Thursday, January 25, 2007

Killing Our Crops with Compost?

So I’m harmlessly going about the simple task of procuring some compost for a few garden projects, when I stumbled upon some mind-numbing information. The very compost we organic gardeners depend upon for enriching our soils and fertilizing our crops, could very well be undermining our garden’s productivity. No, the act of composting is not to blame, but the prevalence of a certain herbicide, applied to the precious raw materials used to make that compost. If your organic tomatoes didn’t thrive this past season, listen up!

Here’s the deal: growers of grass crops have been using a product called clopyralid, which kills broad-leaved weeds, like dandelions, thistles, etc. So everything from lawn clippings in yard waste, to straw animal bedding, to manure from animals fed hay has potentially been contaminated. This product is particularly slow to break down during composting. But the most troubling fact is that this herbicide will damage (photos of damage):

  • Peas
  • Beans
  • Lettuce
  • Tomatoes
  • Eggplant
  • Potatoes
  • Peppers
  • Sunflowers
While some (in the literature I read) might dismiss the impact on food crops as not being broad-range, those are fairly significant crops, in my opinion. That is nearly the totality of what I grow in my vegetable garden.

It also means you can forget about truly growing organic, unless you have maintained strict vigilance over your own compost production.

Washington State has done much to regulate the use of clopyralid, and the amount found in compost has decreased dramatically since it was first found (about 2001), however, according to Cliff Weed, Pesticide Compliance Program manager at Washington State Department of Agriculture (no I’m not making his name up, truth is more amusing than fiction):

the ban is not nationwide and . . . there are instances where animal feed or bedding brought in from other states or Canada may be contaminated with the herbicide. As a result, Washington will probably not completely eradicate it from compost. (WSDA link)
That also means you might want to check out your state’s stance on clopyralid and whether it has been found in significant concentration in compost in your region.


At January 26, 2007 8:06 AM, Blogger Anthony said...

This is unfortunate news for people who don't make their own compost.

But it's also one more reason for the compost bin to become a familar sight in everyone's backyard.

At January 26, 2007 1:38 PM, Blogger Jade said...

Amen to that, Anthony.

Unfortunately even those who do make their own compost, often don't generate it at a high enough rate to replenish their soils adequately.

At January 27, 2007 3:54 PM, Blogger PeakEngineer said...

The previous owner of this house took terrible care of the yard (in suburban terms), which fortunately means that my use of grass (weed) clippings is probably OK... I still haven't found out what the regulations on clopyralid are in Florida -- if my neighbors use it, it could be contaminating my yard...

At January 31, 2007 3:52 PM, Blogger Jade said...

Good news for you, peakengineer! Seems use of clopyralid on residential turf is not allowed in Florida. However, from a U of Florida Extension (2005) document, it seems Florida does allow use of clopyralid in agriculture.


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