The Homegrown Mailbox: How and Where Do I Get My Soil Tested?

When you write a book you get questions. In our case, due to the sinking economy in California, they are delivered by Kevin Costner on horseback rather than by email or regular federal postal trucks. No problem, we like questions. A caveat here: like Nancy Klehm, the Green Roof Growers and Black Swan author Nassim Taleb, we prefer the term “practitioner” to describe what we do as opposed to “expert”. We favor experience over speculatifyin’ and make no claims to accuracy. But, we’re happy to take the letters from Kevin, the horse poop for compost and try our best. Here’s one question we get a lot:

Q: Y’all know where I can get my soil tested? I’ve started HUGE garden in my side yard and it just occurred to me that it is where people used to park their cars. I’m concerned about Oil or other pollutants from the cars that might still be in the soil. Any experience with this? Can I test without it costing an arm and leg?

J.R., Los Angeles

A: See my updated response here. [Note update at bottom of this post!] There’s basically two groups of things to test for: contaminants and soil nutrient levels. There are cheap home test kits, but sending samples to a lab is much more accurate. To find a lab in the US, the best place to start is with your local Cooperative Extension Service. Find yours via this link. Some offer free or low cost soil testing.

Here in Los Angeles the Extension Service does not offer testing, but they were nice enough to provide a list of local labs. The lab I talked to, Wallace Laboratories, offered tests at $75 a sample–see their price list for specifics. Before you send a sample talk to the lab to find out what they test for and how much they charge for phone consultation in interpreting the results. If you’re worried about contaminants make sure to describe your situation.

Sampling is a DIY project. You put the soil in a bag and send it off to the lab (they’ll tell you how to dig for the sample and how much to send). You’ll probably need to do several samples since different parts of the yard might have different problems.

In the end I cheaped out and went with Peaceful Valley’s soil testing service for $29.99. No contaminant testing, but the results did tell me that I’m very low in nitrogen, with a soil ph that’s slightly alkaline. They charge for phone consultation, but I was able to interpret the results myself with their slightly overpriced booklet that you can order along with the test.

Another approach, especially if you live in an old house like ours, is to assume that your soil is contaminated, skip the test, and grow things in raised beds, containers or stick to ornamentals. You could also try bioremediation: each season plant a cover crop, let it grow, and then pull it up and dispose of it. Test the soil until it comes out clean. This works well, but it can take many years to get all the contaminants out.

For those of you in Los Angeles, our local Extension Service agent Yvonne Savio kindly sent me the following list of labs with comments.

Biological Urban Gardening Service
PO Box 76
Citrus Heights, CA 95611
(916) 726-5377
URL: www.organiclandscape.com
Email: [email protected]
Organic recommendations, very user-friendly
Owner Steve Zien and I co-author “Organic Matters” organic gardening column in Sacramento Bee for 20 years.

Wallace Laboratories
365 Coral Circle
El Segundo, CA 90245
(310) 615-0116
www.bettersoils.com
Test results very scientific
No recommendations

Soil and Plant Laboratory, Inc.
1594 N. Main Street
Orange, CA
(714) 282-8777

FGL Environmental
853 Corporation Street
Santa Paula, CA
(805) 525-3824

USDA Natural Resources Conservation Service
44811 N. Date Avenue
Lancaster, CA 93534-3136
(661) 945-2604

Here’s a dirt cheap (pun intended) test for soil ph that you can do yourself.

UPDATE: 7/7/09: Visiting journalist Michael Tortorello tipped us off to the University of Minnesota’s soil testing lab will test out of state samples for their regular (low) fee. It’s much cheaper than the services listed above. Their submission forms are located here.

