Three systems work in a home with no yard: a worm bin, a bokashi bucket, or an electric countertop composter. Pick by what you throw away. If your scraps are mostly peelings, coffee grounds and tea, a worm bin costs the least to run and produces the best finished product. If you need to deal with meat, dairy and cooked leftovers, bokashi is the only one of the three that takes them without complaint. If you want no living organisms in the kitchen and are willing to pay for that, an electric unit dries and grinds scraps in hours, though what comes out is not compost yet.
None of them should smell. When an indoor system does, the cause is nearly always the same: too much food, added too fast, with too little carbon around it. The sections below cover each system in enough detail to set it up on a weekend.
Why bother composting in an apartment?
Food scraps are the single largest category of material sent to US landfills — about 24 percent of everything buried, according to the US EPA — and because they break down there without oxygen, food waste is responsible for roughly 58 percent of the methane released from landfills. A household that diverts its peelings and grounds removes the wettest, heaviest fraction of its trash bag, and the material becomes something useful for houseplants, a balcony planter, or a community garden.
If your building or city offers organics collection, that is the lowest-effort route; our guide to food waste recycling routes covers it. The rest of this article is for people without such a service, or who want the finished product for themselves.
The three indoor systems compared
| Worm bin | Bokashi bucket | Electric composter | |
|---|---|---|---|
| Setup cost | $30–150 (or ~$15 DIY tote) | $40–80 for two buckets and bran | $300–600 |
| Running cost | Nothing beyond bedding | Bran: roughly $10–20 per 2–3 months | Electricity plus replacement carbon filters |
| Accepts meat, dairy, cooked food | No | Yes | Most models yes, in moderation |
| Accepts citrus, onion, garlic | Small amounts only | Yes | Yes |
| Time to usable output | 3–6 months for the first harvest | 2 weeks in bucket + 2–4 weeks in soil | 4–24 hours per cycle, then weeks of curing |
| What comes out | Finished castings, ready to use | Acidic pre-compost that must be buried | Dried, ground scraps; not yet compost |
| Footprint | 24 × 16 in (60 × 40 cm) tote | Two 5-gallon (19 L) buckets | Bread-maker sized, needs an outlet |
| Living organisms to manage | Yes, worms | Microbes on the bran only | None |
| Noise | Silent | Silent | Fan and grinder during cycles |
| Needs somewhere to finish | No | Yes: soil, planter or outdoor heap | Yes: mix into soil or compost |
The last row matters most for apartment dwellers. Only the worm bin produces something usable straight away; the other two need soil to finish, so with no planters, no balcony and no friend with a garden, the worm bin is the only complete system here.
What is the best indoor composting method for an apartment?
For most people it is a worm bin, for three reasons. It costs the least, it produces finished compost rather than a half-processed material, and it has the longest record of research behind it. Both the University of Maryland Extension and Oregon State University Extension publish detailed vermicomposting guides aimed at indoor bins, while an Ask Extension response notes there is very little university research on bokashi by comparison. Bokashi plainly works; the practical guidance for worms is simply better tested.
Choose bokashi instead if a significant share of your scraps is meat, fish, dairy, bread or cooked food, or if keeping a thousand worms under the sink is a dealbreaker for anyone in the household. Choose an electric unit for convenience alone: it is the only option that handles a week of scraps in one overnight cycle with no rules about what goes in.
Setting up a worm bin
Vermicomposting uses red wigglers (Eisenia fetida), a surface-dwelling composting worm, not earthworms from a garden, which burrow deep and die in a shallow bin. According to Oregon State University Extension, a bin should be no more than about 12 inches (30 cm) deep, because red wigglers live in the top few inches of material and anything deeper turns anaerobic beneath them. A standard 18-gallon (68 L) storage tote is the usual starting point.
Sizing. The rule from the extension guides is 1 square foot (0.09 m²) of surface area per pound (0.45 kg) of food scraps added per week. A tote with a 24 × 16 in (60 × 40 cm) footprint gives about 2.7 square feet, enough for a household producing 2–3 lb (1–1.4 kg) of scraps a week.
Worms. Cornell’s worm composting guide suggests half a pound of worms, about 500 individuals, is enough to start a small bin. One pound of red wigglers will work through roughly a pound of food waste per week when the bin is new, according to Cornell; OSU Extension notes that an established, healthy population can process up to half its own weight per day. Start at the lower rate.
Bedding. Fill the bin 6–8 inches (15–20 cm) deep with shredded newspaper, cardboard, or coconut coir, moistened to the wetness of a wrung-out sponge. Bedding is the carbon half of the system and the reason a worm bin does not smell. It should always be visible on top; food goes underneath it.
Temperature. The University of Maryland Extension gives the working range as 55–77°F (13–25°C): a closet, under-sink cabinet or laundry corner, not an uninsulated balcony.
Drainage and air. Drill a row of 1/4-inch (6 mm) holes around the upper sides for airflow and a few in the base for drainage, and stand the bin in a tray. Much liquid in the tray means the bin is too wet.
Feeding schedule for the first 90 days
| Weeks | Feed per pound of worms | What to watch |
|---|---|---|
| 1–2 | Nothing for the first few days, then about 1/2 cup (120 mL), buried | Worms should disperse into bedding, not cluster at the lid |
| 3–6 | Up to 1 lb (450 g) per week, in two or three small feedings | Previous feeding mostly gone before adding more |
| 7–12 | Increase gradually toward 1/2 lb (225 g) per day if it disappears | Any sour smell means back off and add dry bedding |
| 12+ | Steady state; first harvest of castings possible at 3–6 months | Population has roughly doubled |
Bury each feeding under at least 2 inches (5 cm) of bedding, rotating around the bin so the worms follow the food. Avoid meat, dairy, oily food, and more than a small amount of citrus, onion or garlic; otherwise the composting do’s and don’ts list applies.
