What Do Worms Eat? A Road Map for What To Feed Your Worms

Worms eat organic matter. Anything that has been living eventually becomes worm food. That includes dead plant material, fruits, vegetables, and microbes, both dead and alive.

Even you and I would become worm food, given enough time and decomposition by nature’s other decomposers.

But the lack of space in home worm composting bins means we have to figure out what worms will want to eat right now or, at least, reasonably quickly.

The list below will detail foods that will be safe additions to any household worm farm.

We’ll also have a quick discussion at the end of what might be considered the “best” worm food as well as some final thoughts on the choice of worm food.

What Worms Like to Eat

Pumpkins, Squash, Canteloupe and other Curcurbits

Composting worms will absolutely love eating any members of the cucurbitaceae plant family like pumpkins, squash, cantaloupe, honeydew, watermelon, etc.

These fruits break down very quickly, are high in sugar, and lack the sinewy nature of plants like broccoli, so worms are quick to swarm them in your worm bin.

Melons, pumpkins and other members of the curcurbitae family are great additions in a worm bin. Watch out for water content though!

One note of caution.

Pumpkin and other members of this family are around 94% water!

A favorite past-time of vermicomposters in autumn is to watch how quickly worms will devour a huge helping of pumpkin.

But if you don’t add dry bedding to help sop up that moisture, the bottom of your worm bin will soon become a gunky mess.

Urban Worm Chow, Chicken Mash & Corn Meal

image of urban worm chow
Worm chow should be used as a supplement rather than the primary food source in a worm bin

I’ll make this clear.

Buying worm food shouldn’t be necessary if you are vermicomposting. But food waste and paper waste often do not provide enough protein to get fat, chubby worms.

Fat worms are important to bait sellers as well, so in order to add a little meat to their, uh, “bones,” you can supplement with a protein-rich mix of cornmeal, chicken mash, alfalfa, kelp meal, soybean hulls, and more.

We use this stuff when our worms need a little boost and it works wonders.

Too much worm chow, however, can lead to protein poisoning or “sour crop” for your worms.

Spent Coffee Grounds

Spent coffee grounds are a pH neutral worm food

Spent coffee grounds are a fan favorite here in our Urban Worm Bags!

Some folks express concern over high acidity, but this is only true of unused grounds or the coffee itself in liquid form.

The coffee grounds themselves are pH neutral.

But they are also sterile immediately after being drenched with scalding water, so I find it takes a few weeks before the worms really move in on them.

Your local coffee shop will be more than willing to give you their spent grounds for free, often rebagging them and setting them out for customers to take, no questions asked.

A word of caution: Coffee grounds can dry a bin out, so keep an eye on moisture if you’re adding quite a bit of them.

Oh yeah….toss the filters in too!

Banana Peels

Banana peels are an excellent worm food. Keep an eye out for fruit flies though!

I like to lay banana peels flat on the surface of the worm bin (with the skin facing up) and come back a few days later and turn the peel over to find a cluster of worms beneath. This is also fun to do with cantaloupe!

Banana peels are welcome hosts for fruit fly larvae, and these eggs are often laid before the food waste ever goes into the bin.

So for food wastes like banana peels which are generally considered safe to let sit for a few days, I recommend freezing them in order to kill off fruit fly larvae.

Apple Cores

Another common fruit whose waste is perfect for the worm bin!  Yeah, yeah, I know the seeds don’t break down, but those can be sifted out later.

Apple cores break down quickly, so they’ll be gone in no time!

Pre-Composted Manures

These are slightly more advanced because they can be harder to procure than regular food waste, but popular manures come from cattle, rabbits, and horses. Some folks use pig manure, but it is so liquidy and harder to handle that it’s probably not worth your time.

As a general rule, you will want to precompost most manures as introducing them to your bin, especially a closed system like a Rubbermaid bin, will result in overheating and a toxic environment for your worms.

I love horse manure as I find it is the least maintenance-intensive.

I can put the worms in a mixture of aged and semi-fresh horse manure and pretty much leave them alone. And the carbon-to-nitrogen ratio also allows it to be a serve as a bedding as well as a food, so I don’t find the need to add fresh bedding every time I feed.

One word of caution about horse manure though. It is frequently contaminated with persistent herbicides. Persistent herbicides were designed to selectively kill thatch during hay production, but because they do not break down during the composting process, they can remain in the horse manure.

