The Homegrown Mailbox: How and Where Do I Get My Soil Tested?
...a lab is much more accurate. To find a lab in the US, the best place to start is with your local Cooperative Extension Service. Find yours via this link. Some offer free or low cost soil testing. Here in Los Angeles the Extension Service does not offer testing, but they were nice enough to provide a list of local labs. The lab I talked to, Wallace Laboratories, offered tests at $75 a sample–see their price list for specifics. Before you send a sa...