Wednesday, June 1, 2011

Part 2: What's in Commercial Compost? Nobody Knows

I drove around town for a week with bad-smelling compost.
Yesterday I wrote about how, under the spell of an overwhelming desire for a Japanese maple, I ended up with a truck full of bad-smelling compost. After several days in which the smell did not dissipate, I asked a gardening friend to come by give a second opinion. That was a first – inviting someone over to smell compost. Meanwhile, I put on my former journalist’s hat and made some calls.

The man from the Orange County agriculture cooperative extension immediately put me at ease by 1) not dismissing me as a crank and 2) saying he, too, is “into smelling dirt.” He said he regularly receives calls from people reporting problems with compost. “There’s really no regulation at all on what goes in and what goes out and what’s being sold as compost,” he said. Waste gets moved all over the world these days, and there’s no testing of what’s in it, he said.

The main problems homeowners report are compost infested with weeds – compost is a common way to get Bermuda grass and nut sedge. Sometimes bad compost turns plants brown. “What occurs when piles are not turned as frequently as the should be is they go anaerobic on the inside. It creates a lot of stinky things, which is not only bad to smell but bad for plants,” he said.

I was somewhat relieved when the cooperative extension man said that it’s not common to find outright contaminants in compost. But, then again, since no one’s required to test compost, how are we to know that?

I had become concerned about toxic compost after doing some research online. In 1999, in Washington State reports surfaced of plant damage due to compost contaminated with the herbicide clopyralid. The state later banned the use of clopyralid in products sold to homeowners. And in Britain in 2008, many gardeners reported vegetables withering after applying manure that turned out to have been contaminated by the herbicide aminopyralid. (There are many reports of contaminated compost - too many to summarize here.)

This compost smelled like cigarette butts.
And I wasn't too pleased about the orange mulch, either.
I was surprised to learn that in my home state of North Carolina, in the last three years gardeners and farmers have reported problems with contaminated horse manure that wound up in compost. Farmers frequently spray powerful broad-leafed herbicides on hayfields, and as even a child knows, what goes in must come out. Horses and cows are fed the hay, the manure is collected and then is sold for use in compost. Some of the herbicides remain in the soil even years after the compost is applied, the cooperative extension man said.

Tomatoes are among the plants most sensitive to residues of these herbicides. So are beans. Great. Aside from herbs, tomatoes and beans are my summer vegetable garden.

By then, I wasn’t feeling too happy about all the compost, both bulk and bagged, that I had spread over my garden in the last eight years. Perhaps bagged compost is safer? I asked. “Bags are another mystery product. You never know what you’re going to get,” he said.

I asked for advice. How can be sure I’m buying a product that I feel safe to use in my organic garden? The extension specialist said he does two things when buying compost:

1) Visit the place where you’re buying the compost from and look at the piles. You want to see that the pile has been turned, that it doesn’t have an odor, and that it doesn’t have weeds growing on it.
2) Take a cup of soil from the pile, bring it home and do a bioassay test. Plant radish seeds or grass seeds (something that’s going to germinate in a few days). Wait to see if they come up and when they do, how they grow.

The backyard composter.
“Aside from that, it’s about impossible to determine if you’ve got contaminants in your compost,” he said. I tried to imagine myself, every time I wanted compost, driving an hour and a half to the company that makes most of the compost sold in our area, inspecting the piles, taking a cup of soil, planting seeds and waiting for them to grow. And by the time the seeds were up, wouldn’t a different batch of compost be available for sale?

I made a quick decision. From now on, the only compost that I’m putting on my garden is that from my own pile, where I can control what goes in and know what comes out.

P.S. At the suggestion of my gardening friend, I donated the compost to the gardens of the group home at which I volunteer. I still don’t feel quite right about it, but she said they were  happy to have it.


For information on how herbicides in soil affect tomato plants, click here.

For an excellent overview from North Carolina State University on the problem of herbicide carryover in compost, click here.

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15 comments :

linniew said...

Once I tried the very inexpensive "organic" compost from the county recycling place and found all kinds of plastic and other non-garden-like stuff, quite frightening. Compost on!

Donna said...

How scary is this to have nasty chemicals in the compost....I get more discouraged each day and worried when the unsuspecting every day gardener has no idea about this stuff....this is a great post and will move me to enlarge my compost pile!!

Sheila said...

Linnie, I've often seen plastic bits in compost, too.

Donna, it is scary and discouraging to have to treat earth products as contaminated unless proven otherwise. It is especially disturbing, given that gardeners use so much compost and that it's always being touted to us as "black gold" and the solution to all our soil and growing problems. That's true - but only if we can be confident the compost is organic and chemical-free.

redgardenclogs said...