Vegetable Waste

green food waste

Yeah, yeah, this is a pretty huge category, but your worms will take to pretty much any veggie waste you create during meal preparation.  Carrot peelings, potato skins, broccoli and cauliflower stalks, lettuce, kale, even onion peels (in limited quantities) are perfect for the worm bin.

Vegetable waste like this isn’t prone to overheating your bin either, so this is another low-maintenance food.

What is the Best Worm Food?

What is considered “best” is highly dependent upon your reason for vermicomposting in the first place, whether it’s to achieve a zero waste lifestyle at home, to mitigate the removal of animal manures, or to create highly fungal worm castings, etc.

It is far less dependent upon what the worms will visibly swarm upon.

Household Waste: Excellent Worm Food for a Zero Waste Lifestyle

Mother and dighter feeding an Urban Worm Bag

In this case, most any household waste that would otherwise go to the landfill is a great choice. In an urban environment, where conventional composting may not be an option, letting the worms eat a mixture of shredded cardboard and your own household kitchen waste is probably optimal.

It’s less about the quality of the castings, which may still be excellent, and more about recycling food waste, which is the heaviest food waste you produce.

This makes vermicomposting a highly effective way to reduce your carbon footprint and contribute to a Zero Waste lifestyle!

Animal Manures: The Perfect Worm Food for Farm Management

If your objective is to manage the manure your animals are producing, then you might not want to waste vermicomposting capacity on household waste.

As large amounts of animal manures should be pre-composted before being fed to the worms, you could always add household waste to the composting manure and end up feeding the resulting, partly-finished compost to the worms. Horse manure has an ideal carbon:nitrogen ratio, but like all animal manures, it should go through a precomposting period where heat is released, mass is reduced, and the manure becomes stable enough to feed the worms.

yard waste compost
Woodier inputs to your worm bin can promote beneficial fungal growth

Woodier Waste: The Ideal Worm Food for Fungal Worm Compost

This is an interesting one. We often consider to be good worm food to be the food that worms appear to swarm around; pumpkins, melons, and highly-decomposed veggie waste.

These are typically high-sugar foods, and the worms gather around like kids might around a pile of Twinkies. But bacteria also love foods with high-sugar content, so these foods create conditions where bacteria will proliferate.

To create a more fungal compost, unsexy food like wood chips, decomposing bark, and woodier waste that resembles mulch – and may be even be mulch will provide the carbon sources that fungi can feed upon.

Final Thoughts on What to Feed Your Worms

Can You Put X in Your Bin?

One of the most frequently asked questions, especially for new vermicomposters, is “Can I put (insert whatever substance) in my worm bin?”

The answer is pretty much always “yes, depending on the size of your bin and the amount you plan to feed them.”

Toxicity is always a matter of dosage and while introducing something awful like battery acid or, more benignly, peanut butter to your worm bin wouldn’t be helpful, it doesn’t have to spell doom for your worms either, if in small quantities.

Should You Blend or Puree Worm Food?

No, you don’t neeeeeed to do this, but the worms will consume an apple run through a food processor much faster than they will consume an unprepared core.

Understand though that this process will quickly release water into your bin so ensure you add bedding every time you feed blended foods.

Should You Freeze Food Waste?

Consider freezing organic waste to speed the breakdown and ultimate consumption by the worms. Freezing food waste also helps to kill fruit fly larvae.

Understand though, that the processes of rupturing cell walls has the same water-releasing result as blending food waste.

Most fruits and vegetables are 80-90% water and freezing the foods causes this water to expand (as it becomes ice) and rupture the cell walls.

This will speed up the release of water as the food waste thaws.

Should You Add Bedding When You Feed?


Firstly, understand that bedding also gets eaten by worms. It doesn’t break down as fast as food waste though, which is why I consider it a “slow food.”

Secondly, this bedding also absorbs a lot of water. And because food waste has a MUCH high water content than the 70% your worm bin should have in total, you need to be adding bedding if you are adding food waste.

Feeding without adding bedding can lead to an overwet, overheating, and over-acidic bin.

See here for an article on some great choices for worm bin bedding.

Remember: You can easily have too little bedding. You can almost never have too much bedding.  

I hope this was helpful guidance as you start – or continue – your vermicomposting journey.

If you’re new to vermicomposting, check out The Ultimate Guide to Vermicomposting, a massive blog post that will cover just about any topic related to vermicomposting for the beginner and beyond!

60 thoughts on “What Do Worms Eat? A Road Map for What To Feed Your Worms

      1. Hi Steve.
        My red wigglers seem to be dying/vanishing! I am following all the suggested guidelines but to no avail. The only possible culprit: fruit flies (gnats?) and tiny bugs – I don’t know what it is though. How do one prevent fruit flies? I am really desperate!

