What We’re Going To Do About That Lead

White sage, yarrow, rosemary and aloe vera–the kind of plants we’ll be planting more of.

Let’s assume that we have a lead problem in our backyard. That’s a big assumption at this point because we now have two very conflicting test results. But, for the sake of an argument, let’s say the first alarming test is true, what are we going to do about it?

These are the options:
  • Radical remediation: Remove all the soil in the yard and replace with new soil.
  • Cover the contaminated soil so that it doesn’t give off dust, and so people can’t come in direct contact with it, e.g. lay sod, cover the yard with concrete or decking, or lay down a thick layer of mulch.
  • Grow ornamental plants only
  • Grow all food in raised beds
  • Attempt phytoremediation (grow plants that uptake lead, pull them and send them to the dump)
  • Move

It turns out we were already doing some of these things, so we’re just going to keep on going as we were with a few changes. Our yard has always been covered in a thick layer of mulch and we do most of our growing in raised beds. We will stop growing edibles directly in the ground. We’d already planned to redesign the yard to include lots more native and Mediterranean flowering plants. These we can’t eat, but will secure the soil and provide food and shelter for lots of beneficial insects who will aid our food crops. We’re really happy that we’ve always mulched, because it has helped keep the (potentially) contaminated soil in place and has increased bio-activity as the mulch decomposes.

This raised be would have to be raised higher.

Most plants don’t take up much lead, it turns out. Our soil phosphate levels are high and the pH is moderate, two factors that further decrease the ability of plants to access lead. The main health concern comes from directly ingesting dirt, and that can be avoided by washing and peeling vegetables and fruits. The recommended wash for lead is a splash of vinegar in water (1 tsp per 1 1/2 qts water).
I’d be more concerned if we had kids and they played in the backyard. Little kids, of course, are most at risk because they tend to ingest dirt during play. If it turns out there is a lead problem at our house, I plan on knocking on the doors of my neighbors with kids, warning them about what I’ve found and offer to help them do a lead test. In our public speaking and teaching we emphasize the importance of getting a soil test and we’ll keep doing this.
Phytoremediation, the process of growing plants that concentrate lead, pulling them up every year and disposing of them holds a lot of promise. Unfortunately I don’t see how it would be practical in a residential situation. If the contamination is widespread I’d have to remove every plant and tree and grow nothing but, let’s say, sunflowers, for perhaps several decades. (Sunflowers pull up lots of lead.) In short, phytoremdiation is an intense, long term process.
I think the most important thing we can do is spread the message that soil is a sacred resource–something that we should not foul up in the first place. More and more we’re coming to realize that soil is everything–our future and our well being is inextricably tied to its health. We know how to treat it right. We’re just not doing it. We know what toxins are, and we’ve know it for a long time. For instance, lead has been known to be a problem for thousand of years. Benjamin Franklin, in a letter dated July 31, 1786, comments on lead poisonings caused by contaminated rum, and the lack of concern about this problem: “You will observe with concern how long a useful truth may be known and exist, before it is generally received and practiced on.”  
You said it, Ben.

Get a Soil Test!

Regular readers have probably already got this message, but right now we can’t repeat it enough. If there’s a lesson with our backyard lead scare , it’s to practice due diligence when beginning a garden –or better yet, when you buy property–and that means getting a soil test from a soil lab. They’re not that expensive, especially when you consider the high cost of remediation, and the well being of your self and your family.

Test soil for both nutrients and heavy metals when:

  • Buying a house or land
  • Starting to grow food in your yard  
  • Are growing food and have never tested
  • Starting a plot in a community garden or a school garden
  • Buying soil in bulk

Property does not have to be on the former site of gas station to be suspect. Lead contamination comes not only from lead paint on older houses, but was also deposited all over urban centers and near busy roads via a constant rain of fine particulates from auto emissions.

