Testing the Lead Testers

Varian ICP-MS from Wikipedia

Dear readers,

Excuses for a technical post here, but we need your scientific expertise. If you have experience in soil laboratory testing techniques, or know someone who does, please send us an email at [email protected] or leave a comment. We’re attempting to reconcile slightly different lead results from three different labs and I’d like to be able to write about soil testing methods. Two of the labs we sent samples off to (UMass and Timberleaf Soil Testing) use inductively coupled plasma mass spectrometry (ICP) to test for lead. Wallace labs uses an extractant, AB-DTPA (ammonium bicarbonate Diethylene Triamine Pentaacetic acid).

Here’s how Wallace described their lead testing techinique,

We use AB-DTPA (ammonium bicarbonate Diethylene Triamine Pentaacetic acid).

It is a gentle extractant and it mimics roots in extracting minerals from the soil. Most often environmental tests are made with boiling acids which are more aggressive than roots. The AB-DTPA method is a standard testing method of the Soil Science Society of America. It is called the universal extractant. It measures the bioavailable or plant available minerals which is expected to be adsorbed by plants. Most of the background heavy metals are occluded and are unavailable to plants. Our testing does not see the occluded metals.

Total lead is approximately 10 times higher than our AB-DTPA measured lead. We recommend that AB-DTPA lead be less than 30 parts per million for home production of edible produce.

UMass says,

We use a modified Morgan solution (dilute glacial acetic acid and ammonium hydroxide) to measure extractable lead (using ICP).  Total Estimated Lead is calculated using a correlation established during a study performed here at UMass that compared total digestion levels to extractable levels using 300-400 soils.

I divided one soil sample into three parts and sent a portion to three labs. While all three labs indicated the presence of above natural levels of lead, there were enough differences between the tests to warrant a closer look at the techniques. Your assistance would be greatly appreciated and we’ll share what we find out.

Food Preservation Resources

Due to a popular post on making prickly pear jelly, we get a lot of emails asking for advice on canning. So I thought I’d list three favorite food preservation resources.

I like to go to respected sources when canning for reasons of both safety and reliability. While botulism is fairly rare, it’s a highly unpleasant way to pass this vale of tears. But beyond the safety issue, if I’m going to go through the work of canning, I want to know that the recipe is going to work. There are few things more frustrating than a big batch of jam or jelly that doesn’t set. Yes, you can call it “syrup” but it’s still a big blow to the ego. 

My three favorite resources are the National Center for Home Food Preservation which has recipes for all kinds of food from fruit to meat, the Ball Complete Book of Home Preserving and Ball’s website. All of the recipes in these two websites and book follow USDA guidelines.

The reason I came up with a prickly pear recipe is that I couldn’t find any other ones that worked. But if I were canning something like, say, peaches I’d go with one of the above authorities. If you have a favorite food preservation resource leave a comment.

Gifts for the Holidays Food Crafting Workshop

One way to avoid the consumerism of the holiday season is to make your own gifts. And if you live in our hometown you can learn how to make edible gifts while supporting the recently revived Los Angeles Master Food Preserver program. From their announcement:

Join the Master Food Preservers of Los Angeles County and Homegirl Cafe for a special workshop and fundraiser on Sunday December 4th from 1 to 4 pm.

Master Food Preservers Ernest Miller, Felicia Friesema, Joseph Shuldiner, Amy Goldman, Roshni Divate and Craig Ruggless.

Learn how to make truly unique and special home crafted food gifts for the holiday season! Topic include food ornaments, elegant liqueurs, gourmet mustards, seasonal spiced jams and candied fruits.

Guests will take home samples and recipes, knowledge and a healthy dose of holiday cheer.

Proceeds benefit the Master Food Preserver program, a volunteer community education group of the University of California Cooperative Extension.

The cost is $45 and you can get your reservation here.

The workshop will take place at the Homegirl Cafe which is located at: 130 West Bruno Street, Los Angeles 90012. 

Two Vegetable Gardening Commandments

Two of our vegetable beds looking kinda shabby.

I spent the Thanksgiving weekend up on the vegetable gardening equivalent of Mount Sinai receiving a set of revelations. Someday I’ll have Mrs. Homegrown transcribe the complete stone tablets (urbanite rather than stone, technically) I received in their entirety. In the meantime, I’ll share two of the commandments:

1. Thou shalt not have more vegetable beds than thou canst maintain in a worthy condition.

We’ve already reduced the amount of vegetable space in our garden and replaced it with native perennials. I’m considering cutting more vegetable space. Having a lot of poorly maintained vegetable beds sends out a big invitation to the sorts of insect visitors we don’t want in our gardens. Better to have one well maintained and productive vegetable bed than ten poorly maintained beds. And right now I’ve got a few less than optimal beds.

Light row cover stretched over hoops protects the bed from cabbage moths

2. Thou shalt secure thy vegetable beds with bird netting or row cover material even if thou thinkest “I’ll get lucky this time.”

