Worm Bin Feeding Guide

Red Wigglers thrive on fruit and vegetable scraps, especially soft, non-acidic items. Top choices include: banana peels, apple cores, melon rinds, lettuce, cucumber, squash, pumpkin, coffee grounds (with paper filter), crushed eggshells, tea bags (staple-free), and small amounts of bread or pasta. These foods break down quickly and provide excellent nutrition. Always chop larger pieces to speed decomposition and bury food under 1-2 inches of bedding to prevent fruit flies and odors.

Citrus peels (oranges, lemons, limes, grapefruit) should be fed in very small quantities, if at all. The high acidity and essential oils (d-limonene) can irritate worms' skin and disrupt bin pH. If you do add citrus, chop finely, limit to a tiny amount once every 2-3 weeks, and ensure plenty of crushed eggshells are present to buffer acidity. Many experienced worm farmers avoid citrus entirely to maintain a stable, healthy bin environment.

Meat, fish, dairy products, and greasy foods are strictly off-limits for worm bins. These items: (1) decompose slowly and create foul odors; (2) attract pests like rats, flies, and maggots; (3) can introduce harmful pathogens; (4) may cause anaerobic conditions that produce toxins harmful to worms. Additionally, high-fat foods coat worms' skin and interfere with their ability to breathe through their skin. Stick to plant-based scraps for a healthy, odor-free bin.

The golden rule: feed only when most of the previous food is gone. For a new bin, start with a small amount and wait 5-7 days before adding more. Mature bins can be fed every 2-4 days depending on population size. Overfeeding is the #1 beginner mistake — it leads to odors, pests, and unhealthy conditions. If you see uneaten food accumulating, skip feeding for a week. Worms can survive on bedding alone for extended periods.

Yes, absolutely! Worms don't have teeth — they use a gizzard to grind food, similar to birds. They need fine grit such as crushed eggshells, coffee grounds, fine sand, or rock dust. Crushed eggshells are ideal because they also provide calcium which helps regulate bin pH and supports worm reproduction. Rinse eggshells, dry them, then crush into a fine powder. Sprinkle a small handful over each feeding for best results.

Onions, garlic, leeks, and chives belong to the allium family and should be fed very sparingly. They contain sulfur compounds that produce strong odors as they decompose and can irritate worms in large quantities. A small amount once a month is generally fine, but avoid adding large quantities. If your bin is indoors, you may want to skip them entirely to prevent unpleasant smells. Always bury allium scraps deeply if you do add them.

Coffee grounds are excellent worm food! Worms love them. They provide fine grit for digestion, are rich in nitrogen, and improve bin texture. However, used coffee grounds are nearly pH neutral (the acid goes into your coffee), so they're safe. Fresh unused grounds are acidic and should be avoided or used very sparingly. Also, coffee grounds can heat up in large quantities, so mix them well with bedding and don't add too much at once. Paper coffee filters can go in too!