Write an article based on this "Test your soil's pH level Buy soil additive from a gardening supply store. Spread additive using a lime or fertilizer spreader. Monitor soil and reapply additive annually or as needed."
to determine which additive you need. The most common way to add calcium to soil is to use a soil additive. The two most common soil additives to raise calcium levels are lime and gypsum. Before choosing one, test your soil’s pH to figure out which one will work best for your needs.  If you need to raise your pH, use lime.  If you need your pH to remain stable, use gypsum. You can buy gypsum or lime at most gardening supply stores. For instance, you will usually be able to find them in the gardening section of stores like Home Depot and Lowes. You can also buy them online from Amazon and other stores. If you need to spread just a bit of additive, use your hands (just make sure you wash them before touching anything else!). But if you are trying to cover a larger area you may want to use a fertilizer spreader to be more efficient.  The amount of additive you need to apply will depend largely on your needs and your soil pH level. Research your needs before determining the amount you want to use.  If you are using lime, till it into the soil so that it mixes in thoroughly.  If you are using gypsum, spread it over the surface of the soil and then water it in until the soil absorbs it. You might only need to add more lime or gypsum once every year, but keep a close eye on your soil to determine how often you need to add calcium. If your soil is used to produce large amounts of crops, for instance, you may need to add calcium more frequently.