.  So, how might you maintain a lawn area to enjoy on your shoreland property (or any property for that matter) while minimizing your impacts to the water quality and natural ecology?

The recent publication, “Landscaping at the Waters Edge: An ecological approach” from UNH Cooperative Extension (extension.unh.edu/resources/) covers the importance of considering how you may landscape your shoreline property for the improvement of water quality as you also enhance the enjoyment and value of your property.  While the publication goes into much greater and more specific detail, the information below is a good start when considering lawns and their potential impacts to water quality.

Everything in moderation.  We often hear from our health providers that moderation is the key to healthy living and the same holds true for natural systems.  Questions to ask yourself here include: How much lawn or open space do we really need for our intended uses?  Do we need to have our open space all as a monoculture of a single type of grass or can we live with a combination of grasses and groundcovers that match our use?  There are many varieties of grasses depending on the type and frequency of use (i.e.; occasionally picnicking to kids playing ball everyday) and site conditions (soils, sun exposure and slope).  Recently developed fescue grasses, for example, require less maintenance (water, mowing and fertilizing) and can even be obtained with symbiotic bacteria in their roots that make the grass better resistant to pests and diseases.  The best approach is a mix of grass species with other groundcovers and white clover (or another low growing legume to naturally supply nitrogen to the soil).  Talk to your county extension educator, landscaper, or garden center expert about your options.

Location, location, location. Yes, the mantra of real estate agents also works well for lawns.  Since a lawn requires additional maintenance that even, when not excessive, can still threaten water quality, locating the lawn as far away from the shore as you possibly can and maintaining a significant buffer area downslope from the lawn with a mix of shrubs and woody plants to make up for this.  A lawn leading right down to the water is the worst thing for the water and it will attract nuisance geese.  It’s a known fact that keeping the vegetation high at the waters edge will discourage geese from coming onto a property.  It also provides many water quality and wildlife related benefits.

Test first, apply later.  It is most important to test your soil before even thinking about applying fertilizers.  Once grass is established, fertilizing more than once a year (unless the yearly dosage is applied in fractions) is generally excessive and can lead to excess nitrogen loading to surface and groundwaters. Lawns tend to need less acidic soils, so sometimes just applying crushed limestone to reduce the acidity can release enough nutrients that were bound to the soil to maintain the lawn.  A soil test will let you know exactly what you need to maintain a healthy lawn.  As will often be the case if the test informs you that only nitrogen is needed, look for low to no phosphorus fertilizer blends (middle number of the N-P-K rating on the bag should be “0”) since phosphorous causes algae blooms in lakes.  Generally, a well-established lawn can survive adequately with no more than one to two pounds of nitrogen per 1000 square feet.  The best time to apply fertilizer on an established lawn is around mid-September when the grass is still active enough to incorporate the fertilizer into the plants, the summer drought is over and the surrounding vegetation is well established to capture any runoff from your lawn.  Choose slow release fertilizers only, to ensure less polluted runoff.  Many folks apply crushed limestone in the spring and fertilize in the fall.  Some folks have never felt the need to fertilize and others have had their best results just using lake water (which usually contains small amounts of nutrients) for irrigation.  It is really up to you to balance the results you are looking for with the minimum applications needed.  Remember, the NH Comprehensive Shoreland Protection Act prohibits applying anything except limestone in areas within 25 feet of the high water line except in some circumstances.

Read the fine print! A recent survey in Maine indicated that many consumers did not realize that “Weed & Feed” products contain both fertilizers and pesticides.  Why pay for and put down something that can potentially threaten the health of pets and children and water quality when you may not need it in the first place?  If you do have weed or insect problems, consult with your county extension educator, landscaper or garden center expert to learn of safer alternative controls.  No matter what you choose to use, always read the application directions and never over-apply.  Many of the plants and animals that form the foundation of the aquatic food web are extremely sensitive to pesticides.

Conserve every drop.  If you are on a public water supply, it is best to choose grass species with low watering requirements or use alternative irrigation supplies like rain barrels or cisterns or even the water directly from the shore.  Summer water demand for lawns can be very significant.  Depending on the species and soil conditions, you should water only when needed, no more than a half inch to an inch total weekly.  You can use a rain gauge or a can to measure rainfall and irrigation amounts.  Early morning watering is preferable to minimize evaporation loss but give the water enough time to infiltrate and to allow the leaf blades to completely dry before night to not encourage disease problems.  Keeping the lawn height at least three inches or higher will also encourage deeper roots which require less water (and a mulching mower blade will allow for those grass clippings to recycle nutrients back into the soil).  Remember that in times of drought and hot summer, lawns are supposed to go dormant.  Letting this happen is the most environmentally friendly thing you can do.

So, the choices are yours—you can have an open space on your property with minimum impact to our waters if you can restrict its size, locate it properly, provide adequate vegetative buffer areas down-slope and use low input design and maintenance methods.

For more information:
Contact Jeff Schloss at jeff.schloss@unh.edu.