Concern about soil contamination for vegetable garden

General    Lausanne, Switzerland

I just moved into a new home (San Francisco Bay Area) which has a nice, sizable backyard for a vegetable garden.

The house was not looked after well by the previous tenants, and I'm concerned about what might be in the ground. I know I can test for pH, nutrients and things like that, but what about toxins (lead etc.) - do I need to be concerned about that? Or should I just play it safe and do raised beds?

I know I can in principle send a soil sample to a lab (e.f. http://homeguides.sfgate.com/soil-con...) - is this a sensible thing to do, or am I being overly concerned here?

Any guidance / experiences appreciated.

Posted by: deactivated (25 points) deactivated
Posted: February 25, 2014


If it were me, Marcel, I would definitely test for lead, especially if the home is located in an older neighborhood of pre-1970s homes on a heavily-trafficked road. Soils in such areas often contain lead from paint chips and auto emissions.

As this little fact sheet http://bit.ly/1ckGa6t notes, the danger is less from eating garden crops grown in such soils than from directly ingesting contaminated soil particles. Make sure you scrub and rinse your veggies well.

You can still garden in lead-contaminated areas by in raised beds filled with "manufactured" soil (potting mix, composts, perhaps some uncontaminated mineral soil).

Posted by: Peg Boyles (2 points) Peg Boyles
Posted: February 25, 2014

I've read about but not tried a quick-and-dirty method to assess your soil. Plant some seeds in your soil (and in potting soil as a control) and observe their growth. Do the seeds germinate at a good rate? Do the plants look normal, or are they deformed? The usual seed recommended is radish seed, but for me, kale germinates faster.

Adding a good amount of compost will bind any heavy metals in the soil.

Rufus Chaney has several papers on urban soils and heavy metals. Here's one.

Posted by: Tanya in the Garden (128 points) Tanya in the Garden
Posted: March 1, 2014

Wayne Clingman commented,
Yes, I do a Soil test they are cheep and should help a lot good for peace of mind.
about 5 years ago.

Marcel --
After you absorb the information in Tanya's link, look for Mizuma and soil contamination. We moved into an old section of Tacoma (my wooden house is over 100 years old) about 8 years ago. We are near a Superfund site, but not in the impact zone.

Since my grandchildren would be eating from the garden and playing in the yard, i called the county health department for advice. They sent an inspector who checked the soil: very close to one corner of the house, and in the two places where i expected to set up my garden -- adding subsamples to the primary sampling areas. Only the corner near the house tested positive for heavy metals.

We *assumed* it would be from lead paint on the house, so the inspector returned and checked all around the house. The tests showed no other heavy metal concentrations. Later i learned the concentration at that corner was probably because a previous owner used to repair his car there frequently.

Before planting anything anywhere, i started looking for remediation possibilities and learned that Mizuma is one of the best plants for phytoremediation. In a quick & dirty search, the only paper i can find on it is at http://academic.research.microsoft.co....

In the end, we planted roses on that corner and my vegetables in raised beds. The benefits of raised beds are too numerous to count, and i won't garden any other way now! Good luck with your urban garden.

Posted by: PFletch (2 points) PFletch
Posted: May 22, 2014

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