Reasons for Liming
Lime is usually added to garden soil when the soil is too acidic to support optimal plant growth. The materials commonly called lime contain calcium, and when calcium is added to the soil, it gradually raises the pH level of the soil, making the soil less acidic and more hospitable to beneficial microorganisms. Lime also provides a source of nutrients such as calcium, phosphorus and magnesium for plants, and it helps plants to better utilize fertilizers.
Lime products are usually made from either calcitic or dolomitic lime. Calcitic lime contains only calcium carbonate, while dolomitic lime contains both calcium carbonate and magnesium carbonates.
Pelletized lime is made by grinding agricultural lime, which may be either calcitic or dolomitic, into a fine powder. After the lime is ground, it is granulated, or pelletized, by binding it together using compounds called lignosulfonates. In the final pelletized product, lignosulfonates make up about 9 percent of the pellet.
Pelletized Lime vs. Ag Lime
Pelletized lime raises soil pH as effectively and at essentially the same rate as agricultural lime, which is commonly called ag lime. Ag lime, however, must be applied with a special spreader because of its finer texture, while pelletized lime can be applied with an ordinary garden spreader. Pelletized lime is also less messy than ag lime, which is dusty and difficult to apply on windy days.
Pelletized lime can be broadcast on top of the soil and doesn't need to be tilled in the same way that ag lime does, but pelletized lime must be watered after application to begin to dissolve the pellets and help the lime infiltrate the soil.
Pelletized Lime vs. Powdered Lime
Powdered lime products are even more finely ground than ag lime and are thus even messier and harder to apply. Pelletized lime has the same advantages over these powdered products as it does over ag lime.
Pelletized lime's principal disadvantage in comparison to both ag lime and powdered lime is its cost. Pelletized lime is more expensive than either of the other kinds of lime, so it typically isn't feasible for use in large-scale applications. On a small scale in the garden, however, the advantages of pelletized lime may outweigh its premium price.
Applying too much lime can make soil inhospitable to plants by making nutrients such as iron, manganese and zinc unavailable to them, so you should not lime your lawn or garden soil if you don't need to.
Contact your local cooperative extension office to find out how to have your soil's pH tested, and compare the test result to the preferred pH level of the plants you intend to grow. Many types of turf grasses and garden vegetables grow well in slightly acidic soils, so you may not have to raise the soil's pH level at all.