John R. Street
William E. Pound
Fertilization is the single most important lawn procedure to improve lawn quality and to maintain a high quality, healthy lawn. The most important nutrient in the lawn fertilization program is nitrogen. Nitrogen helps promote green color and a thick, dense lawn. Nitrogen does, however, stimulate topgrowth (clippings). The more nitrogen applied, the more topgrowth. Improper application of nitrogen fertilizer will result in lawn mowing nightmares and unhappy results with the Don't Bag It program. It is essential in the Don't Bag It program to apply the proper amount and kind of nitrogen and to apply it at the right times of the year to control growth.
The fertilizer plan in Table 1 is designed to allow the lawn to grow at a reasonable rate
and still have good color and density.
|Table 1. Fertilizer schedule.|
|Application Date (every 8-10 weeks)|
|Examples of fertilizer grades||(Pounds fertilizer per 1,000 sq.ft.)|
|10-6-4||5||5 to 10||10||10 to 20|
|15-3-3, 15-5-10||3||3 to 7||7||7 to 13|
|19-3-3, 19-5-10, 20-4-8||3||3 to 5||5||5 to 10|
|24-4-8, 24-4-12||2||2 to 4||4||4 to 8|
|28-4-12, 28-3-3, 29-3-5||2||2 to 4||4||4 to 7|
|34-5-5, 34-5-10||2||2 to 3||3||3 to 6|
|*The October, November or December feeding is late fall fertilization. Earlier date for northern Ohio and later date for southern Ohio.|
University research has shown that fall (August or September) and late fall (October, November or December) fertilization is ideal for home lawns. Fertilizations during these times will benefit lawns more than any other practice. Most homeowners place too much emphasis on spring and summer fertilization. Some fertilizer is needed during the spring and summer; however, over-application of fertilizer at these times can cause disease, rapid growth requiring much more frequent mowing and other problems that result in "summer lawn nightmares."
Disease and weed problems are usually less severe when fall and late fall fertilization are practiced. Heat and drought tolerance are usually better, thus enhancing summer lawn quality. Finally, the grass plant produces more root mass and a deeper root system, resulting in an overall healthier plant. Clipping production is usually less in the spring and summer when late fall fertilization is practiced.
How do you choose between products with the same nutrient content? The big choice is between fast and slow release of the nitrogen fraction. The percentage of the total nitrogen that is water insoluble and that which is water soluble usually is listed on the fertilizer bag. In the water soluble form the nitrogen is available quickly and in the insoluble form it is available slowly.
A good turf fertilizer contains some of each kind of nitrogen. The slow release portion provides nitrogen over a period of time for slow, even growth. The slow release portion is critical to reducing rapid topgrowth and the need for more frequent mowing. The soluble fraction, or fast release, will provide nitrogen almost immediately after application for a quick response and during cool weather. Something approaching 30 percent to 50 percent insoluble or slow release (time released) nitrogen is suggested.
Apply nitrogen fertilizer every eight to ten weeks at a moderate amount with a portion being slow release.
A major detriment to lawn attractiveness during the summer is a lack of soil water. During the hot, dry periods, growth of most of our lawn grasses will cease and the grass will turn brown and go dormant if supplemental water is not provided. The dormant grass is in a resting stage and will normally revive with favorable moisture and temperature conditions in the fall. Lawn attractiveness is, however, lost during dormancy, and weed growth, which detracts from the appearance of the lawn, may be greater. Dormant lawns will not normally need to be mowed.
During the driest period of the summer, our lawns usually will require about one inch of water every week to stay green and growing. Lawn sprinklers usually need to be set for at least one to two hours per spot to apply one inch of water. One inch of water will typically wet a soil to a depth of six to eight inches. Overwatering and/or frequent watering will stimulate excessive topgrowth and the need for more frequent mowing. Lawns watered too frequently also tend to develop shallow roots, which may make them more susceptible to pests and heat-drought stress. Water infrequently (weekly) and deeply (six to eight inches) with one inch of water each time.
The best time to water is early morning, so less water is lost by evaporation. The worst time to water is in the evening because the lawn stays wet all night, which encourages disease development.
Water infrequently (weekly) and deeply (one inch of water per time) when necessary.
Thatch is a tightly intermingled layer of living and dead stems, leaves and roots of grass that develops between the green grass and the soil surface. The overall effect of a thatch layer is an unthrifty lawn that does not respond well to management practices and is easily injured when conditions are optimum for growth.
It is assumed that the return of grass clippings to the lawn will increase thatch. This is not true. Grass clippings are about 75 to 85 percent water and decompose readily. Thatch is formed from grass parts more resistant to decay like roots, stems, nodes, crowns, etc.
Grass clippings do not contribute significantly to thatch accumulation on lawns.
The Don't Bag It lawn care plan can save the homeowner time, energy and money, and reduce the amount of waste going to our landfills. The principle is simple - return clippings to your lawn. By leaving your clippings on the lawn and allowing them to work their way back into soil, you can realize these benefits and still maintain a beautiful, green lawn.
In fact, grass clippings contain valuable nutrients that can generate up to 25 percent of your lawn's total fertilizer needs. A hundred pounds of grass clippings can generate and recycle as much as three to four pounds of nitrogen, one-half to one pound of phosphorus, and two to three pounds of potassium back to the lawn. These are the three most important nutrients needed by lawns and commonly supplied in lawn fertilizers. The other good news is that grass clippings do not contribute to thatch (an organic debris layer between the soil and live grass) since grass clippings are 75-85 percent water and decompose readily.
Why, then, do many homeowners bag grass clippings? Basically, it is a personal preference and habit most homeowners have acquired. Another reason is that bagging does ensure that no clippings remain on the lawn to detract from lawn quality and aesthetics. Proper lawn care practices will usually eliminate surface clipping debris and ensure a successful Don't Bag It program.
All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.
Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.
TDD No. 800-589-8292 (Ohio only) or 614-292-6181