Applying Lawn Lime To Acid Soil For A Better Lawn
Summary: Apply lawn lime to acid soil is a corrective action to help neutralize lawn soil. When soil is excessive acidity it hinders the growth of grass and are subjected to more frequent attacks by fungus diseases since fungal generally grow better in an acid medium.
Question: We have heard that an application of lawn lime will help soil and grass grow plus help improve the health and soil texture of our lawn. Can you explain the benefits lawn lime and why liming the soil is a good idea. Matt, Lynchburg, Virginia
Answer: Matt, the value of lime as an aid in producing bigger crops on some soils has been recognized for many years. This is not because lime is valuable as a plant food elements, but because it neutralizes soil acidity.
A large percentage of lawns and other grass areas do not require lime, the lawn soil condition being such that nothing would be gained by liming, and some harm might even result.
When actually needed, lawn lime may prove of great benefit to grass. Soil lime works to help correct soil acidity or sourness. It helps in making certain plant food elements available to grass, and, in addition, it is a direct source of calcium and magnesium, which grass plants need in small amounts.
Lawn lime should not be considered as a substitute for fertilizer. It does not provide those food elements that are of such vital importance to grass and which are lacking in practically all soils, namely, nitrogen, phosphorus and potassium.
Soil Acidity
For simplicity’s sake, chemists have devised a scale for designating hydrogen ion concentration or intensity of acidity. The unit of measurement is known as pH. The neutral point on the scale, indicated by 7 is the pH value of distilled water. Values lower than pH 7 indicate degrees of acidity while those higher indicate degrees of alkalinity. The pH values represent intensity of acidity or alkalinity and not quantities of acid or alkali present.
Fortunately, lawn and turf grasses will grow over a wide range of soil acidity and alkalinity, although the moderately acid soils varying from pH 6.0 to 6.5 probably are best. If the acidity is more intense than pH 6, lime will be needed. Soils can be too alkaline for grass but this is rare.
Excessive acidity hinders the growth of grass. It interferes with the activity of certain bacteria which change raw plant food elements into forms usable by grass. Undue acidity, preventing decay of organic matter, may mat the turf with dead roots which will diminish the circulation of air and water in heavier soils.
A turf on an extremely acid soil may be subjected to frequent attacks by lawn fungus diseases since the causal fungi generally grow better in an acid medium.
Indications of Acid Soil
The appearance of grass as an indication of soil acidity is not to be trusted. There is some evidence of the need of lawn lime in a shallow grass root system, the appearance of certain weeds, and otherwise unaccountable lack of response to fertilizer. Several causes connected with food supply, soil texture and drainage, may produce similar appearances. The sure way to know if lime is needed is to learn the pH value with a soil test.
Putting greens and other areas that have been much stimulated by acid producing fertilizers are often very acid, especially if the soil has a natural tendency toward acidity.
The growth of moss may be the result of an acid soil but is more likely to result from a deficiency in plant nutrients, poor drainage or excessive shade.
To use unneeded lime on a soil is wasteful and may be harmful. If a laboratory test of the pH value of the soil shows that lime is needed, it should be applied properly, in the best form, at the best time, and in the required amount.
When to Lime
Lawn lime is most effective when mixed with the soil to the normal depth of the grass roots. On an established lawn where only surface application can be made, penetration is best accomplished during periods of alternate freezing and thawing. Therefore, it is best to make application of lime in the late fall, winter, or early spring.
In case of a newly prepared seed bed, lawn lime can be raked or mixed into the upper six inches. The season is of no consequence except that application is best made several weeks or even months before seeding.
Lime may be applied after plowing under a green manure crop or a heavy stand of grass and before preparation of the seed bed. This will stimulate the bacteria that break down the organic matter and liberate plant food.
Forms of Lime
The term lime, referring strictly to calcium oxide, has been broadened to include various commercial compounds of calcium and magnesium which are commonly used to overcome soil acidity what is called “dolomite lime”. In most localities the only suitable forms are ground limestone and hydrated lime.
Ground limestone is native limestone crushed to an effective degree of fineness. For overcoming soil acidity, it should contain about 50 per cent of calcium oxide and should be fine enough so that about 75 per cent will pass through a 100 mesh screen and all through a 20 mesh screen.
Hydrated lime is made by heating ground limestone to such a temperature that the carbon dioxide and water are driven off. This makes burned lime, which is very caustic. By slaking with a fine spray of water as the burned lime is forced through a blower, hydrated lime is formed. A good quality tests about 75 per cent calcium oxide.
Quantities of Lime
A prescription for the use of lawn lime cannot be written unless an accurate soil test is made. When the pH and the soil type are known the proper amount of a given form of lime may be calculated.
