Late August is one of the best times of the year to repair an old lawn or start a new one. If you are planning to do some work on yours that involves digging. First of all give full consideration to the lime problem.

Most soils in the eastern part of the United States are too acid for best growth of lawn grasses. Lime is used to correct soil acidity. If you haven't limed your lawn for three or four years, probabilities are it needs it badly. If you have trouble with the lawn and it is in rather poor condition, that may be the main reason.

The nutrients that a plant gets from the soil are dissolved in the soil moisture and absorbed by the roots. If the soil is too acid or too alkaline, certain nutrients become insoluble and thus are unavailable for plant use.

When soil becomes strongly acid, toxic amounts of iron, aluminum and manganese restrict root growth. Lime chemically deactivates or removes these elements from the soil. When soils are quite acid, most of the phosphorus is tied up in an unsoluble form.

The best way to find out about your soil is to have it tested. However, if you are going to do late summer seeding, there isn't time for it. in such a situation, according to University of Maryland turf specialists, it is generally safe on areas to be planted to apply 80 pounds of limestone per 1,000 square feet of area.

The lime should be mixed thoroughly into the top 4 to 6 inches of soil before seeding. Since lime moves downward only about 1 to 1 1/2 inches per year in the soil, it is very important that it be mixed with the soil in the root zone so that acidity can be corrected fairly soon.

If ground limestone is used, it should be of a very fine grind. Because of its insolubility, limestone moves very slowly downward and very little outward. Fineness of grind does not increase solubility. It merely provides more surface. Acids work on the outer surface of lime particles. The more surface exposed, the faster it works.

In general it is recommended that ground limestone be purchased that has been ground so that 98 to 100 percent passes a 20-mesh sieve and at least 50 percent passes a 100-mesh sieve. This information should be on the bag of lime.

Large particles of lime may stay unreacted in the soil for years with little or no appreciable effect on soil acidity. But limestone dust may react within a few days. Dusty limestone may be more difficult tohandle, but it is worth the extra trouble.