Lawns are a significant feature in the urban and suburban landscape. This large area of managed landscape has the potential to contribute to urban runoff pollution due to over-fertilization, over-watering, over-application of pesticides and herbicides, and direct disposal of lawn clippings, leaves, and trimmings. Erosion from bare patches of poorly managed lawns contributes sediment to waterways, and disposal of lawn clippings in landfills can reduce the capacity of these facilities to handle other types of waste.
There are eight steps for maintaining a healthy, attractive lawn with less maintenance and fewer chemical inputs.
Step 1 Lawn Conversion
Grasses are very water-hungry and labor-intensive landscaping plants when compared to ground covers, flowers, shrubs, and trees. To reduce the maintenance requirements of a lawn and address problem areas where turf is difficult to grow, property owners can identify areas where turf grass can be replaced with other types of plantings. These areas may include lawn edges, frost pockets, exposed areas, dense shade, steep slopes, and wet areas. Choose vegetation that is suited to the local conditions. New England Wildflower Society’s 2005 Plant Catalog contains detailed descriptions of hundreds of native plants as well as list of species appropriate for specific environmental conditions. The catalog is available online at http://www.newfs.org/nurscat05/.
Step 2 Soil Building
Lawn owners should analyze their soil every one to three years to determine its suitability for supporting a lawn and to identify whether additives are needed or adjustments should be made to optimize growing conditions. Soil characteristics that should be measured include pH, fertility, compaction, texture, and earthworm content. Soil test kits (for pH and fertility) can be purchased inexpensively at a garden center or samples can be analyzed for a small fee at UMass Extension in Amherst. More information about UMass’s soil testing services can be found at http://www.umass.edu/plsoils/soiltest/.
Soil amendments should be added based on the results of your soil test. Prior to planting, sandy and heavy clay soils may be amended by adding organic compost to improve aeration and nutrient-holding capacity. Compacted soil under an established lawn should be aerated to improve the flow of water, air, and nutrients to the root zone. Aeration is a non-chemical technique that relieves compaction, increases rooting, helps prevent thatch accumulation, incorporates organic matter into the soil surface, and helps prevent damage by insects and disease. While the presence of earthworms is an indicator of healthy soil, the presence of white, healthy roots is the ultimate goal. Rooting can be checked by cutting a four-inch deep slice of plug or turf and soil. Roots should be at least four inches deep and the tips should be white. Poor root condition may be the result of compacted soils, ineffective watering practices, and poor fertilization.
Step 3 Grass Selection
Grass seed is available in a wide range of cultivated varieties, so care must be taken to choose the type that grows well in your climate, matches site conditions, and is consistent with the property owner’s desired level of maintenance. There are four major types of lawn grasses:
Kentucky Bluegrasses (Poa pratensis)
This is a popular lawn grass in New Jersey. It is hardy, attractive, widely adapted and known for its pleasing color and leaf texture. New varieties have some shade tolerance and improved disease resistance. It is suitable for moderately to well-drained soil but is somewhat slow to establish from seed. Spreading underground rhizomes (stems) enhance recovery from injury and fill in voids. Seeding rate is approximately two pounds per 1,000 square feet. Fall seeding is preferred, as spring seedlings are difficult to establish.
Tall Fescues (Festuca arundinacea)
This is a coarser bunch-type grass able to persist in moderate to well-drained, infertile soils. Newer varieties are improved in leaf color, texture, and density. Tall fescues are also known for rapid establishment from seed, excellent drought tolerance and ability to tolerate traffic. Seeding rates are four to six pounds per 1,000 square feet.
Fine Fescues (Festuca spp.)
Fine fescues are comprised of several species (hard, sheeps, creeping red). As a group, they are known for their ability to persist in shady areas as well as in dry infertile locations. They establish slightly faster than Kentucky bluegrass. Improved newer varieties are useful for lower maintenance turfgrass areas. Fine fescues do not tolerate high traffic. Seeding rates are four to six pounds per 1,000 square feet.
Perennial Ryegrass (Lolium perenne)
Breeding advances have produced varieties markedly improved over the older non-persistent types. These newer turf type ryegrasses have excellent color and fine textured leaves. They survive in a wide range of soil conditions, but grow poorly in extremely wet areas. They possess moderate shade tolerance and very rapid establishment. Seeding rates are four to six pounds per 1,000 square feet.