Except in extreme cases, the quantity of lime required will vary from 50 to 100 pounds per 1000 square feet, or from one ton to two tons per acre.
In liming established turf areas, not more than 50 pounds of lime per 1,000 square feet should be used in a single application. If more is needed the application should be divided among several seasons. In preparation of a new seed bed, the entire quantity desired may be added at one time, but it should be thoroughly harrowed or raked into the upper five or six inches.
It is especially difficult to change the reaction of silt or clay that is well fortified with organic matter; hence such soils require more lime than a light, sandy soil having the same intensity of acidity.
It is far better to lime too little than too much. An overdose may upset the chemical balance of the soil, causing starvation of the grass plants and permitting certain weeds to gain control of the lawn.
Lawn lime may be broadcast by hand or, better, with a mechanical spreader such as used for lawn fertilizer. Such spreaders are available in small sizes for home use, as well as in large tractor-drawn equipment.
It is important to spread evenly since the lime will not move laterally through the ground, but only downward. On established turf areas, the lime should be washed or brushed off the grass leaves to prevent burning.
Native Limestone Country
The need of a soil for lime may depend largely upon the nature of its parent material, and upon the extent of leaching of alkalies.
Soils of the Atlantic Seaboard and New England States are likely to be acid because of their derivation from granites, sandstones or shales. Also, soils in New York State and northern Pennsylvania tend toward acidity, as do those of eastern Ohio.
In other parts of the country soils may be alkaline. In southern Pennsylvania there is much natural limestone. Beginning in western Ohio and extending through Indiana, Illinois, Wisconsin and into the far west, soils are generally of limestone origin.
However, it is not safe to infer the acidity or alkalinity of a soil from the fact of its location in any such division of the country. There are many modifying factors. Conditions may vary, even on adjoining properties. The maintenance program may cause an alkaline soil to become acid. Or, an alkaline condition may be maintained because of regular sprinkling with water that is strong in lime, or because of frequent topdressing with soil containing lime. A soil test is the safe guide.
Lawn Fertilizing – The Last Supper of The Year
The time has come for a final lawn fertilizing. The lawn “knows” winter is knocking on the door and heading into dormancy.
Before you put the fertilizer spreader away for the season, take one last stroll around the yard and give your lawn some extra nutrition before the ground freezes.
This last lawn fertilizer application of the season, provides the roots with food to store up carbohydrates.
This carbs will be laying in reserve to give a quick green up when the warm spring weather comes calling.
For this last feast of lawn food you’ll want a apply a slow release winterizing fertilizer with a high first number.
A typical slow release winterizing fertilizer would carry an analysis on the bag of 12-8-16, 10-0-15 or 20-2-6 or similar numbers on the bag.
The numbers break down as follows:
- First number – nitrogen
- Second number – phosphorus – helps with production of root growth
- Third number – potassium – gives an extra boost to plant’s flowers and fruits
Add Some Gourmet Organic Food
Leaf mulch makes great fertilizer and are an excellent source of organics. Leaf mulch and grass clippings which are about 80% water helps build the soil, returning much-needed nutrients back into your lawn.
Instead of bagging, continue to mow (a mulching mower is best) and mulch them into your lawn. Mulching mowers finely chop leaf clippings and grass so bagging is not required.
You many also want to use other natural fertilizers like fish blood, bone meal or chicken manure. Once applied they need be raked into the soil.
The Last Mow
If you have not done the last mow for the season, the time has come to lower the mower deck for the last ride or last push, over the turf and put your grass to bed. The lower cutting reduces the for disease to take hold.
If you live in New Jersey, as of November 15th, the DEP (Department of Environmental Protection) says NJ homeowners can no longer apply fertilizer to their lawns this season – the deadline has passed.
Commercial applicators have until December 1 complete their late Fall lawn fertilizer applications. Fertilizer can be applied to lawns again starting March 1st.
So wind up the lawn season before winter comes calling (unless you live in Jersey) – fertilize the lawn with a slow release winterizing fertilizer formula, mulch the leaves into the lawn and give the grass one last mow on a lower setting.
Lawn Nitrogen Most Important Fertility Element
Summary: The most important element required in maintaining the fertility of a lawn is the nitrogen available. This helps in keeping the rich green color and developing a strong root system.
Ammoniacal nitrogen has an acidifying influence on soil. Ammonium sulfate, for example, neutralizes six or seven times its weight in lime (calcium carbonate).
Ordinarily there is sufficient organic material and weak acids in the soil to buffer the influence of acidifying fertilizer. Most fertilizers can be used for years before the pH is appreciably lowered.