I do this every year even though I know that if I leave a newly planted bed unprotected it will be visited by a clumsy skunk or a cat looking for a place to poop. I hate bird netting–it inevitably gets tangled and is a pain to work with–but the fact is that if I don’t use it I don’t get any vegetables. And, if I plant any brassicas at this time of the year without first covering them with row cover material, they will get munched to the ground by cabbage leaf caterpillars.  I’ve found that once the plants gets established I can pull off the row cover or bird netting and enjoy a season of un-munched veggies.

Kelly Speaketh on this Issue:

Erik seems to need to get this off his chest–he gets dramatic when garden disasters occur, and we’ve been hard hit by the skunk and cutworm brigades this week– but I’d say he’s being way too hard on himself.

First and foremost, we learned about the possibly high levels of lead in our soil, just when we were at the critical transition stage between the summer and winter garden.The whole yard became off-limits at that point. We just let things go until we knew what we were going to do–and we’re still figuring that out. So yup, the two beds in the top pic look like crap, because they are completely untended beds–beds that have been waiting around for us to figure things out. They don’t look that way because we have too many beds.

We’ve had fallow beds, and cover cropped beds, beds gone a little wild, and beds full of things going to seed, but I’ve never thought our beds poorly maintained–except in the last two months. So I think Erik just needs a glass of scotch or something tonight.
Just to be factual, we have four vegetable beds. We used to have more ground space where we could plant food, which helped with rotation, but we’ll be doing all our veg growing in our four raised beds from now on out, and dedicating the ground space to natives and other perennials. We had planned to do this prior to the lead thing, coincidentally–to save labor. We figure four beds is plenty for the two of us.

As to the lead thing (that’s what I call it–“the lead thing”), we are still getting conflicting tests from different services. One testing service even insists we don’t have a problem at all! Until we sort this out, we’ve decided to “Keep Calm and Carry On” and plant in raised beds.

As to Commandment #2: I agree entirely! The beds must be protected. Otherwise husbands have breakdowns.

Netafim Tiran, a Greywater Dripline

In a lecture I heard recently, Leigh Jerrard of the Greywater Corp mentioned an intriguing product from Australia: a dripline compatible with greywater. Now, if you tried to push gunky greywater through conventional dripline it would clog in seconds. According to the manufacturer, Netafim Tiran Greywater Dripline gets around this problem because,

Each dripper has its own mini filter. When a contaminant attempts to enter the emmitter, it is rejected by the emitter and simply remains in the tube. The irrigation system should be flushed once a year, however anecdotal evidence indicates that flushing may only be required every 5 years.

100 meters of Netafim costs 100 Australian dollars excluding tax, or about .30 USD a foot. Not a bad price if it performs as advertised. Some quick Googling failed to turn up a US distributor. Root Simple reader Rachel wrote to point out Netafim’s distributor locatoer: http://www.netafimusa.com/wastewater/support/locator.

To use Netafim you need to add a filter as you do with every drip system. I could see this product working nicely with Art Ludwig’s Laundry to Landscape system.

If any of you have worked with Netafim, leave a comment.

The Holiday Gift Truce

One of the traditions my family has experimented with in the past few years is the holiday gift truce. At Thanksgiving we agree to terms. In the past we’ve exchanged names and given one gift per person or we’ve just agreed to not do any gift giving or shopping (kids are exempt). Though we haven’t tried it, another option would be to contribute to a favorite charity, say Heifer International, in lieu of gifts.

Economics professor Joel Waldfogel has studied the inefficiencies of gift giving and calls Christmas, “an orgy of value destruction.” The problem? When it comes to gift giving we’re not very good at guessing what people actually want. In a Bloomberg article Waldfogel says, “People value the items they receive as gifts 20 percent less per dollar spent than the items they purchase for themselves. These are items that are not well-suited for their tastes.”

Particularly in challenging economic times it’s hard to justify this orgy of value destruction, not to mention the stress and time spent in mall parking lots. I’m interested in how readers of this blog navigate the holiday season. Do you make your own gifts? Do you think gift giving is important? Do you give cash or savings bonds? Or do you avoid gift giving altogether?

Meet the Gophinator

The Gophinator

Thankfully, we don’t have gophers, but dealing with them is one of the first questions we get when teaching vegetable gardening classes.  You can use raised beds lined with hardware cloth. But, other than target practice (a no-no in urban areas), most people I know with gopher problems end up using traps or zealous cats.

Several sources have told me about the Cadillac of gopher traps, the aptly named “Gophinator”. Scott Kleinrock of the Huntington Ranch is one of those Gophinator fans, who stressed avoiding the cheap traps available at big box stores. The Gophinator is sturdy, easy to set and made out of stainless steel that lasts much longer than cheaper traps.

To use it you need to dig around and find the main subway line the gophers ride. Scott hooks up a wire and a stake to the traps to remember where they are placed.

The Gophinator is manufactured by Trapline products and you can order one and view some instructional videos here.

How do you deal with gophers? Leave some comments!