        1. In addition to my earlier question: I’ve just read your attachment on preventing fruit flies, and I will freeze everything before adding to the bin from now on. I still don’t know where my worms are disappearing to!

        2. I have purchased red 5thwiggler first time .I have to use their Vermicompost for mango garden ,wheat crop and cotton crop.is it enough to be used for these crops so that it fulfill all minerals needs of these crops .I have to replace urea and DAP fertilizers that are being mostly used in our lands with vermicompost.which nutrients are present in cow dunk Vermicompost???plz guide me in this regard

  1. I just harvested about 2 gallons from my 4-month old UWB! The problem is that it turned out to be fairly alkaline when mixed with coco coir and perlite. Can I feed the worms something to make their castings more acidic? Would citrus help here?

  2. Should the paper (or leather-like) skins of melons, cucumbers, etc. be removed after all of the flesh has been eaten by the worms?

  3. I’m new at this farming , thank you for the tips I bet my fellows will be much happier now.
    What about onion and any spices? Such as garlic 🧄 fresh herds rosemary mint so on thank you once again for your help. You rock.

  4. Where can I find out more about “pre-composting”? I’d like to know more about composting the excess hay and poops from my guinea pigs. I’m really struggling to find consistent information on this and I’d love your perspective. Some people have said I’ll need a separate worm system for this and not to mix it with food scraps because worms will only eat one (the poop) or the other (the food scraps). Now this is the first time I’m hearing of pre-composting. Would appreciate some direction. Thanks!

    1. Hi Ashe,
      Guinea pig and rabbit poop are similar and fortunately, it is pretty safe to put in with worms immediately. Unless you have a LOT of guinea pigs, I am not sure you have enough volume to properly hot compost their droppings anyways as you typically need a volume of 1-2 cubic yards at a minimum to get the hot composting process going.
      Hope this helps!

  5. In addition to my earlier question: I’ve just read your attachment on preventing fruit flies, and I will freeze everything before adding to the bin from now on. I still don’t know where my worms are disappearing to!

      1. Yes, you can use any of these manures. If you want to do this though, the manure should be pre-composted for 4-6 weeks to kill pathogens and stabilize the material to make it more suitable for the worms.

  6. New to worm composting! I have been composting my dog waste with BSF larvae. I have a lot of residue left over that is a bit like wet clay. Do I need to feed the worms anything else if I put some paper in the bin too? I hope this works.

  7. I have a lot of cedar trees on the property, can I use the pine needs and mulch from the branches in the Bin.
    I think this is not good, as I am told it is not good for general composting?
    Too much acid?

    1. Hey Rudy,
      If I had other options, I would probably put them ahead of anything to do with cedar as many varieties of them have anti-microbial properties!

  8. Do egg shells need to be rinsed before putting in UWB? That is, is the little bit of goo left in the shell (or the white membrane from hard-booked eggs) ok for the little gal-guys? Thanks!!

    1. Rinse the eggshells after use. Let a bunch accumulate. Use a small food processor to crush up shells into powder lightly onto food. Provides grit and balanced soil pH.

  9. Thanks for the great suggestions! I will also test to see how well mulched sugar cane will work as a feed. If anyone has already tried it, please let me know about your findings.

  10. I am searching for the best choice of continuous flow earthworm bed equipment. Do you have a favorite choice? What about harvest equipment, shaker table or trommel?

  11. I had compost worms last year in a wood box (~16 square feet) with holes/slats that lives under a tree (plenty of ventilation, plenty of dry bedding material too), but they have disappeared, despite insulating around the bin with dry straw bales. I feel like I am following all the advice you have given here. My friends have had the same thing happen to them – they disappeared over the winter. We live in Vernal, UT and it wasn’t an especially cold winter. I also notice A LOT of sow bugs in my compost. Is it a death sentence to try to put more red wigglers in with the sow bugs? Thanks!

    1. Hi Emily,
      Sow bugs should co-exist just fine with worms. No issue there. As for disappearing worms, this is tough to know. Even a fairly mild winter in Utah is still *winter in Utah* so it wouldn’t surprise me if the cold got them.

  12. Occasionally deer poop in my yard. Can I use deer poop in the worm bin? How do you compost manure?

    1. Absolutely. Deer poop can be composted by itself I believe. Just let it mellow in a pile for a month or two before feeding it to your worms.

