How do I test the soil in my garden?
You should test the soil in your garden or in specific areas of your garden for a number of reasons. If you have moved to a new house, you'll need to know the suitability of your new environment to plants and whether you need to make any major changes to your soil. If plants are not doing well in a certain beds in your present garden, a soil test may help you find out why. In addition, soil test results can enable you to avoid needless alterations, such as adding too much fertilizer. This is an environmentally responsible practice because it prevents needless contamination of water resources.
Testing the pH (acidity or alkalinity) of the sample is relatively easy with a pH testing kit avaiable from most nurseries and some hardware store. Alkaline soil can be adjusted by adding sulfur or compost. Soil that is too acid can be corrected by adding lime.
Soil testing services are offered by many state cooperative extension services and commercial laboratories. If possible, you should use a local service, as they understand conditions in your part of the country. Different levels of testing are available. A basic or routine soil test will test for pH (acidity or alkalinity), extractable phosphorus, potassium, calcium, magnesium and zinc, and cation (positively charged ion) exchange capacity (which affects nutrient retention in the soil). It may also test for minor nutrients such as iron, manganese, copper, zinc, boron, molybdenum, chlorine, and aluminum. A value for nitrogen may also be provided, but it is not particularly useful as nitrogen content can change very rapidly in any garden plot. The laboratory may also provide you with information on the physical properties of your soil, such as particle size, aggregate stability, and organic matter. This will help you to determine whether you need to amend your soil with sand or grit or more than the usual amount of compost. The service should also provide you with suggestions on how to fix any problems.
Most states will have a state university or its exension service that will offer testing for a small fee. Commercial loboratories are also available. In the New York the following services are avaiable -
Cornell Nutrient Analysis Laboratory
G01 Bradfield Hall
Ithaca, NY 14853
Environmental Sciences Analytical Center at Brooklyn College
718-951-5000, ext. 2647
5135 Ingersoll Hall
2900 Bedford Avenue
Brooklyn, NY 11210
For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service