In terms of acreage devoted to production, grass in the United States covers more than 40 million acres — as much as corn, wheat, soybeans and the next five top irrigated crops combined. Although in most cases, it has only aesthetic value, every year Americans devote much of their leisure time and discretionary income to the maintenance of their lawns.
A variety of management practices collectively make a huge impact not only on the health of each lawn but on the environment in general. Armed with a bit of knowledge, the homeowner can adjust his or her cultural practices in such a way as to decrease time and expense given to raising grass and become more eco-friendly at the same time.
Mowing, watering, fertilization and weed, disease and pest control, are the main cultural practices in which humans indulge in pursuit of the perfect lawn. The chemical treatments associated with the latter have the most potential to do harm.
Synthetic chemicals in general do indiscriminant harm to the microbiological life in the soil, as well as to soil macro-organisms, beneficial insects and wildlife overall. Such chemicals also commonly become contaminants in surface and groundwater.
Application of chemicals to the lawn in general is done with the intent of eliminating or killing unwanted pests or weeds, at the same time as feeding the grass. If the focus is shifted instead to building a healthy foundation of underlying soil, teeming with beneficial fungi and micro- and macro-organisms, the objectives of a weed and pest-free healthy lawn can be achieved as easily and often more cheaply, while leaving less of an ecological footprint.
Lawn Planning & Design
Achieving the objective of a healthy lawn begins with landscape planning and thoughtful design. Proper contouring can gently channel runoff or give it time to soak in, thereby preventing erosion, or directing it to trees, shrubs or perennial gardens. Loam with good drainage and at least 3 to 5 percent organic matter should be laid down at a minimum depth of 6 inches, with 12 to18 inches being the ideal.
Careful placement of landscape plants can prevent excessively shady areas which could lead to encroachment by mosses or development of fungal diseases. Water harvested from roofs can be collected for use on the lawn or directed to a rainwater garden. Such design aspects both reduce demand for water while minimizing water that re-enters streams and lakes with potential pollutants.
Lawn Grass Species Selection
The next step in creating a new lawn is choice of species of grass. You will have already measured the area and adjusted pH with the appropriate amount of lime to raise or sulfur to lower. Grass likes a slightly acidic pH (about 6.5). Proper pH optimizes availability of nutrients to the plants as well as encourages proliferation of beneficial microorganisms.
Fall is the ideal time to seed for best root development. The choices among cool season varieties are compact, turf-type tall fescues, and fine-leafed types such as blue grasses, fine fescues and perennial ryes. Tall fescues are wear-tolerant, disease-resistant and can be mowed 3 to 4 inches tall.
Fine fescues are more prone to disease but are popular because they are softer to the touch and more aesthetically pleasing. The most common northern varieties used are Kentucky Bluegrass, Perennial Rye, Fairway Wheat, and Chewings, Hard, Red and Tall fescues. Of these, Chewings tolerates shade well, while turf-type Tall fescue is best in full sun. In the south, the common choices are Bahia, Bermuda, Centipede, St. Augustine, Seashore, Carpet grass and Zoysia. Preference should be given toward species which are indigenous and thus better adapted to your particular environment. Your local cooperative extension can help with recommendations.
It is also recommended that you avoid a monoculture by using a mix of varieties which match your specific soil and light conditions. A biodiverse lawn is better at resisting disease and pests. Look to see that the mix includes an endophytic fungus, which is beneficial in spite of the fact that it lives inside the plant. The fungus makes the plant taste bad to insect pests, thus protecting it naturally. Natural toxins provided by the fungus also provide disease protection. One disadvantage, however, is that animals grazing on grass with this fungus may experience adverse reactions.
In addition to a diverse mix of seed, it is advantageous for your mix to include clover, especially white clover, which fixes nitrogen in the soil. Five percent is the ideal proportion which Paul Tukey recommends in The Organic Lawn Care Manual. This can produce half of the nitrogen requirements of your lawn, he says, and leaving clippings after mowing would supply supply the remainder. Make sure the seed you buy is weed-free and has a germination date of less than one year.
