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Composting is supposed to be the catch-all for food waste, but is it really safe to throw moldy, spoiled canned vegetables into the pile? How rotten is too rotten for the compost heap?
Unless you have a reason to suspect botulism, you can compost spoiled canned vegetables. The bacteria responsible for food spoilage is the same bacteria responsible for turning waste into compost, so moldy or rotten food simply has a headstart on the composting process.
If your canned goods are showing signs of botulism, throw the entire container into a bag and tie it off. Otherwise, you should be safe adding canned foods to the compost bin. Read on for more information on how canned foods can impact the compost pile.
How Canned Vegetables Affect the Compost Pile
Just because you can add canned foods to the compost pile doesn’t mean you should throw 20 jars of salsa into a tumbler.
All canned foods are preserved using one or more of the following ingredients:
- Sugar syrups
- Brines or high salt content
- Low pH or vinegars
- Other preservatives
Composting is a chemical reaction, so the chemical makeup of canned foods can affect the bacteria inside a compost pile.
Compost ingredients are food for bacteria, so when you add an ingredient with a high salt or sugar content, or an extremely low pH, it encourages different kinds of bacteria to reproduce and populate the compost pile.
When the bacteria population of a compost pile changes, it can result in a weird odor, which signifies a change in the overall pH value. Add extra brown ingredients, like shredded paper or cardboard, to offset the canned food.
Salty foods, like pickles or salsas, may slightly increase the salt content of finished compost. Salt kills plants, but unless you are adding large volumes of these foods, it shouldn’t make a noticeable difference.
Bacteria are surprisingly capable of breaking down artificial preservatives and potentially harmful chemicals. Preservatives, dyes, and other chemicals will not affect the finished compost.
Home Canned Vegetables vs. Store-Bought Canned Vegetables
The jury is still out on how much aluminum makes it into commercially-canned foods, but there is a possibility that store-bought canned items may contain small amounts of the metal.
Why does this matter?
Many consumers are worried about chemicals in their food, and rightfully so.
However, bacteria are able to break down most chemicals into their basic elements, and even if they can’t, plants won’t absorb dyes or preservatives, so they can’t transfer from the soil to your vegetables.
Metals, like aluminum, do not break down. Furthermore, plants do take in aluminum, so this may be the one component in store-bought canned foods that can negatively affect your compost pile.
Aluminum is a trace nutrient, which means plants don’t need much, and most can survive without it. In fact, aluminum can be quite toxic even in small quantities, so you may want to limit how much store-bought canned food you add to your compost pile.
Acidic foods, like tomato sauces and pickles, are more likely to absorb aluminum than other canned vegetables.
A few cans shouldn’t make a difference, but if canned foods start to make up a large portion of your green ingredients, you may want to spread the finished compost under some large trees or in a portion of the lawn that has large, established plants.
Home-canned vegetables are stored in jars, not cans. Glass does not leach any metals or chemicals into the food, so you do not have to worry about aluminum toxicity with homemade canned goods.
Botulism in the Compost Pile
Botulism is an extremely dangerous toxin produced from a bacteria (source). While the bacteria and toxins are organic, and they would break down in a compost pile, it’s still dangerous to add these to the compost pile.
Because in order to add the infected food to your compost, you would have to open the can or jar and expose yourself to the airborne toxins. The risk of adding the spoiled food to your compost pile is not worth a potentially life-threatening illness.
If the side of an aluminum can or the lid of a canning jar is bulging, throw the entire container away in a sealed plastic bag.
If the food goes bad after you’ve opened a can or jar, you can safely add the contents to a compost pile, regardless of how gross, smelly, or slimy they are.
The bacteria in compost can break down almost any organic compound and turn it into a healthy soil amendment. As long as you don’t create an entire compost pile out of pickles and spaghetti sauce, the finished product should be reasonably healthy for most soils.
Visit Thriving Yard’s complete guide to composting for more information on managing a healthy compost pile.