What Do Worms Eat? A Detailed Guide for What To Feed Your Worms

Quick answer : Worms eat soft, rotting plant matter and the microbes growing on it. The best foods are fruit and vegetable scraps, coffee grounds, crushed eggshells, aged manure, and damp cardboard. Avoid meat, dairy, oil, salt, citrus, onion, and garlic. Feed about half the worms' body weight per day at most, and only when the last feeding is nearly gone.

That is the short version. Below is everything I have learned running a worm farm since 2018 what to feed, what to skip, how much, how often, and how it all changes by season and by worm species.

Why Worms Cannot Chew And Why It Matters

Worms have no teeth and no jaw. They cannot bite or tear anything. Their mouth works by suction only.

That single fact explains almost everything about worm feeding.

A worm can only eat material that is already soft enough to be sucked in. Put a whole raw carrot in your bin and it will sit there for a month. Not because worms dislike carrots, but because they physically cannot get at it until microbes soften the outside first.

Here is what is really happening in your bin:

1. You add food scraps
2. Bacteria and fungi colonise the scraps and start breaking them down
3. The material softens
4. Worms eat the softened material and the microbes growing on it

Worms are not really eating your kitchen scraps. They are eating the microbe soup that grows on your rotting kitchen scraps.

Once that clicks, every other feeding decision gets easier. You are not feeding worms. You are feeding microbes, and the worms follow.

The 12 Best Foods for Worms

These break down quickly, feed the microbes well, and keep the bin balanced.

Apples are fine too — cut them up and remove seeds, or you will get apple sprouts in your bin.

Fruits and Vegetables Worms Can Eat

The rule is simple: if it is plant-based and it will rot, it will probably work.

Worm-safe fruits: apples (no seeds), melons, cantaloupe, strawberries, blueberries, mango, papaya, grapes, pears, peaches.

Worm-safe vegetables: carrot tops, zucchini, broccoli stalks, peas, green beans, cucumber, lettuce, spinach, cabbage, squash, pumpkin.

A note on tomatoes and potatoes. Worms will eat both. But tomato seeds survive the trip through a worm's gut, so unless you break the seeds down you will get tomato plants sprouting in your bin. Potato eyes will sprout too. It is not harmful — just messy.

 

Must Read : Do It Yourself Worm Compost Bin: A Simple DIY Guide That Works

 

What NOT to Feed Worms

Some foods do real damage. Here is what I keep out of every bin on my farm, and why.

Meat, fish, and bones. Rot slowly, smell terrible, and attract flies and rodents. There is no upside.

Dairy. Same problem. Cheese and milk go rancid and stink out a bin fast.

Oily and greasy foods. Oil coats bedding and blocks airflow. That creates anaerobic conditions, which is the technical way of saying your bin will start to smell like a swamp.

Salty and spicy foods. Chips, sauces, processed leftovers. Salt harms worms directly and disrupts the microbe balance.

Citrus. Oranges, lemons, limes, grapefruit, and pineapple contain limonene, which is toxic to worms in anything beyond small amounts. Citrus also drives bin pH down.

Onions, garlic, leeks, and hot peppers. Strong-smelling and irritating. Worms avoid them, so they just sit and rot.

Pet waste. Dog and cat faeces can carry pathogens. Never worth the risk.

Fresh manure. See the manure section below aged is fine, fresh is not.

👇 Check out our short video to quick info:

Should I Feed My Worms Manure?

Yes — aged manure from plant-eating animals is one of the best worm foods there is. It is what commercial worm farms have used for decades, including mine.

Why manure works so well:

• Nutrient dense. Manure from cows, horses, rabbits, and llamas is rich in nitrogen, phosphorus, and potassium
• Microbially alive. It arrives already full of the microorganisms worms feed on
• Holds moisture. Helps keep bedding at the right dampness
• Buffers pH. Aged manure tends to neutralise over time and stabilises the bin

Manures to avoid:

• Fresh or untreated manure. Too "hot." High ammonia levels will kill worms. Age it at least a few months first.
• Dog, cat, or any carnivore manure. Pathogen risk.
• Manure from dewormed animals. This is the one that catches people out. If the animal was recently treated with a chemical dewormer, that residue passes through and will kill your worms. Always ask before you take free manure from a farm.

Why Oyster Shell Flour Matters

Oyster shell flour is not food exactly, but it is one of the most useful things you can add to a bin.

What it does:

Provides grit. Worms have no teeth. They grind food in a muscular gizzard using hard particles they have swallowed. No grit means a weak gizzard and slow feeding, even when your food choices are perfect.

Buffers pH. Worm bins naturally drift acidic as food breaks down. Oyster shell flour holds the pH steady in the range worms tolerate.

Supplies calcium. Worms need calcium for body development and for producing cocoons. Low calcium shows up as poor reproduction.

Improves the castings. Calcium-rich castings do more for soil structure when you use them in the garden.

