Lawn Care Near Lakes: Why Should I Be Concerned?

Many people find landscaping and gardening to be important parts of a healthy lifestyle. These activities can also improve both the beauty and value of your property.  However, misuse of fertilizers and chemicals threatens the water quality of your lake. For lakeshore property owners, the value of your property is directly linked to the water quality of your lake. Should that lake develop an algal bloom, your property value will drop significantly.  

This section of Lake*A*Syst will help you evaluate whether your lawn care practices have the potential to increase the phosphorus level of the lake on which you live. 

Natural Buffers or Lawns?

A well-groomed, lush, green lawn is not the ideal landscape for lake shorefronts. A natural buffer of trees, shrubs, groundcovers and duff is the preferred planting. The grass in a lawn does not prevent most storm water runoff from reaching the lake. And a lawn can be more prone to soil erosion than a naturally vegetated buffer. The duff layer (made of leaf matter, sticks and plant litter) tends to absorb water more effectively than home lawns. Buffers require considerably less effort to maintain than lawns, and are ideal for people using their lake home only part of a summer season. Please see the section of Lake*A*Syst on Landscape and Vegetated Buffers to learn more.

If You Must Have A Lawn…

If a lawn is important to you, there are several things that you can do to make it less of a threat to lake water quality.

• Use only phosphorus-free fertilizer materials.
• Maintain appropriate soil pH.
• Proper turf variety selection.
• Proper turf maintenance.
• Include a vegetated buffer between your lawn and the lake.

Phosphorus and Lake Water Quality

Phosphorus (P) is the nutrient that limits growth of algae in lakes. Maine lakes are not well buffered with chemicals that tie up P which makes them very sensitive to any additional P, even in extremely small amounts. In fact, lake algal growth can be stimulated with only 15 parts per billion of P. Of all the potential sources of P entering a lake, the home lawn can be quite an important source.  

Phosphorus-Free Fertilizers

You may think that one lawn won’t make a difference, but it can. If you make the change to stop using phosphorus (P) based fertilizers encourage your neighbors and others to do the same. Awareness and education can have long term benefits to preserve your lake water quality. Many hardware stores have begun handling P-free fertilizers. 

By purchasing only P-free fertilizers to use in lawns and gardens near the lake, you can make great strides to preserve water quality. You may wonder why you don’t need to add Phosphorus (P) to lawns and gardens. The reason is that most Maine soils are naturally high in P. Plants will not grow well in the absence of P because it is required by plants for seed production, energy compounds, and many other important plant reactions. But, plants generally only respond to P if soil test P levels are low or soil pH is very low. Exceptions include blueberries and rhododendron plants, which grow best in acid soils.

The best way to find out if any nutrient additions are needed to grow turf on your soil is to take a soil test. Soil test kits are available through your University of Maine Cooperative Extension county office or online at Analytical Laboratory and Maine Soil Testing Service. Once you know the natural phosphorus and pH levels in your soils, you can make educated adjustments. Keep the soil pH between 6 and 7 to make the natural phosphorus in your soils available to the plants.

Turf Variety Selection

Choosing the right variety of grass is the first important step in creating a great lawn. Annual grass only lives for one year so choose seed with a high percentage of perennial grass seed. Evaluate the amount of shade and soil type where the lawn is going to be planted.  Plant some clover or other legume in the grass blend. Legumes fix nitrogen from the atmosphere, which will help make your lawn lush.  Even if you don’t plant them, legumes will find their way into your lawn.

Grass Clippings

At one time, grass clippings accounted for 20-50% of the solid wastes entering landfills. In an attempt to reduce this volume of recyclable waste entering mainstream landfills, some states have passed legislation to prevent grass clippings and other yard materials from entering our landfills. People across the US are realizing that after mowing it is better to leave the grass in place to decompose. Follow the mowing recommendations above and then leave the grass clippings to benefit your lawn. If you wait to cut the lawn when the grass is a foot tall the clippings will be too large and might suffocate the lawn. Grass clippings are a natural way to fertilize your lawn. As worms and microorganisms break down the grass clippings, nitrogen and other essential plant nutrients will be slowly released and become available to the plants. Basically this puts a 4-1-3 fertilizer on your lawn each time you mow. Brush clippings off of impervious surfaces to prevent them from being carried away by stormwater runoff. If you do decide to rake your lawn consider composting the clippings. A compost pile is a great way to turn vegetation into nutrient rich soil.  Locate the compost pile at least 20 feet away from the lake. Ensure that there is a vegetated buffer between the compost pile and the lake to prevent nutrient rich soil from reaching the lake. For more information on composting, visit the Maine Compost School.

Water Usage

Proper watering can prevent leaching of fertilizers and pesticides, reduce soil erosion into the lake and provide stronger plants. Use the correct variety of turf grass for the conditions that occur on your lawn. If the area is prone to drying, plant a drought-resistant variety of grass. If you chose to water your lawn you should know how much water you are adding. If water begins to runoff instead of soaking in, turn off the sprinkler.  If the lawn still needs water turn it back on after the excess water has soaked into the ground. Most hose sprinklers apply ¼ to ½ inch of water per hour. You can get a more accurate number by creating a watering gauge.  Put centimeter or inch marks on several containers and place them under the sprinkler. Water early in the morning to prevent the water from evaporating in the noon day sun and to keep the grass blades from scorching under the water and sun.

Turf Pests

Pesticides are chemicals used to control insects, weeds, or diseases in turf and ornamental crops. Fortunately, insect damage to turf is not particularly common in Maine. Sometimes chinch bugs and white grubs can be problematic. It is important to identify these insects before making a decision to treat. A healthy lawn is more resistant to insect infestations. Be sure you know what pest is causing the damage before using a pesticide.  Contact your University of Maine Cooperative Extension county office for more information. If it is a challenge to identify the insect, you can try the UMaine Cooperative Extension Pest Management Office at (207) 581-3880 or 491 College Avenue, Orono, Maine 04473.

Whereas insects are only occasionally problematic, weeds are usually always present in lawns. However, many people don’t mind a few weeds and consider the lawn more interesting with many types of plants growing. If you utilize good lawn management methods (2½” cutting height, decent fertility, and varietal selection) you can stay ahead of the weeds. Remember that weeds provide some prevention for soil erosion, which is necessary for long term lake health. If you must use something to control weeds, please read the label. The label describes the appropriate uses, and will outline the proper clothing to wear when applying the material. Keep all these materials out of the reach of children and pets. Remember that most lawn herbicides can leach or runoff into the lake during rain events. Purchase only what is required to treat the lawn area using as little material as possible. Lastly, keep in mind that most weed and feed fertilizer blends will contain phosphorus (P). The use of P-based fertilizers on the lakeshore is not considered a best management practice in protecting lake water quality.

Take the Lawn Care Self-Assessment.

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