Wednesday, March 24, 2010

gardeners' tool: what's in your fertilizer??

On Saturday my husband came home from the garden store with a little bag of fertilizer labeled "For Organic Gardening!" I was skeptical. Fertilizer is notorious for being full of other contaminants besides the potassium, nitrogen and phosphorous you want out of it.

The bag directed me to the company's regulatory website to read about the ingredients. That website directed me to this one: The Washington State Fertilizer Product Database. Hot dog!!

I looked up the "for organic gardening" fertilizer and discovered that it contained 37.9 ppm arsenic. Arsenic! Just to put that number in perspective, the EPA's arsenic limit for drinking water is 0.010 ppm. That makes the fertilizer levels more than 3,000 times higher than the EPA's limits for drinking water. It was also full of mercury, cadmium, lead, and plenty of other stuff that doesn't belong in my vegetables. And I want to put this stuff on my garden.... really?

Luckily we have a nice big compost pile in our backyard full of rich organic matter for the garden. We returned the bag of fertilizer (and told the store why we were returning it - they were a bit taken aback).

The good news is that you don't need to buy fertilizer additives for your garden - compost is easy to make at home. The bad news is that fertilizer is full of virtually unregulated contaminants. The Washington State database lets you find out what's there - but only after you've bought the stuff. The USDA should crack down on fertilizer makers. The rest of us can learn about organic gardening and make our fertilizer the do-it-yourself way.

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