Pensacola News Journal

For: Saturday, May 3, 2003

By: Daniel E. Mullins

Extension Horticulture Agent

Santa Rosa County

Apply Lime Only if You Are Sure That It is Needed

An application of lime is sometimes needed in the landscape, but only after careful consideration. If needed, lime can greatly improve the growth and development of some plants. On the other hand if applied when not needed, long term problems can develop. Apply lime only if the need has been established by a soil test.

Many of our Gulf Coast soils are acid by nature. This is fine for azaleas, camellias, gardenias, blueberries, hollies, centipede, carpet grass, many natives and other so called “acid loving” plants. Since the naturally low pH is within an acceptable range for these, no adjustment by liming is required. In fact, an application of lime made to the soil can raise the pH excessively and interfere with this plant group’s ability to take up certain nutrients.

Some other plants might require an occasional application of lime. Many of our native soils have a pH in the range of 4.0 to 5.5. This is too acid for the best development of certain plants. Vegetable gardens prefer a soil pH of 5.8 to 6.3. Many annual and perennial flowering plants prefer a similar soil pH, while the St. Augustine, Bermuda and Zoysia grasses also sometimes benefit from an adjustment in pH.

Lime is generally used to sweeten or raise the soil pH and to supply calcium. Though there are several different kinds of lime on the market, dolomite or dolomitic limestone is the lime of choice for most situations. It is slower acting, non burning and has a good balance of calcium to magnesium.

Liming Considerations

■ Soil testing should be done approximately every 3 years. Contact your local Extension office or private laboratory for instructions prior to taking samples.

■ The laboratory should be made aware of the kinds of grass, flowers, shrubs or other plants to be grown in the area. The need for lime and amount if needed will be determined based upon the species being grown.

■ Lime is rarely required on an annual basis. If the correct amount is calculated and applied, another application is usually not necessary for several years.

■ Dolomite lime moves downward in the soil very slowly, so when needed it is best incorporated by tilling into the soil when preparing vegetable and flower beds. Do not till lime into the soil around perennial plants or obviously, into the lawn. Apply the recommended amount to the soil surface.

Question of the Week: Can carpet grass be used for a lawn in this area?

Answer: It can, but only under certain conditions. Carpet grass is adapted to only wet, acid conditions. It is found growing naturally around the edge of ponds and in marshy areas. If you have extra wet soil conditions, this might be the grass for you. If not, it would probably be a poor choice.

Sod of carpet grass might be difficult to find, as there is not as much demand for this species as there is for others. It can be started by seeding and seed is readily available.