Setting up a bokashi bucket
Bokashi is fermentation, not composting. Scraps are packed into an airtight bucket in layers with bran inoculated with lactic acid bacteria and yeasts, pressed down to exclude air, and left sealed. The microbes pickle the material rather than rotting it, which is why it can take meat and dairy that would putrefy in an open bin.
The University of Saskatchewan’s gardening extension describes the procedure in useful detail. The bucket needs either a false bottom with a tap, or 2–3 inches (5–8 cm) of dry sawdust in the base to absorb liquid. Add scraps in layers about 1 inch (2.5 cm) deep, chopping bulky items to 2–3 inch (5–8 cm) pieces, and sprinkle 1–2 tablespoons of bokashi bran over each layer. Press the layer down firmly, seal the lid, and repeat with each addition. Open the bucket as briefly as possible.
When the bucket is full, seal it and leave it undisturbed for a minimum of two weeks. This is why bokashi is always run with two buckets: one fermenting while the other fills. A sharp, vinegary smell and a white surface mould are normal. A rotten smell or black or green mould means air got in and the batch has failed.
If the bucket has a tap, drain the liquid every two or three days. Diluted at roughly 1:100 with water it can be used as a plant feed; undiluted it will damage roots.
Finishing. The fermented material is not compost. It is acidic, still looks like food, and needs to be buried in soil to break down. The University of Saskatchewan suggests an indoor method for apartments: put several inches of soil in the bottom of a large tub, tip the bucket contents in, blend thoroughly with the soil, cover with several more inches of soil, and leave for two weeks. Around six weeks after the bucket was sealed, the scraps should have dissolved into the soil entirely. Keep plant roots away from the fermented material for the first two weeks of burial; the acidity will burn them.
How electric composters actually work
An electric kitchen composter is a small heated drum with a grinder and a fan. Over a cycle of a few hours to a day, depending on the model, it heats the scraps to drive off moisture, grinds them to a coarse meal, and vents the exhaust through an activated-carbon filter. The output is dry, crumbly, and roughly a tenth of the original volume.
Two caveats. First, the output is dehydrated ground food, not compost. It has not been decomposed by microbes; it has been dried. Rewet it and it will rehydrate, mould, and smell. It needs to be mixed into soil or an outdoor pile at a low ratio, or left to cure, before it does anything for plants. Second, the carbon filters are consumables, and a saturated filter is the usual reason a unit that started odour-free begins to smell.
There is little independent research on these appliances. The honest description is a food-scrap dehydrator that makes scraps easier to store and carry, and if your route to soil is a community garden or a friend’s heap, that is a real service.
Can you compost indoors without it smelling?
Yes, and a system that smells is telling you something specific. The troubleshooting table covers the common cases.
| Smell | System | Cause | Fix |
|---|---|---|---|
| Sour, rotten | Worm bin | Overfeeding; food rotting before worms reach it | Stop feeding for a week, stir in dry shredded paper |
| Ammonia | Worm bin | Too much nitrogen-rich food, too little bedding | Add a thick layer of dry cardboard, feed less |
| Musty, swampy | Worm bin | Too wet, not enough air | Add dry bedding, check drainage holes, leave lid ajar a day |
| Rotten (not vinegary) | Bokashi | Air got in, or too little bran | Batch has failed; bury it outdoors and start again with more bran |
| Sharp vinegar | Bokashi | Normal fermentation | No action; only opens briefly when adding scraps |
| Burnt or cooked food | Electric | Normal during cycle | Run at night; a saturated filter makes it worse |
| Any smell between cycles | Electric | Filter exhausted or unit not emptied | Replace filter, empty and dry the drum |
A caddy on the counter is a separate problem from the system itself. Emptying it daily, or keeping it in the freezer, removes most kitchen odour whichever system you run.
Do worm bins attract fruit flies?
They can, and it is the most common complaint about indoor vermicomposting. Fruit flies arrive as eggs already on fruit skins, particularly bananas and melons. Three habits keep them out: bury every feeding fully under bedding; keep a sheet of damp newspaper across the whole surface as a lid under the lid; and freeze fruit scraps for 24 hours before feeding, which kills the eggs. If an infestation has started, stop feeding fruit for two weeks and set a dish of cider vinegar with a drop of dish soap beside the bin.
What do you do with the output if you have no garden?
Worm castings are the easy case. They are fine-textured, mild, and can be used straight on houseplants, mixed at up to a quarter of the volume of potting soil, or steeped in water for a day as a liquid feed. A household producing a few pounds of scraps a week harvests a few quarts of castings every few months, which houseplants and a balcony planter absorb without difficulty.
Bokashi and electric output need soil: the soil-tub method above, a deep planter with a spare corner where a bucket’s worth can be buried, or an arrangement with a community garden or a neighbour’s heap. A conventional outdoor heap takes either as an ordinary green addition; our guide to starting a compost heap explains what that pile needs.
Start with half your scraps
The commonest reason an indoor system fails is that it is set up for the household’s total food waste on day one. Every system here needs to ramp up: a worm population has to grow, a bokashi routine needs two buckets in rotation, an electric unit has a filter and cycle rhythm to learn. Run one system on roughly half your scraps for the first month and expand once it has shown it can keep up. A worm bin underfed for a month is fine. One overfed for a week is the one that gets given up on.