  13. Hi, I have a worm farm that was given to me recently and I’m worried it has a pot worm infestation that may be detrimental to the bin’s overall health. Also, the worms are different from my own bin. Are there two species that look similar here? Red wigglers and ??? Can I post a photo or video?

  14. is it better to just feed soil suplments to directly to the soil or what is “best practice” should you sprinkle trace ammounts over each of the green and brown laters for the Red Wiggler, (Glacial Rock Dust. Azomite, Egg, Oyster Shell and Kelp Meal), to inrich the nutruent value of the castings, or would it be better to just aply the mendments straight on your plants?, For instance I followed a youtube article that claim that Oyster Shell added something called caiten (Ive heard that Oyster shell helps strengten cell walls of plants, making them sturdy).

    1. Hi David,

      I don’t think Oyster shells add Chitin to the bin. They would contribute a lot of Calcium which definitely contributes to plant wall formation.
      Oyster shell flour is added to a worm bin for a few reasons. First it is an excellent ‘grit’ to aid worm digestion. Worms do not have teeth, they instead grind their food in a gizzard (like chickens do). Second, the shell adds Calcium Carbonate to the mix for pH control, it keeps the pH balanced and sweet. Third, it does add calcium to the end product in a form accessible to your plants. So, Oyster Shell Flour is good from end to end for vermicomposting.
      The YouTube article may have confused Oyster Shell with lobster or other shellfish waste. Lobsters and Crayfish and Shrimp have an exoskeleton made of chitin. Insects have chitin exoskeletons too. The point is to use the worms to build the enzymes that breakdown chitin. Then add that enzyme containing vermicast to your soil for insect control. Sounds good, right?
      At the moment (late 2021), I’m having trouble finding oyster shell flour. Rumor has it, my supplier had some issue with machinery or regulations for now. But you do want the ‘flour’ powdered material. Folks add crushed oyster shell to their own sadness. The crushed particles don’t dissolve and end up like gravel in the end product. Grinding oyster shell on your own is tough on your grinder/blender. I suggest home cultivators instead use egg shell. Dry the egg shells and run them through your coffee grinder or wet them to run through your blender. Some folks cook the shells to reduce Salmonella (I don’t bother). Egg shell adds calcium same as oyster.
      Is it better to add directly to the soil? Maybe, it is less bother, but if you are raising worms too, then why not benefit both?

    1. Absolutely! Large amounts might be a little tricky because chicken manure is so rich in nitrogen, but you should be fine with small amounts!

  15. I have a couple of bags of almond meal (ground almonds) that are past their use date. Can I add this to my worm bin, and do I need to worry about the nut oil in case it’s rancid? Thank you

    1. I have used out-of-date nut meals without any noticeable detrimental effects for quite some time. I have added them to my bin in two ‘gradual’ ways that avoid overwhelming the worms with this ingredient all at once. (1) mix with other ground ingredients, such as ground outdated/surplus oats, rice, breakfast cereals, protein powder, dried fruits, egg shells etc and use as a ‘worm chow’ sprinkled on the surface of the worm bin. (2) save in a flatish container with a lid and use to ‘crumb’ any wet vegetable matter such as pawpaw or other fruit peels, fruit flesh etc. Hope this helps.

  16. Great article, thank you.
    When adding the wet foods, is it best to add fresh bedding over, under or both over and under the wet food?

    1. I actually like mixing the bedding and food waste together rather than doing the “lasagna” method. You might, hover, consider covering that mix with a thin layer of bedding to protect from fruit flies.

  17. Steve I really appreciate your help on this site. I ‘ve learned so much from you and the other’s comments. I live in Southern California and summers are hot. Something unexpected happened: I had a very large plastic composter that sat on the ground under an orange tree. Over a 2 year period I added coffee grounds, egg shells, kitchen scraps and leaves to it. I covered it with cardboard on top. I was surprised that every couple of months it would decrease to half the amount. I watered it once or twice a month and never turned it. I thought it was a big dry mess in there and I didn’t expect any quality compost. I decided to check out the middle of it after 2 plus years and to my surprise the whole thing was worm castings and thousands of worms. I had no idea. I got about 30 lbs of worm castings from that bin. There was also a very fat lizard that kept the roach population down in there.

  18. Hi Steve. i read in a “Tips” paper that came with my worms that while all veggies may seem appropriate food one should NOT feed carrots or onions. What say ye?

    1. Hi Kim,
      Diatomaceous earth should be used to kill hard-shelled pests without harming the worms. I don’t believe it’s gritty enough to double as a grit.

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