Urban dirt can have higher-than-healthy concentrations of lead, arsenic and other toxic metals that accumulate over time. Soil testing -- whether for pH, salinity or heavy metals -- can be a good idea for anyone who intends to grow edibles or who simply wants to give any type of plant a good start.
We sent our soil samples to two laboratories: Wallace Laboratories ($65 per test) in El Segundo, (310) 615-0116, www.bettersoils.com; and EarthCo ($20 to $100 per test) in St. Louis, (314) 994-2167, www.drgoodearth.com.
You can learn more about heavy-metal content in garden products by visiting the Assn. of American Plant Food Control Officials' website, www.aapfco.org/metals.htm.
-- Susan Carpenter