Soil fertility management for vegetable gardens

Vegetable gardeners are always looking for ways to boost production, and one of those ways is to fertilize the garden soil. Sometimes fertilizer is applied in amounts well above what is necessary for good production; this can be damaging both to the crops and to the soil.

It is faulty to think that doubling or tripling the amount of fertilizer applied is okay so long as it continues to boost production. Yes, often there is a growth response with each additional amount of fertilizer applied; however, the increase becomes less and less proportional to each jump in the amount of fertilizer applied. At some point the extra fertilizer begins to have a negative effect on plant growth. Oftentimes, before the negative effects on plants appear there is a significant reduction in crop quality and production. It’s always better to apply the lowest amount of fertilizer that will produce the best proportional increase in production and crop quality.

Fortunately for gardeners, years of scientific research and actual field trials have made the information available to accurately assess the soil’s fertility and determine the how much fertilizer to apply to optimize vegetable production. There is a caveat—gardeners must have their garden soil tested. The information from the soil test becomes the foundation for the fertility management recommendation for your vegetable garden.

Soil testing is a precise laboratory process; but don’t worry, it is fairly inexpensive. A routine soil test checks the phosphate and potash in the soil. It does not measure all the phosphate and potash in the soil; rather, it measures only what the soil most likely has available for plants to use. Ideally, you want the level of available nutrients to fall within an optimum range. In some gardens the soil’s nutrient level is below the optimum range so a recommendation to apply fertilizer will be made to make up the difference. On the other hand, in gardens where the soil’s fertility is at or above the optimum range a recommendation to withhold fertilizer is given.

A very important point to make is that applying fertilizer should be done in a way that benefits the soil and the vegetable crops. Deep, dark and fertile; that’s the kind of soil all vegetable gardeners long for, but not every gardener is blessed with such beautiful soil. Soil testing along with the application of the recommended amount of fertilizer helps to make up the difference.

For more information, contact Jacob Weber, Horticulture Agent, at [email protected] or 620-724-8233.