A note about soil testing: if your plants are growing well, you may not have to worry about it. However, from the Master Gardener Handbook 2nd Ed.: "because most nutritional disorders of plants are difficult to diagnose from visual symptoms alone, tissue and soil analysis are often needed as well. In some instances, plants may not show symptoms of nutritional deficiencies until severe stress has occurred."
Soil Testing Options
The UC Master Gardeners do not offer a soil testing service. If you're interested in learning more about the composition of your soil, you should contact a commercial laboratory. Inexpensive do-it-yourself soil test kits are available but they are not very accurate. Commercial analytical labs like those listed below are more expensive but provide more accurate results. Many universities have less expensive testing laboratories that can be used even if they are located out of state.
Testing services may include the following. Please contact the lab for specific services.
- Soil testing for pH, salts, nutrients, trace elements
- Water testing for biological and mineral components
- Plant pathology testing for diseases and nutrient deficiencies.
This list of labs is not all-inclusive and is provided as a convenience to the public without implying endorsement of any specific business.
- Caltest Analytical Lab, Napa
- CERCO Analytical, Inc., Pleasanton
- Control Laboratories, Watsonville
- Perry Laboratory, Watsonville
- Soil and Plant Nutrient Testing Lab, University of Massachusetts, Amherst
- Waypoint Analytical, San Jose
UCCE Sonoma has a more comprehensive listing of Northern California laboratories.