Soil testing can provide information on your soil’s texture, pH, salinity and the level of essential plant nutrients and fertility. This information will be especially helpful if you are starting a new garden. Soil testing may also help you learn why plants are not growing well in an existing garden.
A soil test is not always necessary, and it will not tell you if poor plant growth results from other causes: pests, diseases, improper irrigation, or poor cultural practices (e.g., planting at the wrong time of year). One of the most useful soil tests is the measurement of soil pH. The test will tell you if your soil is too alkaline or acidic and if corrective measures are needed. A lab can measure soil pH for you or you can do it yourself. A simple pH meter and test kit are available at local nurseries or from mail order companies. Contact a local Agricultural Testing Lab (scroll down to see the map) or call the UC Cooperative Extension office in San Diego (858-822-7711) for a list of local labs. Check with the lab you intend to use to learn how to best collect the soil sample, and ask if they provide a report to help you interpret the result. Also ask if they provide recommendations on how to correct soil problems.