Compost Worm Feeding Guide: How To, the Golden Rules, and Pro Tips
There are 2 golden rules in worm farming: 1) K.I.S.S (Keep it Simple) and 2) everything in moderation. These golden rules apply to feeding your compost worms, watering your worm bins, and just about everything else involved in caring for them. Just remember - you can always add more of something later (but it’s hard to remove things once they've been added to a bin!).
Worms are fantastic eaters and will eat just about anything. But there are foods that can harm them or lead to poor bin conditions, so it's important to stick to a few basics.
In many ways, worms follow a vegan diet. They can eat most things that are from the earth and not from another living creature. When determining what to feed your worms, it's best to follow a few guidelines and use common sense. When in doubt, find something else to feed them!
What to Feed your Compost Worms
The "Go" List of items you should feed compost worms includes most raw/uncooked fruits and vegetables as well as the following items:
- Worms have a sweet tooth so most fruits are a great idea (just not citrus). Compost worms love bananas and banana peels, grapes, melon, pears, berries, peaches, apples, and avocado (but not the pit or rinds)
- Green leafy vegetables (e.g., romaine)
- Pumpkin and squash
- Pulp from juicers (avoid citrus)
- Crushed egg shells
- Coffee and tea grounds in small quantities (too many can lead to an acidic bed which can harm the worms)
- Shredded cardboard, egg cartons, and paper towels
- Most leaves (as long as they haven't been treated with pesticides or herbicides)
Worms actually eat microorganisms that are feeding on the food waste, so they like soft food or food that has been cut into small pieces (this helps accelerate the decomposition process and increases the number of microorganisms for worms to eat).
Pro tip #1: Some folks even use a blender to lightly blend a smoothie for their worms!
The "No Go" list for feeding live worms includes:
- Dairy, cheese, and milk products
- Meat or other animal products
- Cooked foods (due to oil and salt content)
- Citrus fruits
- "Spicy" foods like peppers, onions, garlic, and ginger
- Tomatoes or tomato sauce (it's too acidic for worms)
- Foods cooked with oils
- Foods high in salt content
How Often and How Much to Feed your Worms
Remember in the last section when we talked about everything in moderation with worm farming? This is especially true with feeding your worms. Over-feeding, along with temperature, is one of the easiest ways to quickly kill your worm population. Think of feeding your worms like drinking a bottle of wine - you don't usually drink the entire bottle in 1 glass or gulp. You enjoy it in moderation over several glasses or days. Feed worms slowly and modestly and they will stay happy and healthy.
When I started my first bin I was so excited I overfed the worms and created bin conditions that led to many of them dying or fleeing the bin. Because I fed the compost worms too much, they weren't able to keep up and over time the older food went uneaten and created anaerobic conditions that kills worms. The good news is that there are very simple actions you can take to ensure this doesn't happen!
Here're the golden rules for how often and how much to feed your worms:
- Rule #1: Moderation! You can always add more food later.
- Rule #2: For the first feeding, feed 1/5 to 1/4 of the weight of your worm population. For example, if you bought 1 pound of red wigglers, feed them 1/5 to 1/4 pound of food scraps.
- Rule #3: Never feed your compost worms until all food from the prior feeding is consumed/processed. You'll know the compost worms have fully processed the prior feeding when 1) the food is no longer visible on the surface of the worm bin and 2) the worms are not grouped together in a ball where you fed them.
- Rule #4: Don't bury the food! Compost worms are surface dwellers and will generally not eat food that is more than an inch or 2 below the surface. Uneaten food will lead to anaerobic conditions that will kill your live worms. It is ok to sprinkle a little of their original bedding (which should already be in the bin) over the food, but the food should never be buried and should be visible to your eye.
- Rule #5: See rule #1!
- Rule #6: After the first feeding, feed the worms 1/3 to 1/2 of their weight. So if you purchased 2 pounds of worms, feed them 2/3 to 1 pound of food at a time.
Pro tip #2: You may not always have good worm food on hand so buy a small compost bin or get a small pail and place your worm-worthy fruits and veggies in the pail for later!
It's important to keep in mind worms won't die if they aren't fed for a few days or even a week or 2 in most cases. Remember the bedding you placed in the bin when setting it up? That's a food source for worms and they will eventually consume all of it and turn the bedding into worm castings. They need additional food but they can survive without it for longer than you think.
Thanks for reading! If you have any questions or comments, shoot us an email or check the other tips and how to articles on our blog. And happy farming!