Your local Cooperative Extension Service office may offer a professional soil testing service. The advantage is low cost and results that are specifically geared to your location. If this service is not available, you can also have your soil tested by an independent soil lab. If possible, choose one in your own region of the country. Soil test results usually rate the levels of soil pH, phosphorus, potassium, magnesium, calcium, and sometimes nitrogen.
Some labs also offer tests for micronutrients such as boron, zinc and manganese.
Unless you feel there may be a deficiency problem, you probably won t need micronutrient testing. Spring and fall are the best times to perform a soil test. The soil is more stable, and these are good times to incorporate any recommended fertilizers. Many labs will give recommendations for specific organic amendments upon request. If not, you will have to compare labels to find organic substitutes for the chemical fertilizers that may be suggested.