This is a re-post from a blog I wrote for The Delaware Center for Horticulture last May. I thought it was still relevant to this growing season.
Recently, (if May 14th constitutes “recent” in the world of news) The New York Times ran an article about the dangers of lead in urban gardens. This has been a topic up for discussion around DCH lately.
My co-worker and I both live in Philadelphia and we spend a fair amount of time planning out our little patches of sustainable living within our West Philadelphia community. While I just fantasize about fancy chickens and bountiful yields, he is actually working towards achieving these goals. (See the evidence below)
This spring he planted some edibles in the soil outside his home which, while he admitted was not ideal, at least seemed like an innocuous enough endeavor since he isn’t pregnant and is a good 40 years away from receiving AARP. However, the more we’ve talked about it, the more concern he has for the wisdom of this decision.
The numbers on how much lead in the soil can be deemed “safe” varies from state to state and from country to country. In the Netherlands, for instance, 40 p.p.m. is considered an unacceptable amount to live amidst. In Minneapolis 100 p.p.m. is considered hazardous. Federally, the EPA encourages remediation if 400 p.p.p.m is present and if children will be playing around the area (remediation is suggested at levels of 1000 p.p.m. if children are not a part of the equation).*
But these are just levels to be concerned about if you live near the contaminated soil. To garden in, even small traces of lead can be considered hazardous especially when growing root crops like potatoes, radishes, or carrots, as these have a greater likelihood of drawing up lead.
My friend and I have been discussing some possibilities for negating his untimely demise. Ideally, he would grow in containers, but this seems pretty cost prohibitive. So, we’ve been discussing the pros and cons of phytoremediation, that is, using certain lead-leaching crops like spinach or mustard seed to draw up the contaminant and then disposing of these plants as hazardous material. This is a cost effective way of remediating the soil. However, in order to truly reduce lead levels, lead-leaching crops should be planted for at least two or three growing seasons prior to planting produce you hope to consume, which as a renter, seems like a lot of work for a temporary place.
So what’s an idealistic young Philadelphian supposed to do? Well, he is going to get his soil tested. In the meantime he has put down enough lime to neutralize battery acid, is adding compost to his growing space, and is focusing on planting fruiting crops like tomatoes, squash, eggplant, and beans because they don’t accumulate lead as readily. Other than that he’s keeping his fingers crossed and doesn’t plan on getting pregnant anytime soon.
* Stats taken from The New York Times article “Lead is a Concern for Urban Gardens.” See link above!