    It really is a shame that lead testing is not a standard part of the inspection phase of home-buying, especially as this is a pervasive problem in urban areas.

    Do companies that sell bulk soil test that soil for lead? A few phone calls Darren Butler made to local companies indicate that they don’t. So let the buyer beware here too. Wondering about bagged soils? Susan Carpenter, at the LA Times, tested a bunch and found no problems.  She did find a possible lead link to fish fertilizer, however.

    We’ve used all three of these services. UMass is the cheapest by far, but gives the least analysis. However, if you just want your lead level numbers, that’s not a problem.

    Wallace Laboratories
    UMass Soil Testing Service
    Timberleaf Soil Testing

    In our next lead post we’ll let you know what our plan is. And we know there’s interest in all this, so over the week we’ll talk about remediation, raised beds, what’s dangerous, what’s edible, and more. Fun for all, guaranteed!

    Lead Update

    This week I thought I’d do a series of posts about soil and heavy metals beginning with a few more details about the possible lead contamination situation in our backyard.

    Two weeks ago Darren Butler, who is teaching a vegetable gardening series at our house, led a class project where we took four samples from different locations in the backyard, mixed them together and sent them off to Wallace Laboratories, a local soil testing lab with an international reputation. The results came back showing plant available lead levels at 112 parts per million. Note that “plant available” is different than the total amount of lead in the soil. The total amount would be about ten times higher or 1,120 ppm. According to the University of Minnesota Extension Service,

    Generally, it has been considered safe to use garden produce grown in soils with total lead levels less than 300 ppm. The risk of lead poisoning through the food chain increases as the soil lead level rises above this concentration. Even at soil levels above 300 ppm, most of the risk is from lead contaminated soil or dust deposits on the plants rather than from uptake of lead by the plant.

    If the Wallace Labs report is correct, we’ve got a serious problem. It is possible that, in sampling and averaging multiple locations, we hit a “hot” spot where someone may have dumped paint or paint chips. Clearly, we’ll have to set up a grid of tests to see if the problem is isolated.

    I re-did the first test, trying as best I could to take samples from the same locations and sent this second test off to the less expensive UMass soil testing service. The results came back with substantially lower lead levels: 220 ppm, in the “low” range according to most experts, but still higher than I would like. Except for the soil pH, all the other numbers were completely different.

    The next step will be to test the testing services. I’m going to take one sample and split it into three parts, sending one to Wallace, another to UMass and the third to Timberleaf Soil Testing. I hope that two of the testing services agree on something!

    In subsequent posts I’m going to discuss what we’re going to do, phytoremediation (spoiler alert: I don’t think it’s practical in residential situations), and my issues with the real estate industry.

    This week the Center for Disease Control and Prevention is promoting their National Lead Poisoning Prevention Week. Especially if you have kids, get your soil and the interior of your house tested.

    One Craptacular Week

    It’s been one hell of a week. First we find out, via a soil test, that our backyard may have high levels of lead and zinc. We’ll write a lot more about this once I confirm the results–I’ve sent in another sample to a different lab. And my doctor has agreed to give me a blood test. Whatever the results, I want to help get out the word about this serious issue–ironically, next week is National Lead Poisoning Prevention Week.

    Then yesterday we found out that one of our kittens, Phoebe, has a some sort of serious heart defect. The blogging muses can sometimes leave us at times like this so don’t be surprised if it takes us a few days to get ourselves back together.

    So please hold our dear little kitten in your thoughts and prayers as well as the worldwide need for healing our soils. After all, we all need to eat, and all food whether it be plant or animal based, has its origins in living soil systems.

    SunCalc: A Sun Trajectory Calculator

    In attempting to figure out how to align a garden path with the sunrise of the summer soltice (that’s the way we roll at the the Root Simple compound), I came across a neat Google Maps hack: SunCalc, the creation of Vladimir Agafonkin.

    According to the description on the site,

    SunCalc is a little app that shows sun movement and sunlight phases during the given day at the given location.

