Lots of news about this. Just do a search for "lead" and "raised beds". The standard approach is raised beds, but it was found a few years ago in a research paper that raised beds over lead-contaminated soil eventually get lead-contaminated.

http://commonhealth.legacy.wbur.org/2010/11/lead-in-urban-garden

The lead is somehow mobile in the soil. A fabric barrier is a good strategy to keep the lead in it's place, however. There are lots of lead mitigation strategies. Crops to plant that don't take up lead efficiently, and keeping the soil pH high.

If you are worried about soil contamination in that way then you could have a few soil tests done specifically for that. Vast majority of plants will use only the top 6-12 inches of soil but deeper/taller beds are more ergonomic. There are some kinds of bioremediation crops although that's a little different than setting up raised beds.

http://www.resilience.org/stories/2014-08-11/using-plants-to-clean-contaminated-soil/

https://land8.com/5-best-plants-for-phytoremediation/

https://remineralize.org/2007/12/sea-90-2/

Agree with the above that I wouldn't go to a lot of extra work and expense without first knowing for fact that my soil was actually "contaminated". You know what they say about assumptions. ;-) The clay soil could be more of a problem than any lead contamination is.

Then even if a soil test confirms higher than normal lead content (400 ppm) you have to take into consideration, as gardengal mentioned, the natural filtration ability of the plants themselves and the effects of good garden hygiene.

That said if you wish to do the work and expense of a raised bed then you have to assume the plant roots of many things - especially tap root vegetables - will reach down into the soil native even if the bed is 18-24" deep. As well as the fact that the lead will migrate into whatever you fill the bed with.

One study I have read out of Oregon State Extension indicates the lead tends to localize in the top 2 inches of the soil, to have the highest levels of contamination, so soil stripping of the top few inches can often eliminate areas with abnormally high levels.

Dave

YAY Glad to hear this! I've just moved into a 1914 home and didn't even think of lead in the soil!

We are planning on planting in ground this year and also have one raised bed.

We'll dig down a few inches in the planting area which will also help with watering. Nancy

Thank you all! This is so helpful. Since we just moved in and I probably need to check on sun/shade patterns before committing to a spot for a raised bed, for this year I think I will just grow things in pots (which were surprisingly productive at my old house) while I explore all of this research.

I will do soil tests, but I'm aware that lead/contaminants probably aren't evenly dispersed, so I'm just acting on the assumption that a densely-settled neighborhood with painted wood houses dating to the turn of the century (not to mention 70 years of leaded-gas vehicles) will have some level of lead in the soil. Interesting point about dust being the real problem, though; contaminants will just blow right into your pots or raised bed, I suppose.

Thanks again; reading all the links now! I love reading about the scientific research so keep it coming if you have more to offer.

I would assume that lead levels would be higher around the edges of old buildings. Most soil likely contains micro amounts of lead and other 'bad' contaminents. The dose or level is the thing.

I never knew about this kind of problem in terms of gardening. Very interesting. You learn something new every day!

Yes, our whole small yard is basically around the edges of old buildings. We are in a semi-urban area ("streetcar suburb" of Boston) and the houses are quite close together. I have elementary-aged kids and I want to teach them about gardening without poisoning them too badly!!

So, lead accumulation in people is dangerous, but the garden toxicity thing gets blown out of proportion a lot of times I think. Blog style articles mention stuff like plastic leaching into the soil, but those materials are inert and are used in all kinds of farming organic and conventional. Worrying about something getting into the soil then your plants taking it up is very different from spraying pest/herbicide right on your food several times, for example. Gardening is a great hobby and I think chances are your garden won't have 1/2 the level of harmful stuff as most big farms.

A lot of lead deposits in the soil are from car exhaust, from the era of leaded gas. I agree that lead from old paint is more likely to be around the periphery of houses, where old paint has been stripped, than in beds further removed. It's well understood in my area that beds along roads have higher lead content than beds away from roads. I've never heard of a roadside bed that is in violation of USDA limits, but elevated lead levels on roadsides are common.

It's true that plants end up with lead concentration that is lower than the soil they are growing in, but if your soil lead level is very high, it can be worth some worry. If you're concerned, do yourself a favor and get a test.

I'm not sure how much you can trust them, but DIY lead-test kits are cheap, for a number of separate tests.

so did get a soil test and what were the results.

This is all very interesting. I too have my garden situated along my 1910 bungalow in downtown Atlanta. I have part of it in the ally way and the other part in my front yard. Another thing to consider is what they used to spray in the ally ways to keep the weeds down so the carriages could pass through. They used some toxic stuff back then.

It wouldn't still be hanging around after all these years :-)) Even recent herbicidal sprayings will dissipate with time.

War garden: Right now my soil is under a few inches of snow with 6 more inches on the way tonight. I'll get to testing it once things thaw out a bit and will post results here!

I wouldn't agree Gardengal48. Look at the Belt Line construction through Atlanta. They required the EPA to come and clean up prior to allowing pedestrians due to the spraying. They sprayed the railroad corridors and various ally-ways/road ways with some very toxic stuff. https://beltline.org/progress/progress/environmental-progress/initiatives/brownfield-remediation/.  My brother is one of the architects working there. I forget the chemical that was used, but it was similar to agent orange.

There was nothing in that link to indicate what exactly they were instigating remediation for. Contamination by various chemicals is one thing - it could be heavy metals, mine tailings, creosote, smokestack emissions, etc. Contamination from pesticides is something else all together. Organochlorines can be very long lasting pesticides, but they have been banned in the US since the 70's. And they were used for insect control, so their use along railroad right of way and in alleys would have been minimal, if at all. About the only herbicide with significant persistence is Agent Orange......and it was never used here in the US.

lalala "i want to teach them about gardening without poisoning them too badly!!" LOL

I don’t think you can compare rail lines with the average urban back yard. Rail lines were and continue to be a toxic disaster. Keeping thousands of miles of track clear requires harsh measures or a lot of manual labour, which is impossibly costly.