Market Farming

[road's end farm <organic101 AT linkny.com>]

On Oct 1, 2007, at 12:26 PM, David Guthrie wrote:

> <x-tad-smaller>i've used the bagged compost and humus from wal-mart and related stores and wondered if there might be heavy metals or other undesirables in the mix...</x-tad-smaller>
>  
> <x-tad-smaller>anyone have an idea?</x-tad-smaller>
>  
I would be suspicious of that as well. I think some sewage sludge materials are still on the market, and they may well have such problems; as might any compost or topsoil if the producers of it aren't careful about possible contamination of their sources. You could try asking the store and/or the company producing the stuff for a complete analysis, including heavy metal levels; I don't know whether you'll be able to get one, or whether the material in the specific bag you've got is likely to be the same as the material they ran the analysis on, as their ingredient sources may vary. If you can't get such an analysis at all, I'd be very suspicious; the store might not have it, but the manufacturer ought to.

Most pesticides don't survive the composting process, but some do; for instance, the herbicide clopyralid can survive composting and has been known to cause problems for crops that the compost was applied to. Your extension agency might be able to tell you what could be a problem, and you could ask for test results for those too; of course, you'd need to know where the stuff originally came from to find out what might be in use there. They could probably also run some basic tests on the stuff for you for not too much money, at least for lead and maybe another couple of the most likely problems. 

There are bagged composts etc. acceptable for organic certification, and those should be OK; but they're often hard to find. Watch out for labels that are using the word "organic" just in the sense of "organic matter"; that doesn't necessarily mean that they're acceptable. The brand I use says "Approved for organic crop production". I also have to check specific brands with my certifier; while those not certified of course don't have to do that, an organic certification agency operating in your area might be a good source of info for approvable brands.

-- Rivka; Finger Lakes NY, Zone 5 mostly
Fresh-market organic produce, small scale