I add a light sprinkle at most feedings rather than a big dose occasionally. Little and often works better.

Crushed eggshells do a similar job on a smaller scale. Rinse them, dry them, and crush them as fine as you can big shards do nothing.

Why Feed Microbial Food?

This follows directly from how worms eat. Since worms are really consuming the microbes on decaying matter, feeding those microbes directly speeds everything up.

What microbial food does:

• Boosts the bacteria and fungi population that worms actually eat
• Speeds decomposition of the scraps already in the bin
• Keeps the bin ecosystem stable and balanced
• Supports worm health, growth, and reproduction

A purpose-made worm chow or microbial blend gives a consistent, balanced feed that kitchen scraps alone cannot. I use it alongside scraps rather than instead of them.

How to Prepare Food the Right Way

Preparation matters as much as what you feed. Four steps make a real difference.

1. Chop everything small. Aim for pieces no bigger than a quarter. More surface area means more room for microbes, which means faster breakdown. A food processor helps but is not required.

2. Freeze and thaw. Freezing ruptures the cell walls in scraps. When it thaws, the material is already partly broken down. This is the single easiest thing you can do to speed up a slow bin, and it kills fruit fly eggs at the same time.

3. Bury it, do not pile it. Pull back the bedding, put the food two to three inches down, and cover it. Buried food stays damp and grows microbes fast. Exposed food dries out, smells, and breeds flies.

4. Balance wet with dry. Every time you add wet scraps, add some dry bedding too; shredded cardboard, newspaper, or dry leaves. This is the mistake I see most often. People feed nothing but wet food scraps and end up with a soggy, sour bin.

How Much and How Often Should You Feed Worms?

The standard figure: one pound of composting worms can process about half a pound of food per day under ideal conditions.

The honest version: that is a best-case number. Real bins run slower. Temperature, moisture, particle size, and how far along the decomposition already is all change the speed.

Never add more than your worms will finish in a week. That is the rule I actually work by.

How often: most bins do well with one or two feedings a week. But do not feed on a schedule. Feed on observation.

The check: pull back the bedding and look at the last feeding.

• Mostly gone → feed again
• Still clearly there → wait
• Slimy, smelly, or covered in mould → stop feeding, add dry bedding, and wait several days

When in doubt, feed less. Underfeeding is easy to correct. Overfeeding creates problems that take weeks to fix.

When to Feed Reading Your Bin

Several signals tell you a bin is ready for more food.

Previous feeding is mostly consumed. The clearest signal. If you can still identify what you put in last time, wait.

The bin smells earthy, not sour. A healthy bin smells like forest floor. Sour or rotten means too much food is sitting.

Worms are active near the surface. Worms gathering where food was is a good sign. Worms climbing the walls is not.

Temperature is in range. Worms eat most actively between roughly 65 and 75 degrees Fahrenheit. Below 50 they slow right down and need much less food. Above 85 they stop eating and try to escape. A cheap bin thermometer is worth having.

Moisture is right. Bedding should feel like a wrung-out sponge. Too dry and microbes stall. Too wet and the bin goes anaerobic.

Rotating Feeding Spots

Do not feed in the same place every time. Divide the bin surface into four or five zones and work around them.

Why it matters:

• Prevents compaction. Waste concentrated in one spot compacts and blocks airflow
• Balances decomposition. The whole bin processes evenly instead of one hot corner
• Prevents odour. Too much food in one place decomposes fast and turns anaerobic
• Encourages movement. Worms travelling to find food aerate the bedding as they go
• Gives you an escape hatch. If one zone goes wrong, the rest of the bin is unaffected

I keep a mental clockwise rotation. Simple and it works.

What Happens If You Overfeed

Overfeeding is the number one mistake in worm composting. I did it my first summer with watermelon rinds and the bin smelled terrible within days.

Signs you have overfed:

• Sour or rotten smell
• Slimy buildup on uneaten food
• White mould spreading across the surface
• Fruit flies
• Worms crawling up the walls or trying to leave
• Excess liquid pooling at the bottom
• Bin heating up

How to fix it:

1. Stop feeding completely
2. Remove the worst of the uneaten food
3. Add plenty of dry shredded cardboard
4. Gently fluff the bedding to get air in
5. Leave it alone for a week

The bin will usually correct itself once the pressure is off. Resist the urge to keep intervening.

Feeding Red Wigglers

Red wigglers are the most common composting worm, and they are the more forgiving of the two species I raise.

How they feed:

• Process food faster than European nightcrawlers
• Handle heavier feeding
• Tolerate wetter, warmer conditions
• Stay in the top few inches where food is

Red wigglers' favourite foods, based on what disappears fastest in my bins: banana peels, melon rinds, pumpkin, soft greens, coffee grounds, and aged manure.

Feeding rate: one to two times per week for most home bins. They can handle more than nightcrawlers, but the same rule applies only what they will finish in a week.

