Soil generally falls into one of three categories; good, poor and ideal. Chances are good that your soil is one of the first two. Gardeners know that the better the soil, the better the crop yields, so yours probably could use some improvement. Adjusting soil pH is just one step toward achieving ideal soil.

The term "pH" is a numerical value, between 0 and 14, that describes the degree of acidity or alkalinity of the soil. Your soil's pH reading is what will determine your course of action. A reading of 7.0 is considered neutral. Anything below that is acidic and anything above it is alkaline.

Most of the nutrients that reside in soil are available to plants when the soil's pH is between 6.0 and 7.0, so most plants will grow their best when the soil is in that range. Do-it-yourself soil testing kits are available at your local lawn and garden supplier. Once you know the reading, you can adjust your soil accordingly.

To raise your soil's pH, use limestone (calcium carbonate) or dolomitic lime. Pelletized lime, applied correctly, will raise soil pH to the desired level within a week or so. The easy-to-use pellets make application with a spreader quick and easy. Hydrated lime, available in a 5-pound box, is ideal for flower and vegetable gardens.

Lowering the soil's pH requires adding organic material such as peat moss. You'll see best results if this is done at planting time rather than after. You can apply a sulfur compound such as aluminum sulfate as well. Remember to fertilize acid loving plants.

Always make your soil improvements before planting. The materials you add to the soil will be easier to apply and will be more effective when worked into the soil beforehand.