Natural Lawn Care: Mindful Mowing
In an existing landscape, the single most important effective step one can take in creating a healthy lawn is to adopt proper mowing practices. Both public and private research has shown that this alone can control as much as 80 percent of potential weed problems.
The first rule is to mow high. The proper mowing height depends on the variety of grass, but for most it is 3 inches. Secondly, one should never remove more than one-third of the height of the grass blade. Longer grass blades are stronger, by virtue of having more surface area to photosynthesize, and help shade or crowd out weeds while better preventing the underlying soil from drying. Taller grass will also develop deeper roots, thus giving more drought resistance and less need for fertilizer. Also, resist the urge to mow more frequently than is necessary, especially in shady areas where grass must maximize its photosynthetic ability.
The mower blade should be kept sharp, such that it makes a cleaner cut rather than tearing the grass. Tearing makes the grass more susceptible to infection and disease. Torn grass tips turn brown, causing a brown cast to the lawn. Sharpening should be done once or twice during the season depending on area, or after every eight hours of mowing.
A sharp mower blade can reduce fuel consumption by as much as 25 percent. A spare blade can be changed out quickly so that the job can be completed while the dull blade is being serviced. It is good practice also to hose down the underside of the mower after each use for cleaner cutting and more efficient mulching. Do not mow when the grass is wet. Finally, mow in the evening or the cool part of the day, and choose a different direction each time.
An alternative to a gas-powered mower is an electric mower, either the plug in variety or the cordless model. One might even try a solar charged unit. Electric mowers, like the Neuton or Black & Decker, emit half the noise, weigh less, have negligible fumes and require lower maintenance. At $200 to $500, the initial cost may be higher, and a battery charge will take 60 to 90 minutes.
If your lawn is a half acre or less (5,000 to 8,000 square feet), you may opt for the most eco-friendly choice, the reel mower ($80 to $200). Be aware that some models don’t have the capacity to adjust as high as three inches, but the Scott’s Reel Mower is one that does. Also, it is advised not to take off more than one inch of blade per mowing with a reel mower, so more frequent mowing may be required. As an added benefit, you will burn approximately 300 calories per hour pushing a reel mower.
Natural Lawn Care: Efficient Watering
Careful monitoring of moisture levels and proper watering is another necessary and effective step in creating and maintaining a healthy lawn. Efficiency is key, however, as this is another cause of environmental abuse. Watering the lawn can consume more water than all other household functions put together, especially in the summer. About 8,000 gallons per year are used on the average American lawn, and according to the EPA, too high a percent is wasted through excess watering. This is a preventable expense of hundreds of dollars as well. The total amount of water a lawn should receive between you and Mother Nature is 1 inch per month to 1 inch weekly in the driest time. It is possible to overdo, as the soil needs to retain air as well.
Watering infrequently and deeply, leaving the top three inches of soil dry most of the time will cause roots to go deeper, giving the grass a survival advantage in drought and against weeds. Conversely, more frequent watering for shorter periods and to shallower depths only feeds the weeds, while causing roots of the grass to extend sideways, producing thatch.
Shallow-rooted grass will start to curl when heat stressed and then turn brown. Pushing a spade into the ground is a way to check the moisture conditions in the soil and judge whether watering is needed or not. Alternatively, one can purchase a soil-moisture sensor. A rain gauge is another useful monitoring tool. Some are even capable of turning on the sprinkler only when necessary.
Keep in mind that grass naturally will go dormant in the hotter months and green up again later. Finally, watering is best done in early morning (before 8 a.m.) as dampness left on grass all night after an evening watering can encourage fungal diseases to develop. Obviously, watering sidewalks and driveways is a waste. Another monitoring tip is, if your foot leaves an impression in the grass, the lawn needs watering.
By Steven G. Herbert. This article appears in the June 2013 issue of Acres U.S.A.
Steven Herbert is an earth scientist, transpersonal anthropologist and international dowser. He served as an agroforestry extension agent, and as a U.S. Peace Corps volunteer in Senegal, West Africa, before obtaining master gardener, master composter and urban and community forestry certifications through the state of Vermont where he now resides.