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Organic Lawn Care Considerations






Most lawn experts agree that fertilizers with N (nitrogen), P (phosphorus), and K (potassium) analysis ratios of 3-1-2 or 4-1-2 are acceptable for use on any lawn. Most organic fertilizer have 3-10 percent nitrogen, which is usually slow to release, as it is "tied up" in complex organic molecules. It may take several weeks or months to become available to the plant.


Who doesn't like to walk across verdant expanses of lawn and breath in the fresh smells of soil and growing grass? Lawns of course offer much more than these sensory experiences. They serve to stabilize soil, prevent erosion, reduce runoff, filter surface water, absorb sound and reduce air pollution.

Technology has made caring for turf fairly easy and inexpensive for the landscape superintendent. Applications of small amounts of chemicals, for instance, can effectively reduce pest populations. This, coupled with proper cultural management can bring longer-lasting pest control than strictly nonchemical methods.

The environmental effects of certain turf care is not always clear cut. The ramifications of applying chemical pesticides and fertilizers continues to be evaluated.

For those superintendents who want to use a nonchemical approach to turf care, organic methods are more than about protecting the environment.

Organic lawn care from the start begins with selecting the right grass for the location. Adopting an organic turf strategy means your crew will not need to handle or breath dangerous chemical pesticides nor deal with their disposal.

Using organic fertilizers and biological and cultural pest management eliminates concerns about the effects of pesticide residue for those who walk your property (people and pets) or for the wildlife denizens. In short, many turf problems (weeds, diseases, insects) can be prevented or minimized with good planning and careful management of organic methods.

A Few Notes on Establishing a New Lawn

Grasses must be selected according to function and horticultural requirements, i.e., considerations such as active use, sun exposure, watering requirements, surface appearance and winter color. While it may sound too basic, consider the location of the lawn with regard to ease of maintenance and soil conditions. Grass does not grow well in very shady spots or in poorly drained soil, and it is a chore to maintain on steep slopes. Select grass suitable for your region and climate. North Carolina is an interesting example, as it has three climate zones--a coastal plain, rolling hills of the Piedmont in the center of the state and a western mountain region--that allow both cool and warm-season grasses to prosper.

In North Carolina, cool-season grasses, such as tall fescue, Kentucky bluegrass, fine fescue and perennial ryegrass, grow best in the spring and fall and stay reasonably green in the winter. They are best seeded from mid-August to mid-October. Spring seeding is less satisfactory, as the seedlings do not have time to become well established before the hotter weather begins.

Warm-season grasses grow slowly in the spring, grow will in summer, but go dormant after the first frost. They are seeded or planted (as springs or plugs) from March through July. Best results are usually obtained by planting dormant sprigs in March, although warm-season grasses can be planted through September if the temperature in the upper four inches of soil is above 55?F.

Some grasses are more resistant to disease than others. A mixture of several cultivars of cool-season grasses will reduce damage from diseases, such as mixing tall fescue with Kentucky bluegrass.

Ideally, you should plant the lawn during the season best suited to the variety selected. If you plant, the seed density must be adequate and may need watering to encourage emergence. After the seedlings emerge, watering, fertilization and mowing will ensure early growth.

All types of grasses benefit from high quality soil and an organic lawn fertilizer will improve long-term soil quality. Inorganic fertilizers are salt based, which cause imbalance in the pH of most soils and a toxic buildup of nitrates, according to the Better Lawn & Turf Institute. The pH of the soil determines the availability of nutrients to the grass. Turfgrasses used in North Carolina are not native and grow best in soils with a 6.5, except centipedegrass, which likes a pH near 5.5 (that is 10 times more acidic than 6.5). Grass near trees often suffers, as the soil by the tree may have a pH of 4.0 or lower.





Maintaining an Established Lawn

The entire root zone, which may extend down 6-8 inches, should have a consistent pH and be porous enough to let nutrients reach the deeper roots, otherwise the roots will struggle and may die during periods of stress.

Shade and reduced air movement allow humidity and moisture to remain high for long periods and promote disease. Trees and shrubs need to be pruned to reduce shade and improve air movement.

During dry weather, turfgrass should be watered once a week with about one-inch of water. Avoid frequent, light irrigation, as it keeps the foliage wet and favorable for disease development.

A reel mower is preferred for zoysiagrasa and hybrid bermudagrass. A rotary or reel mower is satisfactory for other grasses. Mowing grass too short causes stress, discourages deep root growth and results in rapid loss of soil moisture.

Letting grass grow too tall causes excess grass clippings that can smother the turf. Increase the mowing height .5-inch for shady areas, during a hot, dry period, or when the grass has been weakened by insect injury or high traffic.

The optimum height rule of thumb is to cut no more than one-third of the leaf surface. If you follow the rule, you won't have to collect grass clippings, especially with the mulching mowers on the market that cut the clippings very fine.

Fertilizing

The goal of any fertilization program is to provide the lawn with the nutrients it needs for optimum growth. The most accurate way to find out those needs is a soil test. To maintain a pH in the 6.0 range and prevent nutrient deficiencies, the soil should be tested every two to three years. For established lawns, the sampling depth is three inches. Lime may be place any time of the year, however, winter is often the best time, as there is less traffic and the alternative freezing and thawing help incorporate lime into the soil.

