RODALE NEWS, EMMAUS, PA—If you're learning about organic vegetable gardening, chances are you're also learning a lot about compost, the thing that "happens" as leaves, pulled weeds, and grass clippings, or animal manure, break down into a rich, dark, crumbly, earth-smelling material. High-quality compost is teeming with life, full of beneficial microorganisms that will help improve your soil life and your plants' vitality. It can also help protect against plant disease. And for new gardeners who may not have a simple home-composting system in their yard yet, picking up bagged compost at the municipal or landscaping center, or at a big home-improvement store, may seem simple enough. The problem is, not all compost is created equally, and some manufacturers even use human sewage sludge (which means, yes, human waste, though the industry terms it biosolids). This sludge can be laced with virtually anything that homeowners, hospitals, or industrial plants put down their sinks—endocrine-disrupting pharmaceuticals and shampoo chemicals, industrial solvents, and heavy metals. And who wants to grow vegetables in that?
THE DETAILS: The good news is the use of human sewage sludge is strictly banned in organic agriculture (another reason to eat USDA-certified food). However, many nonorganic farmers do use it to grow food crops, and it's also allowed to be used in municipal composting or store-sold bagged compost, and is sometimes labeled as "organic" or "natural" material. (Use of the term "organic" is strictly enforced in the food industry, but less so in other industries.) The Environmental Protection Agency declares human sludge safe for use as long as it passes testing for nine substances and two indicator bacteria. Which hardly covers all possible contaminants, considering that there are more than 80,000 chemicals in use right now in the U.S. "I have more than nine things under my sink that I wouldn't pour on my food source," says Darree Sicher, founder of the United Sludge Free Alliance. "There's no study on what happens when all of these things are combined."
Beyond the biosolids problem, Organic Gardening magazine tested 30 bags brands of compost and found other major issues, from manure that wasn't finished decomposing and reeked of ammonia to wildly varying application rate instructions to a product that contained bark mulch (something you use in your flower beds, but not your veggie garden) instead of advertised compost. Location also matters because even big-branded companies source compost ingredients locally, and they vary.
Published on: June 16, 2010
Updated on: June 17, 2010