A healthy established lawn is able to out-compete many weeds and withstand a certain amount of pressure from disease and insect attack as well as drought. You can maintain a healthy lawn with proper fertilizing, liming, watering and mowing techniques.

Fertilizing:

Fertilizer applications should be based on soil tests. Research has shown that a fertilizer with percentages of nitrogen, phosphorus (P2O5) and potassium (K2O) in the ratio of 3-1-2 or 4-1-2 is the most efficient (least wasteful of any nutrients) for the established lawn. If such fertilizers are not available, a general purpose fertilizer (such as 10-10-10) can be used. No more than 3 to 4 lbs. of actual nitrogen (total amount of nitrogen actually in the fertilizer) should be applied to 1000 square feet of most lawns in a given year. Less may be used if clippings are left on the lawn. Excess nitrogen promotes lush, tender growth susceptible to disease, resulting in higher maintenance needs. Fertilizing at the wrong time of year can also lead to problems.

For the best lawn appearance, we generally recommend three applications of 1 lb. of N per 1000 square feet. The first application should be in the early spring, perhaps as late as Mother's Day (timing isn't critical unless you are using a fertilizer/herbicide combination--which we generally do not recommend). A second application around Labor Day will get the lawn growing again for the fall, and a third application around Thanksgiving will keep roots growing through the winter and result in early spring greenup. If you want to use less fertilizer, try applications 1 and 3 or just the first. Older, established lawns may need only one application, or perhaps fertilizer applications on less than an annual basis.

Several variables, including type of nitrogen (quick or slow-release), desired use and condition of turf and number and timing of fertilizer applications determine a fertilizing program. The fact sheet Developing a Fertility Program for Lawns provides a more complete discussion of lawn fertilizing. Calibrate your spreader to apply the proper amount of fertilizer. Do not apply fertilizer when grass leaves are wet. Water the lawn immediately after fertilizing to wash the fertilizer off the foliage and to prevent 'burning' the plants (unless the directions on the bag state otherwise).

Liming:

Ground limestone may be applied at any time of year, though late summer to early fall is best. No waiting period is generally necessary between liming and fertilizing. Most soils in Rhode Island are slightly acidic and can benefit from a general maintenance application of lime--usually 40 lbs. per 1000 square feet, but a soil pH test tells you exactly how much you need. Unless your soil is really acidic, a lime application every few years should be adequate. See GreenShare Factsheet on soil testing for more information on how test your soil.

Watering:

Unless watered regularly, a well-established lawn may naturally go into a dormant 'brown' period during the hot summer months. The lawn is not dead and will become green again in the fall when conditions are cooler and damper, unless the drought is pro-longed. However, allowing the lawn to go dormant may mask insect and disease problems--dead areas may be evident when greening does occur. If you water during the summer, do so regularly using the following guidelines:

• Water your lawn slowly and thoroughly, enough to wet to a depth of 4 to 6 inches. One inch of water (or rainfall) every week is probably sufficient, or you can let the grass be your guide. Light, frequent waterings are undesirable because they encourage shallow root systems.

• When the blades turn a dry, bluish green, the edges of the blades curl or a 'foot print' is left after walking, it is past the time to water--water as soon as possible

• Watering is best done in early morning to reduce waste and to reduce the chance of disease (foliage which is wet all night is more subject to disease).

For additional information on watering, see GreenShare Factsheet: Efficient Watering of Turf

Mowing:

A rule of thumb is to keep the lawn at a height of about two to three inches. Mow frequently enough that you do not remove more than one third of the leaf blade at one time. The lawn may be cut as low as 1-1/2 inches in the spring and fall, but it is best not to cut below 2 inches in the heat of the summer. During the summer, the lawn may even be left a little longer, 2-1/2 to 3 inches. Fescues and shady grasses are grown a little longer than bluegrass. There is a direct relationship between grass length and rooting depth, so grass kept too short is less able to withstand drought and stress. Too close a cut will make the lawn more susceptible to weed and insect problems as well.

It is not necessary to remove clippings from a lawn if it is mowed frequently. Do not let the lawn grow very high and then cut it back all at once; this can be a shock to the grass plants and can severely weaken them. This will also require the removal of the clippings so that they do not smother the lawn. If the lawn has become very long, shorten it gradually with a series of successively closer mowings. Use a sharp mower; the cut should be clean with no shredding or tearing of the plants. Do not mow or work on a lawn when it is frozen or very muddy. These practices can damage a lawn.

For additional information on mowing, see GreenShare Factsheet: Mowing.

Problems:

Weeds can best be held at a tolerable level by maintaining a dense, healthy lawn. If weeds become a problem, use an effective herbicide registered for their control. Hand weeding may also be a solution in some cases; be sure to remove the root system of the weed as well as its top growth.

Diseases are most likely to occur in lawns suffering from inadequate soil aeration or drainage, overwatering and/or improper fertilizing or mowing. Fungicides are rarely recommended for the home lawn, since proper maintenance is usually sufficient to keep disease problems to a minimum. Injury from other causes--burning with fertilizers or herbicides, dog damage, insect damage or drought--may be mistaken for disease symptoms. Insects such as the Japanese beetle and other grubs (rooteaters), chinch bugs (which suck plant juices), ants (which disturb soil by mounding) and other pests are common. A healthy lawn is able to survive light infestations, but severe insect problems may need to be dealt with by appropriate use of the proper insecticides.

