Q • How do I know how much to fertilize my vegetable garden without harming my plants or the environment?
Getting a soil test through your local county extension office is the best way to determine if your soil needs any fertilizer.
Nutrients are important for plant growth, but adding excessive amounts can be environmentally damaging and harm, rather than help, your plants. Many soils that have not been intensively farmed in the past have ample nutrients, and getting a soil test every three to five years will let you know if your soil has become depleted of any specific nutrients.
The No. 1 nutrient that most plants need regularly supplied to them is nitrogen. How much nitrogen your soil needs depends on the specific crop you are growing and the amount of organic material in your soil. The math can be tricky but using the information from your soil test and a fertilizer calculator like this one can help make it simple: agebb.missouri.edu/fertcalc/.
Additionally, regularly adding compost is the best way to build your soil organic matter and it is one of the best slow release organic fertilizers available. As the organic matter breaks down, nitrogen and other nutrients are slowly released, feeding your vegetables over the season. You can find more information on fertilizing vegetables through the University of Nebraska-Lincoln’s online publication: tinyurl.com/72tkfrw8.
Write to the Missouri Botanical Garden’s Center for Home Gardening at [email protected] or the Horticulture Answer Service, 4344 Shaw Blvd., St. Louis, MO 63110.