Pinto Beans & Composting

If you grow your own pinto beans, the plants' lush growth of vines and leaves will provide a great deal of material for your compost pile. Allow the beans to dry on their vines until there's a risk of damage from frost or rain. Once the beans have been harvested, pull the vines and chop them coarsely, then add them to your compost (see References 1). The pods can be added as well, once the beans have been shucked for drying.

Although dried beans seldom spoil unless they become wet, they don't necessarily remain pleasant to eat. As food-science writer Harold McGee points out, old beans take longer to cook than fresh beans and may never soften enough to become edible (see References 2). If you find you have pinto beans that have passed this point, they can be composted (see References 3). Pinto beans are a seed, and even very old ones might surprise you by sprouting. To avoid this, soak the beans overnight and chop them in a food processor before composting them.

Sometimes, fridge-cleaning day brings unhappy surprises. In most cases, you can compost leftover pinto beans that didn't get eaten. As with other kitchen scraps, there is a risk that they'll attract pests (see References 4), so bury any cooked beans at least 6 inches and preferably 10 to 12 inches beneath the surface of the pile (see References 3).

Some municipalities, such as Portland, Oregon, discourage residents from composting beans because of their potential to attract pests (see References 4). To minimize this risk, don't compost beans that have begun to rot or grow mold in your refrigerator; their strong odor is more likely to draw vermin. The Environmental Protection Agency advises against composting food wastes containing meats, animal fats or oils for similar reasons (see References 5). If your beans were cooked with pork, lard, vegetable oil or similar ingredients, they shouldn't be composted.