Lawn Renovation:

Lawns sometimes deteriorate over a period of years to the point where they cannot be nurtured back to an acceptable level of quality using standard cultural practices such as fertilizing, proper watering, etc. The lawn may be in poor condition because improper grasses were used initially or have become "out of balance." Overuse, neglect, extensive thatch accumulation, disease, insect and/or mechanical damage or a heavy infestation of weeds are other reasons to renovate. Under circumstances such as these, renovation of the lawn may be necessary. Renovation consists of eliminating whatever factors cause poor quality, followed by reseeding without completely tilling under the lawn. The process of renovating may be as basic as simply reseeding bare spots, or as involved as killing all vegetation using a nonselective herbicide such as glyphosate (Roundup or Kleenup), followed by reseeding the entire lawn.

Timing:

Renovation during late summer (August 15 - September 15) generally yields the best results. Minimal weed competition as well as cooler temperatures and ample rainfall usually follow late summer renovation, thus providing a favorable environment for new seedlings. Late summer seeding must be accomplished early enough to allow the grass to become well established before the onset of cold weather in order to enhance winter survival. Renovation may be attempted during spring if absolutely necessary. As timing approaches late spring, however, extensive weed competition coupled with summer drought and heat stress reduce the probability of success.

Renovation Procedure:

The following procedure is designed for renovation of large areas of turf and/or entire lawns. If only a few small spots require reseeding, steps 2 and 3 may be omitted.

1. Correct whatever factors caused the lawn to deteriorate to the point of needing renovation. Re-contour the lawn if necessary, improve drainage, eliminate excessive shade, etc. Renovation will only yield temporary improvement unless the original cause of poor quality is remedied.

2. Control all weeds present. Most broadleaf weeds can be selectively eliminated by using glyphosate (Roundup). Small infestations of bunch-type (non-spreading) weedy grasses can be removed by digging. Remove the weed, grass and soil to a depth of about 2 to 3 inches. Remove soil for a distance of about 2 to 3 inches outside of the clump to ensure the removal of all the undesirable plant.

Perennial weeds which spread via rhizomes (underground creeping stems) or stolons (aboveground runners) cannot be controlled by digging. Spreading perennial grasses such as quackgrass and bentgrass should be controlled using a nonselective herbicide such as glyphosate (Roundup or Kleenup). It may be advisable to permit the lawn to grow slightly higher than normal prior to weed control to allow the weeds to grow larger, thus producing more leaf area for better herbicide uptake and control. Wait 10 to 14 days following herbicide application before proceeding with renovation in order to allow for complete herbicide uptake and allow any chemical residues in the soil to dissipate. Always follow label recommendations when using herbicides. Specific information concerning rate of application, weeds controlled, and waiting period before reseeding is stated on the label.

3. Mow the entire area as low as possible (1/2 to 3/4 inch) and remove all debris. If there is an appreciable accumulation of thatch (more than 1/2 inch), remove it at this time using a dethatcher (sometimes called a power rake or vertical mower). A dethatcher is a power-driven machine similar to a lawn mower, but with a series of vertical blades or tines which rotate on a horizontal shaft to remove surface debris and thatch. Several passes over the area may be needed to achieve desired results. Remove all debris created by this operation. See GreenShare Factsheet on thatch for more information.

4. Cultivate the soil in order to assure good seed-to-soil contact. This is an important step, since seed broadcast onto a lawn without proper cultivation will not survive. Cultivate using a dethatcher set to penetrate the soil to a depth of about 1/4 inch, exposing enough soil to provide a good seedbed for establishment. On small areas, a garden rake can be used to loosen soil to the proper depth.

5. Fertilize and lime (if necessary). Incorporate the materials into the soil at this time. Proper soil fertility and pH are essential for successful renovation. Base application rates of these materials on soil test results. Obtain a soil test three to four weeks prior to renovation, if possible. If soil test recommendations are unavailable, approximately 2 lbs. of phosphorus and potassium per 1000 sq. feet and approximately 1 lb. of nitrogen per 1000 sq. feet should be worked into the soil to promote seedling growth. "Starter" fertilizers which contain substantial phosphorous can be purchased for this purpose.

6. Following cultivation and fertilizer application, the lawn is ready to be seeded. Seed of a species similar to that existing in the lawn should be used unless improper species selection was the original cause of poor quality. Seed should be applied uniformly over the area to be renovated. Use a seeding rate for a new lawn if glyphosate was used on the entire area, or 1/2 rate if 50% of turf is still present. In order to insure uniform coverage, apply the seed in two directions made at right angles to each other. Enough seed should be applied to provide 15 to 25 seeds per square inch. For larger areas, consider renting a powered slit seeder.

7. Rake lightly following seeding (a leaf rake works well), or drag with a steel mat or door mat to work the seed into the soil to a depth of about 1/4 inch. The area should then be rolled to ensure good seed-to-soil contact. If the area being renovated is on a slope, apply a weed-free mulch to prevent erosion.

Post-Planting Care:

8. Water lightly and frequently, two to three times per day to keep the seed bed damp during the period of germination and establishment. The duration of germination and establishment will vary among grass species but will probably range from four to six weeks, with perennial ryegrass being the fastest species to establish and Kentucky bluegrass the slowest. Continue to mow the lawn on a regular basis during renovation.

9. Apply a balanced fertilizer to provide 1/2 to 1 lb. of nitrogen per 1000 sq. feet when seedlings are about 2 inches high. This will enhance growth and hasten the recovery of the lawn to the quality you desire.

 

Adapted from the University of Massachusetts, 1999