Question:
Should I apply lime to my garden?Answer:
In Iowa, gardeners should apply lime to gardens and lawns only when recommended by a soil test. A soil test will indicate the current soil pH and, if necessary, the amount of lime to apply to the area. Liming materials include ground limestone which is mainly calcium carbonate (CaCO3) and dolomitic limestone which contains calcium carbonate and magnesium carbonate (MgCO3).
Lime is applied to acidic soils to raise the soil pH. The soil pH is important because it affects the availability of essential nutrients. The pH scale runs from 0 to 14. Any pH below 7.0 is acidic and any pH above 7.0 is alkaline. A pH of 7.0 indicates a neutral soil. The optimum pH range for most flowers, vegetables and other horticultural crops is between 6.0 and 7.0. Lime is applied to acidic soils with a pH below 6.0 to raise the pH into the optimum range. However, an application of lime to an alkaline soil can raise the soil pH to excessively high levels, reducing the availability of plant nutrients and leading to poor plant growth.