Step 4 Mowing and Thatch Management
Each turf grass variety has an ideal mowing height range. Kentucky bluegrass, fescues, and ryegrass prefer a mowing height of three inches. Turf grasses use water more efficiently and out-compete weeds better when kept at the higher end of their mowing range. Mowing grass too short decreases rooting and increases the need for frequent watering. Tall turf competes more vigorously against weeds and can usually tolerate more insect and disease pressure. Grass grows at different rates throughout the season. Therefore, grass should be mowed only as needed. If excessive thatch (which can prevent water and nutrients from reaching the roots) has developed, the lawn should be dethatched by raking or with an automated dethatcher. A thatch layer less than one-half inch can be beneficial by providing insulation and increasing the turf’s resiliency.
Step 5 Minimal Fertilization
Based on the results of the soil test described above, a lawn might require nutrients to promote or maintain healthy growth. Nutrients can be partly supplied by leaving a moderate amount of fine grass clippings on the lawn after mowing. These clippings can provide nearly half the required nutrients to the lawn and they hold in moisture, speed decomposition and relieve the burden of landfills to handle excessive yard waste. Additional fertilizers can be supplied with compost or commercial fertilizers that are of an organic encapsulated nitrogen type (slow-release), but they should be applied at or below the rates prescribed on the packaging. Compost or organic and encapsulated nitrogen fertilizers reduce the risk of nutrient leaching and have been shown to release nutrients more gradually. Slow-release fertilizers are also beneficial for reducing nitrogen losses from soils that are prone to leaching. Organic products offer the additional benefits of increasing soil condition and promoting the growth of desirable soil organisms. For more information, Rutgers University Cooperative Extension publishes fact sheets such as “How to Calculate the Amount of Fertilizer Needed for Your Lawn” and “Best Management Practices for Home Lawns” at http://www.rcre.rutgers.edu/garden/.
Step 6 Weed Control and Tolerance
A property owner must decide how many weeds can be tolerated before action is taken to eradicate them. A few weeds will not substantially interrupt the continuity of the turf. The best way to keep weeds at bay is to maintain a healthy, dense lawn that shades the ground surface, preventing weed seedlings from taking root. However, if weeds do take hold, they should be dug or pulled out. Chemical herbicides should only be used to spot treat persistent weeds, not applied universally.
Step 7 Pest Management
Effective pest management begins with maintenance of a healthy, vigorous lawn that is naturally disease-resistant. Integrated pest management (IPM) is an effective and environmentally sensitive approach that relies on a combination of common-sense practices. IPM is not a single pest control method but a series of pest management evaluations, decisions, and controls. IPM is a sustainable approach to managing pests by combining biological, cultural, physical and chemical tools. Biological controls involve the use of natural enemies to manage pests. Cultural practices include mowing, fertilization, irrigation, aeration, dethatching, and rolling. Chemical controls involve the use of pesticides.
Chemical controls are highly effective but may result in damage to or death of desirable species, such as bees. If strong chemical pesticides are applied incorrectly, they can contaminate receiving waters. Several less toxic pesticide alternatives area available to prevent infestation or halt current infestations. Biopesticides, for example, are used to control pests without the use of poison. Biopesticides can be biochemical, such as garlic and pheromones, or microbial, such as bacteria, fungi, and viruses. The Biopesticides and Pollution Prevention Division in EPA’s Office of Pesticides Programs promotes the use of biopesticides as components of IPM programs. The Biopesticides website is http://www.epa.gov/pesticides/biopesticides.
Step 8 Sensible Irrigation
Underwatering fails to provide water below a few inches of soil, causing grasses to be fragile and shallow rooted. Overwatering promotes excessive growth and humid disease prone conditions that can damage the lawn. Overwatering can also result in runoff and leaching of nutrients. It is best to water deeply, but not too often. Deep watering encourages the grass to grow deep roots, whereas shallow watering maintains shallow roots and reduces the lawns ability to retain moisture during dry periods. The lawn should be watered only when needed and sprinklers should be carefully calibrated to wet the soil to a depth of six inches without causing runoff. Watering should be done in the early morning to prevent excessive evaporation. Determining and controlling the rate, amount, and timing of watering will reduce soil erosion, runoff and fertilizer and pesticide movement. An irrigation system should be designed to have an average application rate that is less than the infiltration capacity of the soil to avoid surface ponding and to maximize water percolation. Trickle and drip irrigation systems can save water by more directly irrigating the roots, resulting in less evaporation than overhead sprinklers.
Other Resources:
USDA’s Natural Resources Conservation Service website “Backyard Conservation” presents technical information and management practices to increase food and shelter for birds and other wildlife, control soil erosion, reduce sediment in waterways, conserve water, and improve water quality, inspire a stewardship ethic, and beautify the landscape. http://www.nrcs.usda.gov/feature/backyard/
