Yes, you can add worms to your compost bin—and they speed up decomposition

Worms belong in a compost bin. They eat kitchen scraps and yard waste, break it down faster than bacteria alone, and turn it into finished compost in half the time. The worms most gardeners use are red wigglers (also called red composting worms), not the earthworms you find in garden soil. Red wigglers thrive in the warm, moist, food-rich environment of a bin. Earthworms would try to escape because they prefer cooler, undisturbed soil.

You do not need worms to compost—bacteria and fungi will do the job on their own. But worms make the process noticeably faster and give you finished compost in 3 to 6 months instead of 6 to 12. They also reduce odor and prevent the bin from becoming a soggy, anaerobic mess. If you are willing to buy worms upfront and keep the bin conditions right, they are worth the effort.

Key Takeaways

  • Red wigglers are the correct worm species for compost bins; earthworms from your yard will not stay put.
  • Start with 1 pound of worms per cubic foot of bin space, or roughly 1,000 worms for a standard 3-by-3-foot bin.
  • Worms need bedding (shredded paper or cardboard), moisture like a wrung-out sponge, and temperatures between 55 and 77 degrees Fahrenheit.
  • Feed worms gradually—add food scraps in small amounts once a week, and wait until they have mostly eaten the previous batch before adding more.
  • Worms will die if the bin becomes too hot, too dry, too wet, or too acidic from too much food in one spot.

Where to buy red wigglers and how many you need

Red wigglers are sold online by garden suppliers, bait shops, and some garden centers. Search for "red wiggler worms" or "composting worms." Expect to pay $25 to $50 per pound, depending on the seller and shipping distance. One pound contains roughly 1,000 worms.

The number you need depends on your bin size. A standard rule is 1 pound of worms per cubic foot of bin space. A 3-by-3-foot bin that is 2 feet tall holds 18 cubic feet, so you would start with 18 pounds of worms. That sounds like a lot, but worms reproduce in a compost bin—a population will double every 3 to 6 months if conditions are right. Start with 1 to 2 pounds if your bin is smaller, or if you want to see how the worms do before investing more money.

Setting up the bin before the worms arrive

Prepare the bin at least one week before the worms arrive. Add 4 to 6 inches of bedding to the bottom. Bedding is shredded newspaper, cardboard, or office paper—not glossy magazines or colored inks. Soak the bedding in water, then squeeze it out so it feels like a wrung-out sponge. Worms breathe through their skin and will drown in standing water or dry out in a desert.

Mix the damp bedding with a handful of finished compost or garden soil. This introduces the microbes that worms need to digest their food. Let the bin sit for a few days so the bedding settles and the temperature stabilizes. If your bin is in direct sun or an unheated garage, move it to a shaded spot or indoors. Worms slow down below 55 degrees and die above 77 degrees Fahrenheit.

Adding the worms and their first week

When the worms arrive, open the bag and let them rest in the dark for 15 to 30 minutes. Spread them gently over the bedding and cover them with a layer of damp shredded paper. Do not add food yet. The worms need time to adjust to their new home and to eat the microbes in the bedding.

For the first week, keep the bin covered and undisturbed. Check the moisture once—it should feel like a wrung-out sponge, not wet or dry. If it is too wet, add dry shredded paper. If it is too dry, mist it lightly with water. After one week, the worms will have settled in and you can begin feeding them small amounts of food scraps.

Feeding worms without killing them

The most common mistake is overfeeding. Worms eat slowly. If you dump a large pile of food scraps into the bin, they cannot eat it all before it rots and becomes acidic. The acid kills the worms. Instead, bury small amounts of food scraps in different spots around the bin once a week. Bury them under 2 to 3 inches of bedding so they do not attract flies.

Good foods for worms include fruit and vegetable scraps, coffee grounds with filters, crushed eggshells, and shredded paper or cardboard. Do not add meat, dairy, oils, pet waste, or diseased plants. Meat and dairy attract rats and create odor. Oils coat the worms' skin and suffocate them. Diseased plants spread pathogens to your finished compost.