A red wiggler specific note: they are surface feeders. Bury food two to three inches down, not deep. Food buried too far down sits in the anaerobic zone and rots instead of being eaten.

Feeding European Nightcrawlers

European nightcrawlers are bigger, slower, and pickier. Feeding advice written for red wigglers does not transfer cleanly.

Key differences:

The main thing to know: European nightcrawlers do better underfed than overfed. When food goes in faster than it can break down, they do not speed up they get stressed, stop feeding, and start crawling the sides.

Always add fresh bedding with every feeding. This matters more for nightcrawlers than for red wigglers. It controls moisture, reduces odour, and keeps the bin airy.

Grit is non-negotiable for this species. Crushed eggshell, oyster shell flour, or calcium carbonate, added lightly and consistently. Skipping grit leads to slow feeding and weak worms even when your food choices are right.

If you are composting specifically with European nightcrawlers I have a full dedicated guide covering their feeding routine in more depth: What to Feed European Nightcrawlers

👇 Still unsure about the worm food? Checkout our video here :

Season-by-Season Feeding Guide

Worm feeding is not the same all year. Here is how I adjust.

Summer Feeding

Warm weather speeds up microbial activity, so food breaks down faster and worms eat more. But heat also makes mistakes more costly.

What changes in summer:

• Feed smaller amounts more often
• Add more dry bedding to offset wet, watery scraps
• Watch moisture; closely bins swing fast in heat
• Keep bins fully out of direct sun

Best summer foods: watermelon rinds (chopped small, they hold a lot of water), banana peels, pumpkin and squash, leafy greens, coffee grounds, crushed eggshells, and plenty of shredded cardboard to balance the moisture.

Summer fruit fly control. Flies get much worse in heat. Three things fix it: freeze scraps before feeding, bury food deep under bedding, and lay dry cardboard across the surface. Do not overfeed fruit in hot weather.

My summer routine: check moisture, remove uneaten scraps, add dry bedding first, bury the food, rotate the spot, keep the lid ventilated.

Winter Feeding

Cold slows everything — microbes, decomposition, and worms.

• Feed less and less often
• Worms may stop feeding almost entirely below 50°F
• Add extra bedding for insulation
• Move bins into a garage, basement, or shed if you can
• Do not panic if the bin goes quiet; it will pick up in spring

Spring and Autumn

These are the easy seasons and the best time to build worm populations.

• Feeding returns to a normal one to two times per week
• Autumn leaf fall is free bedding; collect dry leaves and store them
• Spring is when reproduction ramps up, so keep grit and calcium topped up

 

Must Read : Red Wigglers vs Earthworms: The Composter's Guide

 

What Worms Need Besides Food

Food alone will not keep worms alive. Five things matter.

Moisture. Bedding at wrung-out-sponge dampness. Too dry and worms cannot breathe through their skin. Too wet and the bin loses oxygen.

Air. Oxygen has to move through the bedding. Compacted, soggy bedding goes anaerobic, which is where the bad smells come from.

Temperature. Roughly 55–77°F is the comfortable range. Above 85°F is dangerous.

Bedding. Shredded cardboard, newspaper, coco coir, or dry leaves. Provides carbon, structure, and moisture regulation.

Grit. Eggshell, oyster shell flour, or a little soil. Required for digestion, not optional.

Darkness. Worms avoid light. Keep the bin covered.

 

What Do Earthworms Eat in the Wild vs in a Bin?

In the wild, earthworms eat decaying leaf litter, dead roots, fungi, bacteria, and organic matter mixed through the soil. Deeper-burrowing species pull leaves down into their burrows to soften before eating.

In a bin, they eat the same thing in concentrated form softened fruit and vegetable scraps, coffee grounds, damp cardboard, and the microbes on all of it.

The diet is essentially the same. A worm bin is just a wild worm's diet, condensed and served faster.

This is also why leaf litter works so well as a bin ingredient. Not fresh green leaves; old, soft, half-decomposed ones. Worms move into that material immediately because it is exactly what they evolved to eat.

My Extra Feeding Tips

After years of running bins, these are the habits that make the biggest difference.

Freeze and thaw scraps. The fastest way to speed up a slow bin, and it kills fruit fly eggs.

Always pair wet with dry. Mushy scraps piled alone create a swamp. Tuck them into dry bedding.

Use old leaf litter. Not fresh leaves. Old, soft, barely-there ones. Worms melt right into them.

Keep grit consistent. A light sprinkle at most feedings beats a big dose occasionally.

Watch the bin, not the calendar. Every bin has its own rhythm. One patch gets cleared in three days, another lingers for two weeks. Learn yours.

When in doubt, wait. Almost no one has ever damaged a bin by feeding too little.

 

Shop What Your Worms Need

• Meme's Premium Worm Chow
• Oyster Shell Flour
• Microbial Compost Food
• Coco Coir Worm Bedding
• Live Red Wigglers
• European Nightcrawlers
• Worm Feeding Calculator

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