Most soils in the Washington areas are naturally too acid for the best growth of vegetables and many kinds of ornamental plants.

String beans are an outstanding example. in severe cases, beans bloom but pods are not set on the plants.In less severe cases, bean pods are pale yellowish-green and the leaves are covered with browinsh spots.

Other crops are affected but symptoms may not be as prominent or noticeable as those of beans.

The best way to find out for sure about your own soil is to have it tested. Residents of the District can have it done free of charge by D.C. Cooperative Extension Service.

Residents of Maryland can have it doenfree at the University of Maryland and residents of Virginia free at Virginia Polytechnic Institute. Phone your county extension agent for instructions on how to take the soil samples and where to send them. He is listed in the phone book under County or Baltimore City Government.

The fall season is one of the best times to get the soil tested. If the soil is too acid, lime can be applied to reduce acidity. It takes time after application to become effective, and the lime can't be applied this fall in time to work for next summer's garden.

Most gardens plants do best in slightly acid soils.If the soil is too acid or too alkaline, many of the nutrients necessary for plant growth become unavailable.

Soil samples tested at the University of Maryland have shown that the soil of many lawns is too acid for good grass growth. Even azaleas, which require an acid soil, are growing in gardens where the soil is too acid for them.

Not all of us fully understand the importance of timing when applying lime, according to Dr. K.A. Janssen, soil scientist, Eastern Shore branch, Virginia Polytechnic Institute. Lime, unlike fertilizer, is a slow-acting product that takes several months to neutralize acid soils.

If a time span between lime application and planting is less than three months, there is a problem if the soil is too acid. In such a situation, one of the quicker - reacting liming materials (pulverized lime, or hydrated lime) can be applied.

Cost of these quicker-acting materials is normally higher but improved crop performance during the next gardening season nearly always results in much better production.

Immediate and thorough incorporation of the liming material is also important when speedy lime reactions are required. Lime is a contact material and must come into contact with the soil in order to neutralize soil acids.

If lime is left on the soil surface, it is not going to react very fast.

Most important, maintains a slightly acid soil at all times and don't let it become too acid before applying time, Janssen says. If you do this, it will allow you more flexibility in the time of lime application and also in the choice of liming materials.

A soil test is of no real value unless the samples of soil to be tested is a good representative of the conditions that exist. This means that several random samples (the number depending upon the size of the area to be tested) should be taken and mixed together to give an average or composite sample. The extension agent will provide instrutions on how to take the samples. They should be followed closely.