Watch how fast the worms eat. If food scraps are mostly gone after one week, you can add a bit more the next week. If scraps are still there after two weeks, wait another week before feeding again. A healthy worm population in a 3-by-3-foot bin eats about 1 pound of food scraps per week, but this varies with temperature and worm density.

Maintaining moisture and air flow

Worms need oxygen. If the bin becomes waterlogged, the worms will drown and the compost will smell like rotten eggs. Check the moisture every two weeks by squeezing a handful of compost. It should feel damp but not wet—like a wrung-out sponge. If water drips out, the bin is too wet. Add dry shredded paper or cardboard to absorb the moisture, and drill or poke more air holes in the bin walls if it has a lid.

If the compost feels dry and crumbly, mist it lightly with water. Do this on a cool day or in the evening so the water does not evaporate when ready. In hot weather, the bin may dry out faster. In cold weather, it may stay wet longer. Move the bin to a shadier spot in summer if it is drying out too quickly.

Harvesting finished compost and keeping worms alive

After 3 to 6 months, the bottom layer of the bin will turn dark brown and crumbly—that is finished compost. The worms will have mostly moved to the upper layers where the fresh food is. Harvest the finished compost by removing it from the bottom of the bin (if your bin has a door) or by carefully digging it out from the sides and bottom, leaving the worms and unfinished material in place.

Spread the harvested compost on a tarp in sunlight for a few hours. Most worms will burrow away from the light and back into the remaining material. Pick out any worms you see and return them to the bin. Use the finished compost in your garden or potted plants. It is dark, crumbly, and smells earthy—not like rotting food.

After harvest, add fresh bedding to the bin and continue feeding the remaining worms. They will reproduce and rebuild the population. You do not need to buy new worms unless the population crashes from neglect or temperature extremes.

Common mistakes that kill worms

Overfeeding is the number one killer. Worms cannot eat a large pile of food before it ferments and becomes toxic. Add small amounts once a week and wait to see them mostly eaten before adding more.

Waterlogging is the second. A bin that stays soggy suffocates worms and creates anaerobic conditions. Drill more air holes, add dry bedding, or reduce how often you water.

Temperature swings are the third. Worms slow down below 55 degrees and die above 77 degrees. Keep the bin indoors, in a basement, or in a shaded garage if your climate is very hot or cold.

Adding the wrong foods is the fourth. Meat, dairy, and oils create odor, attract pests, and can kill worms. Stick to fruit and vegetable scraps, coffee grounds, and paper.

Frequently Asked Questions

Can I use earthworms from my garden instead of red wigglers?

No. Earthworms are adapted to cool, undisturbed soil and will try to escape a warm, crowded compost bin. They also do not reproduce well in bins. Red wigglers are smaller, more tolerant of crowding, and breed readily in the right conditions. Buy the correct species.

How long does it take for worms to turn scraps into finished compost?

With worms, finished compost is usually ready in 3 to 6 months, depending on temperature, bin size, and how much you feed them. Without worms, it takes 6 to 12 months. Colder temperatures slow everything down, so a bin in an unheated garage may take longer than one in a warm basement.

What do I do if my worms are trying to escape?

Escaping worms signal a problem: the bin is too wet, too dry, too acidic, too hot, or too crowded. Check the moisture first—it should feel like a wrung-out sponge. If it is soggy, add dry paper. If it is dry, mist it lightly. If the bin smells sour, you have overfed. Stop adding food for two weeks and let the worms catch up. If the bin is in direct sun, move it to shade.

Can I add worms to a bin that already has compost in it?

Yes, but wait until the compost has cooled. If you just started the bin and it is heating up from decomposition, the temperature may be above 77 degrees and will kill the worms. Wait two to three weeks for the heat to subside, then add the worms. If the bin is already established and cool, you can add worms anytime.

Do I need to feed worms during winter?

Worms eat much less in cold weather because their metabolism slows down. If your bin is outdoors and temperatures drop below 55 degrees, reduce feeding to once every two to three weeks. If the bin is indoors or in a heated space, continue feeding weekly. In spring, gradually increase feeding as temperatures warm up.