A soil test at intervals can suggest whether lime is needed.
In most instances a pH from 6 to 7 (slightly acid) is appropriate both for rose beds and lawns. Too much lime may raise the pH to around 8, turning phosphorus and other elements “unavailable,” causing blanching or chlorosis.
Water in limestone country and where lime is used in purification may be alkaline enough to compensate for acidity introduced from fertilizers. In alkaline soils of the arid West, it may be necessary to acidify more than is possible through fertilization.
Sulfur is usually used, although gypsum, aluminum sulfate or acids themselves can be employed.
In the lawn, nitrogen is the most important fertility element and a major concern because of the large area to be covered.
Chemical fertilizers are least expensive and adequate for good bluegrass if applied frequently, in cooler weather especially. Chance of burn is eliminated with the synthetic organics, used at higher rates less frequently.
Both grass and roses need fertilizer during their major seasons of growth. Which type is as much a matter of personal preference as of plant need. Lawn fertilizers may be used occasionally on the roses, but are best not employed late in the season, and alternated with phosphatic fertilizers or organics.
Manures or organics are generally more important to the rose bed than to the lawn. Organics help soil balance, something grass does for itself through return of fibrous roots and clippings.
For most soils there need be no fear of chemicals in any good fertilizer, or in the water supply, nor of appreciable alteration in acidity-alkalinity and trace element availability.
Lawn Safety – Water After Fertilizing
Potassium salts, like soluble nitrogen, can cause burning. Fortunately most chemical fertilizers are now made in the pelleted rather than in dusty form; the buckshot-like prills roll off the upright bluegrass-fescue blades, making these fertilizers relatively nonhazardous. For assured safety, the lawn can be watered after fertilizer application, to wash all fertilizer dust from the foliage.
Superphosphate is the main source of P, although some rose fanciers still utilize bone meal (an organic source). Phosphate becomes fixed in most soils, so it is not lost by leaching. There is scant danger of overdosage or burn from phosphate.
Adequate sulfur is usually in the soil or becomes added in rainfall and from sulfur in superphosphate. Thus potassium as the chloride rather than the sulfate ordinarily makes little difference. There has been some fear that chlorides might build toxicity. However potassium chloride is readily soluble, with excesses soon washed away. Ordinarily there need be no fear of muriate of potash as the potassium source in a fertilizer, or of chlorine-treated city water used for irrigation.
Nitrogen in Lawn Fertilizer
A garden fertilizer of ample phosphatic content is customary for roses, – although the excess nitrogen from a lawn fertilizer would ordinarily be dissipated without harm. Fertilizers high in nitrogen should be avoided towards the end of the rose season – just as it becomes most needed by bluegrass-fescue.
Lawn Fertilizers and Lime
The soil for a lawn should be neutral or only very slightly acid.
Where there is doubt as to the degree of acidity it is well to have it tested. Ordinarily an application of fifty pounds of finely pulverized raw limestone per one thousand square feet of surface is beneficial. The farther in advance of seeding this can be applied, the better.
Even if a considerable amount of manure has been used in preparing the soil of a top layer of compost, fertilizer should be added. Thirty to fifty pounds for each thousand square feet of a complete fertilizer containing approximately five percent of nitrogen, ten of phosphoric acid and five of potash (known as a 5-10-5 formula) is a satisfactory application for normal conditions.
It is highly important to get the fertilizer spread very evenly. While this can be done by hand and very inexpensive fertilizer spreader makes the job much easier. Check with a neighbor they probably picked one up for a nominal cost where lawn fertilizers are sold like Lowe’s and Home Depot. Where lime cannot be applied well in advance of seeding, the amount of fertilizer can be somewhat reduced and bonemeal used in its place, since it tends to neutralize soil acidity. and works more quickly than the ground limestone. Apply at the rate of about twenty-five pounds per thousand square feet.
With the fertilizer spread evenly on top of the compost layer both should be thoroughly mixed with the soil below by cultivating or a light forking over preparatory to raking the surface smooth and even with an iron rake. After the first raking, going over the surface with a fairly heavy roller will reveal depressions and soft spots that can be leveled up before the final raking to leave the surface ready to receive seed.
In the great majority of cases a well prepared mixture of several species of grasses gives the best turf. Reliable formulas have been worked out for different areas of the country. The last thing to do in building a lawn is to try to economize on the seed. The cost of the seed is only a fraction of the total expense involved and poor seed may completely ruin the result. The mixture procured should be one that is adapted to the conditions to be met, such as type of soil, full sun, partial shade and steep slopes.
