Composting worms don’t like citrus or spicy foods – here’s why!

If you have a worm bin at home you may already know that red wriggler composting worms have a big appetite. Some would say that the way to a worm’s heart is through their stomach! But just like humans, worms have food preferences and favorites.

As a general rule, scraps that you would normally put down the garbage disposal can be put into your worm bin. Worms are happiest eating an organic, vegetarian diet and require sources of calcium to reproduce and grit to grind up their food. (Adding powdered eggshells every once covers both of these needs!) 

But what about the foods that worms don’t like? The following should only be given to worms in small amounts:

• Citrus Peels & Pieces
• Spicy Foods (Hot Peppers, Onions)
• Plain Bread, Cereal & Pasta
• Leaf Litter

Because worms live in a confined area, it is important to be careful to keep these types of food out of the bin because it can harm them. Worms breathe through their skin and certain foods will irritate or prevent that process. For instance, the natural chemicals and acidity in citrus peels and onions can kill worms and other microorganisms, which can slow down decomposition rates in your bin. A well-maintained worm bin should have a pH measurement between 6.0 and 7.0, so it is best to play it safe and not include too many acidic foods. Foods that are too fatty or oily such as dairy, pasta, or bread can also interfere with the worm’s skin. 

Additionally, materials that are too woody like leaf litter or mulch can be too much for a worm to process. Always keep in mind to chop food into small pieces and bury it to encourage faster processing and to prevent odors and pests. When in doubt stick to the following worm favorites:

• Fruit & peels
• Vegetable scraps & peels
• Coffee grounds, filters, tea bags made of natural materials & strings (remove any staples or plastic labels)
• Eggshells 
• Shredded newspaper, cardboard, or egg car

Composting questions? Give the Solana Center team a call on the Climate Solutions Hotline at (760) 436-7986 ex. 700!