Garden Docs: If your garden is tired, it might be time to test its soil

Dennis G. of Santa Rosa asks: I was told by my neighbor, that I should have my soil tested because, after years of growing vegetables and annuals, they are not doing as well as in years past. How will this help?

Answer: Even though you've been growing in your garden for many years and think you know your soil, guess again. Soil testing is important to help understand the underlying chemical and biological dynamics of your soil. Although doing a soil analysis is just one piece of information that can help guide you in making decisions, it is a critical first step before you apply any soil amendments.

Most soil analyses for vegetable production will provide a measure of nutrient availability. Soil testing labs measure phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). Micronutrients commonly measured by a soil test include boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn). There are many types of soil tests and many different options for testing. For most home gardeners, starting with a standard soil test for nitrogen, phosphorus, and potassium, plus an organic matter analysis, should suffice for a basic soil fertility plan.

___

Susan K. of Windsor asks: What is a cover crop and when should you add it to your garden?

Answer: Planting cover crops is a great way to improve your soil. Cover crops can help your soil in many ways, such as increasing the soil organic matter, fixing nitrogen, breaking up compaction, suppressing weeds and preventing erosion. There are many plants to choose from for fall cover crops and the benefits of each are all equally important.

For home gardeners, it is recommended to sow the cover crops simply by hand-broadcasting the seed over freshly turned soil, then raking in lightly just before a rain.

Before the mature crop sets seed, it should be cut with a scythe or mower, then left as mulch for the rest of the season or turned under with a rototiller. Because the nutrients are tied up by the decomposing crop, you should wait 2-3 weeks after tilling it in before planting another crop into the area. At this point the cover crop cuttings will have mostly decomposed, making the organic matter and nutrients available for the next crop.

___

Send your gardening questions to The Garden Doctors at pdgardendoctor@gmail.com. The Garden Doctors can answer questions only through their column, which appears twice a month in the newspaper and online at pressdemocrat.com.