Nitrogen requirements cannot be determined by a soil test. To decrease susceptibility of turf to pest and environmental stress, do not apply high nitrogen fertilizer to cool-season grasses in the late spring or summer, or to warm-season grasses in the fall or winter.

Most lawn experts recommend that the fertilizer should have at least one-half of its nitrogen (N) in a slowly soluble/slow-release form, i.e. natural organics, sulfur-coated urea, resin-coated urea, ureaformaldehyde, methylene urea, or I.B.D.U. Lawns fertilized with one of these slow-release forms of nitrogen tend to have better color, thickness, and reduced leaf growth.

Most organic fertilizer have 3-10 percent nitrogen, which is usually slow to release, as it is "tied up" in complex organic molecules. It may take several weeks or months to become available to the plant. When fertilizing with organic fertilizers, expect slower green in the spring. Extended dry or cold periods may also delay release of the nitrogen.

The number of organic fertilizers is increasing in response to demand. Organic fertilizers come from animal, plant or mineral sources and contain no chemically formulated additives: livestock waste (bone meal, dried blood, manures) and municipal waste (vegetable meals, feather meal, fish scraps, crushed minerals).

Note: Read the fertilizer label. Some will say "organically based" or "natural-based" but will have man-make chemical formulations in the nutrients or pesticides added. (See Table above for more information on organic sources of fertilizers.)






A mulch-on-demand unit. Grass clippings make turf greener, tougher, prevent common turf diseases and reduce or eliminate fertilizer needs. Grasscycling provides about two pounds of nitrogen per 1,000 square feet of lawn per year.


Fertilizing Timing and Rates

The best time to fertilize your lawn is when it is actively growing and in need of nutrients. For southern lawns, this means beginning just after spring green-up and stopping about two months before the average frost date in the fall.

For northern lawns, start when the lawn begins to grow and green-up in the spring, then reduce applications as the weather gets hotter. When the cool weather returns in the fall, the lawn can again be fertilized. A late fall application, after the first frost, has been shown to increase lawn quality the following spring.

Fertilizing the turf when the soil pH is in the 6-6.5 range, when there is adequate moisture and oxygen, and temperatures are above 50-55?F are conditions favorable to microbial activity and enhance nutrient release. Do not fertilize when the grass is not growing. Nutrients not used by the grass will be available to weeds.

Fertilizer application rates should be as low as possible and still produce a high quality lawn. If the N number of the analysis on the bag is between 5 and 12, the application rate should be 8 pounds per 1,000 square feet of lawn. If the number is 12-18, the application should be 6 pounds per 1,000 sq. ft. Anything over 19 is applied at 4 pounds per 1,000 sq. ft.

Aerate

Compacted soil reduces drainage and inhibits root growth. Aerate via devices that remove soil cores, but after a soaking rain or irrigation that has penetrated 2-3 inches down. Aerate only when the grass is actively growing, so that it can recover from the injury. It is best to core cool-season grasses in the fall. Coring cool-season turf in the spring may promote weed growth. Core warm-season turf in the late spring or early summer.





Dethatching

Sod-forming grasses such as Kentucky bluegrass, bermudagrass, zoysiagrass, St. Augustinegrass and centipedegrass have a tendency to build a thatch layer when they are heavily fertilized and watered. If the thatch exceeds .5 inch, lawns should be dethatched via light power rakings instead of trying to remove too much at one time. Small accumulations of thatch (less than .75 inch) can be removed from warm-season grasses by mowing as low as possible ar the time of spring green-up and then raking. Use three-inch blade spacing on a power rake to avoid injury to centipedegrass and St. Augustinegrass.

Pest Management and Lawn Care

The most important step in pest management is to maintain healthy soil.

Good, healthy soil produces healthy turf that is better able to withstand plant diseases and insect damage. Efficient watering, planting, soil building, and reduction of rainfall runoff will significantly reduce your pest problems.

Insect infestations and diseases are often a symptom of stress caused by poor growing conditions, such as compacted soils, nutrient deficiencies, too much or too little moisture, or a poorly adapted plant for the climate or the particular landscape conditions. Simply correcting the stressful condition may control the pest and prevent further infestations.

Of the millions of kinds of insects in the world, less than two percent are harmful. Beneficial insects such as ground beetles, ladybugs, fireflies, green lacewings, praying mantis, spiders, and wasps keep harmful insects from devouring your plants. They also pollinate your plants and decompose organic matter. Chemicals harm these beneficial insects more than the unwanted pests. Mineral pesticides are dormant and horticultural oils and powdered diatomaceous earth have low toxicity and are safe to use.

Create a haven for beneficial insects. They will come to the landscape if they find fresh water (nonstagnant); annual flowers, perennial flowers, bulbs, grasses, small shrubs, large shrubs and deciduous and evergreen trees. Do not foget the birds and squirrels--they enjoy fruits, grain, and seeds, especially during the winter.



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October 17, 2019, 6:25 am PDT

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