Wow - how extremely unfortunate. That is just a downright bummer. I'm so sorry you went to all the trouble of collecting it only to find it not worth the risk of using, but I'm glad you did some investigation to find out...and I don't blame you one bit for not wanting to use it. Sticking with your own compost, where you know and control what does/does not go into it is probably the best bet. That's what I'm trying to do, but I'm finding it's really difficult to create as much compost as I want or need - ha! I'm going to have to start hitting up the juice bars, produce managers at grocery stores, and the coffee shops for their scraps if they're willing to let me have them. Good luck, and thanks for this reminder that commercial compost may be questionable!

Sheila Read said...

Aimee, yes it is a definite bummer. Not the tone I tend to take when thinking or writing about gardening, but I thought it was important to share what I found ...

I know, I wish home composting would produce more. We eat mostly veggies, have tons of scraps, throw them in the composter and they just disappear! It's amazing how the compost pile shrinks. But there's just 2 of us, and we don't seem to produce enough food and garden waste make the amount of compost I would like to use.

I'm with you on checking out local restaurants, coffee shops, etc. to see about getting scraps. That is the next step!

Elephant's Eye said...

We used to buy municipal compost full of plastic and glass bits. At least I could pick those out.

Between sewage sludge and cattle feedlots and battery chickens - I now use 'certified organic' fertiliser in small amounts for the roses.

jeansgarden said...

Sheila, This is an important cautionary tale. I'm lucky that there are a number of small companies in Maine producing good quality organic compost. They usually have websites that provide information about what goes into the compost, and I try to stick with compost that has been certified by the Maine Organic Farmers and Gardeners Association. I did have a bad experience with so-called "organic" compost from a local nursery that was full of bits of plastic, some flattened tin cans, and weed seeds. I use a lot of compost because it's how I add organic matter to my very sandy soil, and I don't have a truck so I have to have it delivered. This year, I bypassed the local nursery and paid a hefty delivery fee to get certified high-quality compost from a nursery that's 20 miles away.
BTW, I like the Chebeague Island bumper sticker on your truck! -Jean

Garden Sense said...

Good caution! I use municipal compost and am usually happy with it. This year I've noticed a lot of weed seeds, but it sounds as though I made out pretty well.

Susan in the Pink hat said...

I get bulk compost from a local composting companies cropping up that take produce toss-outs from grocery stores and compost it with sawdust. Not sure where the sawdust is from, but it's better than biosolids. It is expensive, but very, very good.

Sheila Read said...

Jean, that's great to hear that Maine has organic growers who are certifying compost. That is much needed! And I would definitely pay the extra money, too. Although getting it delivered to the island would be another story :)

Elephant's Eye, it seems like a lot of people have had experiences with finding non-earth products in compost. Glass is a new one to me! And, yes, apparently some municipalities in the U.S. (recently San Francisco) had controversies when people found out that they were putting sewage sludge in compost.

Garden Sense, I'm glad you've had good experiences with bulk compost, though the weed seeds are a bummer. I have enough of those already!

Susan, that sounds like a good recipe for compost. Although after my recent experience, I would want to check where the sawdust is coming from (e.g., make sure it's not from pressure-treated wood or plywood). I HATE not being able to trust these products without investigation ...

greggo said...

thanks for the post. I've been using minicipal compost for three years. This past year I added approximately 3 cubic yard to a new garden area. 75
% of the dicot plants (tomatoes, beans, peppers, euportorium, etc.)showed signs of mottling and deformed leaves. I sold pesticides for 20 years and know this is definitely some herbicide issues. This year I began planting dicots again, about 7 weeks ago. I am seeing new damage on tomatoes and some perennials. My butterfly garden, primarily milkweed seedlings are beginning to perish. Its kind of a catch 22, as the composters do not test their manure or compost. I like your plan on going to my own compost with no manure.

The Sage Butterfly said...

Wow...that is scary! We mostly use our own compost, but sometimes we like to apply it to the lawn. We don't have enough for that purpose, so we buy some. I guess we will think twice the next time. Thanks for sharing...

Sheila said...

Greggo, that is terrible about what happened to your vegetables. That's truly frightening. I am so glad now I didn't go ahead and use the compost. Actually, it makes me kind of sick - and angry - that people are thoughtlessly poisoning the soil and that it's being sold to unsuspecting gardeners who are trying to be good stewards of the earth and raise some of their own food. Have you blogged about your experience? You should.

Sage Butterfly, yeah, it's worth thinking twice about. After reading Greggo's comment, I'm glad that I haven't had worse problems with commercial compost ...

greggo said...

comment 2. After reviewing my compost usage practices over the last year, I have determined that there is a way to "manage" the damage. Number one using it on monocots(grasses) is ok,in my meadow garden it does not effect my grasses or does it effect grasses in the yard area. The 'infected' compost I used was taken from the facility in late summer which would have been 'infected' by lawn herbicides(speculation)from clippings. The compost I received in late winter, early spring is comprised mainly of leaf mold which has not caused any issues. So I believe you will have a better chance of safety using the compost comprised of mainly of leaves.

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I am looking a way to save money and also take the ecosmart way to get rid of our restaurant's compost. Any recommendations for commercial composters grand rapids?