Least Favorite Plant: Yellow Oleander (Thevetia peruviana)


Thumbing through a book of toxic and hallucinogenic plants, I finally manged to i.d. the neighbor’s shrub that looms over the staircase to our front door. The popular name given for this plant in the book was “suicide tree”, so named for its use in Sri Lanka, though I’ve found other plants with this same moniker. The scientific name is Thevetia peruviana, and it’s also known as “lucky nut” (can we change that to unlucky nut please?), Be Still Tree (presumably because you’ll be still if you eat any of it), and yellow oleander (it’s a relative of Southern California’s favorite freeway landscaping flower). I was able to dig up a research study on what the authors described as an “epidemic” of yellow oleander poisoning in Sri Lanka,

“Accidental poisonings occur throughout the tropics, particularly in children. Adults have died after consuming oleander leaves in herbal teas. However, deliberate ingestion of yellow oleander seeds has recently become a popular method of self harm in northern Sri Lanka. There are thousands of cases each year, with a case fatality rate of at least 10%. Around 40% require specialised management and are transferred from secondary hospitals across the north to the Institute of Cardiology in Colombo”

Native to central and south America Thevetia peruviana made its way to Sri Lanka only recently, with the suicides starting up within the last 25 years, according to an article in Bio-Medicine. Apparently news accounts of suicides have fueled its use. The Bio-Medicine article describes a typical incident, “I remember one girl said her mother wanted her to get up and do the shopping. She said no, her mother scolded her and she took a yellow oleander seed.”

A semi-popular landscaping plant, it grows without any water or care here in Los Angeles, though a hard frost would kill it. The elderly neighbor who used to live next door told me that she brought it with her from Mexico. I’ve seen it growing in vacant lots and by the freeway, so it seems to be able to spread on its own. So why put it on the least favorite plant list? It’s neither beautiful nor useful (unless you want to kill someone or hate shopping) nor does it seem to provide habitat or forage for beneficial wildlife. Why plant something that can accidentally poison a toddler?

Welcome to the Summer Fruit Season

Homegrown Neighbor here again. I just picked the first peaches of the summer from a tree in my backyard. They are an early variety called Florida Prince. One was so ripe it immediately started oozing fresh peach juice onto my hand which I readily licked off. It was intensely sweet and full of peach flavor. The peaches all have the most wonderful aroma. Grocery store fruit never has a smell that intense and lovely. Yesterday I ate my first plum of the season as well, a variety called Beauty. It was super sweet and delicious. I am very happy to begin the summer fruit season. I will continue to gorge myself on these sweet treats while they are at their peak over the next few months. And now for the shameless plugs- I’ll be at the Old L.A. Farmer’s Market in Highland Park this afternoon selling veggie seedlings and fruit trees. So come and visit and pick up your very own peach tree and some growing tips. And did you know fruit trees are excellent for irrigating with greywater? Learn how you can irrigate your home orchard with your old laundry water at the greywater workshop tomorrow night with my Homegrown neighbors. Soon you will have an abundant and water-wise garden.

Wonderful Worms

 I’ve been composting with worms for many years now and I am continually impressed by how good they are at what they do- eat our garbage. 

For those who want to start a worm bin of their own you can either buy a bin or make your own. I must say the black, stacking bins made from recycled plastic work very well. They are well designed to allow for a lot of waste in a small footprint and provide good drainage, which is absolutely key for worms. I’ve also made my own bin and I’ll write about that in a separate post. Target has also come out with a fancy worm bin they call the MIO(I’m not sure how to make the link work so you’ll just have to look it up) . I’m incredibly jealous because I wanted to be the first to come out with a snazzy, hip worm compost bin. The Target bin is cute but unlike other prefab bins it is not made from recycled plastic. I still kind of want one. 
Mr. Homegrown has encouraged me to share my failures because apparently readers of this blog love to hear about projects gone awry. I’ve only had one problem with worms but it was a doozy. I had been composting with worms for several years without a glitch when I got overly enthusiastic and threw everything off. There is a local juice bar that doesn’t compost. All that lovely, ground up juicing waste just ends up in the trash. So I decided to take home a big bag- maybe twenty pounds of ground up carrots, wheatgrass, apples, kale and whatever for the worms. I spread it out as a layer in one of the bins. Several days later I noticed flies. I opened the bin and there were all of these hideous larvae crawling around. Now I love worms, but larvae are just gross. They were some kind of fly larvae. I screamed and jumped up and down shrieking for about 5 minutes. I closed the bin and decided to wait. Composting is all about balance. I knew I had thrown off the equilibrium of my worm composting system. After about five days of just letting the bin do its thing I started by slowly adding just my morning coffee grounds. I put down a thick layer of shredded newspaper to keep any more flies from getting in. After about two weeks I had restored the balance, the larvae were gone and the worms and I have lived happily ever after.