    You can see sun positions at sunrise (yellow), specified time (orange) and sunset (red). The thin orange curve is the current sun trajectory, and the yellow area around is the variation of sun trajectories during the year. The closer a point is to the center, the higher is the sun above the horizon. The colors on the time slider above show sunlight coverage during the day.

    I can see SunCalc being useful for laying out a garden, window and solar panel placement, evaluating potential real estate, or for planning your own personal Stonehenge.

    Root Simple and Edendale Farm on ABC-7

    A local ABC affiliate did a nice, short piece on growing food in the city featuring us and our friend David Kahn of Edendale Farm. I’ll note that David runs a real city farm (he sells eggs) while I call what we do simply gardening, as we don’t grow/raise enough to sell.

    It’s good to see vegetable gardening and keeping chickens going mainstream–it’s the bright side of the “great recession”.

    Building With Adobe

    Architect and Root Simple friend Ben Loescher, along with Kurt Gardella, is teaching a class on adobe construction. I’m going to attend the second day, November 6th, and hope to see some of you there. Adobe has a storied past and a promising future in the Southwest U.S., in my opinion. Here’s the info on the class:

    adobeisnotsoftware is pleased to host Kurt Gardella for the first in a series of classes on adobe construction within California. Kurt developed much of the online curriculum for Northern New Mexico College’s adobe program, and has great expertise in both adobe construction and earthen plasters and finishes. Intended as an introduction to adobe construction for individuals and building professionals, the course will give attendees sufficient knowledge to make adobe bricks, build a garden wall, and understand typical building code and detailing challenges that confront adobe building projects in California.

    Advantages and Disadvantages of Adobe Construction
    Soil Selection and Testing
    Making Adobe Bricks
    Water Resistance and Stabilization
    Adobe Forms
    Brick Laying Techniques
    Doors, Windows and Other Openings
    Seismic Design
    Adobe for the Owner/Builder
    Instruction Type:

    This is a hands-on class. Attendees will have the opportunity to get dirty and use tools and equipment typical of adobe construction. Due to the course format, enrollment will be limited to 14 individuals. Children under the age of 14 unfortunately cannot be accommodated. In the unlikely event of inclement weather, instruction will occur indoors.


    Kurt Gardella teaches adobe construction at Northern New Mexico College, is Director of Education for Adobe in Action, and is certified as an earth-building specialist by the German Dachverband Lehm.

    Ben Loescher is a licensed architect, founder of adobeisnotsoftware and principal of golem|la.


    The class will be conducted about 12 miles outside of Joshua Tree National Park in Landers, California, some 40 miles from Palm Springs. Joshua Tree and the surrounding area have a wealth of great hiking, climbing, lodging and food options. Directions to the workshop site will be provided to attendees prior to the class.


    The cost for the two day workshop is $250/person, a reduced rate of $150/person is offered for full-time students with valid ID. Coffee and nibbles will be provided at the beginning of the day; lunch is included. Register here!


    Please do not hesitate to contact Ben at [email protected] or (760) 278-1134 .

    End of Summer Photos

    I’ve got a backlog of random photos that, somehow, never made it into full blown blog posts. Here’s some of those pics starting with our modest passion fruit harvest. Beautiful flowers and tasty fruit.

    Kelly accidentally planted some potatoes amongst her sweet potato patch. We got a few potatoes and some pretty potato flowers.

    My friends Gloria and Steve, who own a small herd of goats, did a goat milk tasting at the Institute of Domestic Technology comparing their backyard milk against a couple of store bought goat milks and some cow milk. Guess what? Fresh goat milk from the backyard is delicious and does not taste “goaty”. Store bought goat milk just doesn’t compare, though the Summer Hill brand at Trader Joes is passable.

    Lastly, two of my favorite things: cats and corded telephones. 

    Best wishes for a happy fall for all Root Simple readers.