To determine the exact components of your soil, you can do any of the following three things:
You can purchase a soil test kit at many retail garden centers and do the testing yourself
Soil test kits range in cost from $10 to $50 for multiple tests. A Technology & Product Report from the American Society of Horticultural Science assessed the accuracy of commercially available soil test kits, as compared to test results from an analytical laboratory:
#1. La Motte Soil Test Kit (La Motte Co., Chesteron, MD) 94%
#2. Rapidtest® (Luster Leaf Products, Woodstock, IL) 92%
#3. Quick Soiltest (Hanna, Woonsocket, RI) 64%
Source: HortTechnology 17:358-362 (2007)
Or you can send a soil sample to a testing laboratory
Testing laboratories charge for soil analysis. We suggest that you call the selected laboratory prior to submitting samples. Quite often samples must be taken, packaged, and sent in a particular manner in order to obtain the best possible diagnosis. Soil testing laboratories in Southern California are:
1. Associated Labs, Orange (714-771-6900)
2. Soil and Plant Laboratory, Inc., Orange (714-282-8777)
3. Wallace Laboratories, El Segundo (800-473-3699)
4. The PACE Turfgrass Research facility in Oceanside (760-272-9897) maintains a list of soil analytical laboratories.
Or you can visit Orange County Farm Supply in Orange and drop off a sample; be sure to call them at (714) 978-6500 first to find out how to take a sample.