Most plants prefer to grow in a soil that is only slightly acidic to neutral or basic. Gardeners with acidic soil have a number of ways to make up for low pH soil, with little lime content. Lime is a soil additive that raises pH, correcting acidic soil, but also affecting the availability of certain nutrients. A few fertilizers also have a "liming effect," raising the pH of the soil.
Understanding the effects of lime or a liming fertilizer on your soil requires understanding the role of pH in plant health. Most soil pH ranges from acidic to slightly alkaline, depending on the types of rocks that make up the soil. In addition, different plants like different soil pH levels. For instance, rhododendrons and blueberries famously like acidic soil that would harm other plants. Soil pH also affects the availability of some nutrients. According the University of Florida IFAS Extension, acidic soils tend to also have toxic levels of aluminum, iron and zinc, while calcium, magnesium and potassium may be deficient.
Toxicity or deficiency may provide the first clue that you need to raise the pH of your soil. Lime and some fertilizers temporarily raise the soil pH, creating an environment more conducive to the growth of most plant species. A routine soil test includes a pH test and, according to the University of Florida IFAS Extension, a lime requirement test provides further information about how much lime you need to add in order to correct your soil pH. University of Florida Extension advises gardeners to apply lime only after having their soil tested.
Gardeners sometimes speak of a fertilizer or soil amendment having a "liming" effect or will say that a specific product is a source of lime. In the generic sense of the term, lime refers to any substance that will raise the soil pH. For example, the nitrogen fertilizer calcium nitrate exerts a liming effect on soils. Applying such a fertilizer to the soil will not only raise the soil pH, but will also provide additional nutrients for plants to use, according to Mississippi State University Extension.
While pH changes following lime application may make nutrients more available in your soil, according to the Mississippi State University Extension Service, lime alone is not a fertilizer. It only adjusts soil pH and does not provide additional plant nutrients, meaning that it must be applied in addition to any fertilizers used to address nutritional needs. MSU Extension states that fertilizers that raise soil pH in addition to providing nutrients include sodium nitrate, calcium nitrate and hardwood ashes.
Choosing a liming agent depends on the needs of your soil. According to the Clemson Cooperative Extension, finer-ground materials change the pH faster. Since limestone doesn't dissolve well in water, it is important for the material to be incorporated into the soil for it to work. If a soil test reveals nutritional deficiencies, a product that fertilizes in addition to adjusting pH may be warranted, or you will have to apply a fertilizer in addition to lime.