Indoor Composting: Bokashi, Worm Bins, Countertop
Three ways to deal with kitchen scraps indoors - bokashi fermentation, a worm bin and an electric countertop appliance - with what the EPA and university extension services say each one produces and how to use it.
No garden and no balcony used to mean no composting. Today there are three ways to handle kitchen scraps indoors: a bokashi bucket, a worm bin, and an electric countertop appliance. They are often sold under the same word, but they produce three different things - and only one of them gives you compost you can use straight away.
We have not run the three side by side, so there are no cost or output figures of ours on this page. What follows is what the US Environmental Protection Agency and university extension services say about each.
What “Indoor Compost” Actually Means
An outdoor compost heap relies on air, microbes and time. Indoors, there is no room for that, so each method is a workaround:
- Bokashi - fermentation in a sealed bucket. The result is a pickled pre-compost that has to finish breaking down in soil.
- A worm bin (vermicomposting) - worms eat the scraps. The result is worm castings, ready to use.
- An electric countertop appliance - grinds and dries the scraps. The result is dried food, not compost.
Choose by what you want at the end: something to feed plants with, or simply less in the kitchen bin.
Method 1: Bokashi
Washington State University Extension defines it as an anaerobic fermentation system for managing food waste using a sealed container and an inoculated bran made of beneficial bacteria and yeast.
How it goes
The same guide sets out the routine:
- Each time you add food waste, sprinkle a handful of bokashi bran on top.
- Press the waste down a little to push out air, and seal the lid tightly.
- Drain the liquid from the tap every few days, to prevent unpleasant odors.
- When the bucket is full, leave it to ferment for about two weeks.
The contents will not look rotted. They develop a pickled smell, which is the sign that fermentation has worked.
What can go in
This is bokashi’s strong point. WSU Extension says it takes almost all types of food waste - fruit and vegetable scraps, cooked food, dairy, meat and even small bones.
What you do with it
The fermented material is not finished compost, and the WSU guide is firm about how to treat it: bury it in soil; do not spread it on the surface or use it as mulch; do not put a large amount in one hole; do not leave it exposed to air; and do not plant straight away. It gives a wait of 2 weeks in warm, active soil and 3-4 weeks in cool or compacted soil.
The liquid drained from the bucket can, the guide says, be diluted and used as a fertilizer. Follow the dilution given by the maker of your bran.
What to weigh
- You need somewhere to bury the contents - a garden bed, a large planter, or a friend’s compost heap.
- The bran is a recurring purchase.
- Two buckets work better than one, so that one can ferment while the other fills.
Suits: households that cook meat and dairy and have some soil within reach. The finished material is a good way to enrich a vegetable bed.
Method 2: A Worm Bin
A bin of bedding and composting worms that eat kitchen scraps and leave castings. The EPA’s home composting guide says that of the 9,000 species of earthworms only seven are suitable, and that one of the most used is the red wriggler, Eisenia fetida; it suggests starting with one pound of worms, about 1,000 of them.
How it goes
From the same EPA guide:
- The bin. Buy one or make it from untreated wood or a plastic storage bin. It should have a tight-fitting lid and be a dark color to keep out light.
- Feed: most fruit and vegetable scraps, coffee grounds and paper filters, crushed eggshells, and paper tea bags without staples.
- Do not feed: citrus fruits, odorous foods like onions and garlic, meat, dairy products, greasy foods, bones or pet waste.
- Temperature. Aim for a bin temperature of 59° to 77°F (15-25°C). The worms can survive at 32° to 95°F if they have at least four inches of bedding - which is why a worm bin belongs indoors, away from a radiator and a sunny window.
- Harvest. After three to six months you can collect the worm castings from the bottom of the bin.
To keep flies away, bury each feeding under the bedding. The EPA’s worm-bin instructions put it plainly: exposed food attracts fruit flies, but covered food scraps don’t.
What you do with it
Castings are the one indoor product that needs no further treatment: the EPA says to use them in pots or in the garden. A handful worked into the top of the potting mix is the usual way to give your indoor plants the benefit.
What to weigh
- The worms are alive, and the bin needs regular attention: food, moisture, bedding.
- No meat, no dairy, little citrus or onion - so a worm bin will not take everything from your kitchen.
- It is slow. Expect months before the first harvest.
Suits: people who want usable compost for houseplants and do not mind looking after the bin.
Method 3: An Electric Countertop Appliance
A plug-in unit that grinds and heats food scraps for some hours and leaves a dry, crumbly material. These are widely marketed as “composters”. The EPA is direct about that: these appliances do not produce compost but rather a dried food scraps mixture that can be added to a composting system, at home or through a collection program.
What you do with it
A University of California researcher who studied this material - dehydrated and ground food waste - writes that, unlike compost, it is not stable; when rehydrated it rapidly degrades, so when added to soil, a waiting period of at least three weeks is best before planting. In the trials he describes, mixing it into soil at 2% by weight benefited corn and wheat, while 5% led to some plant toxicity. A little, mixed in well and left to settle, is the lesson; a thick layer on a houseplant is not.
The simplest use is the one the EPA names: add it to a compost heap or a food-scraps collection.
What to weigh
- It reduces the volume and weight of kitchen waste quickly, with almost no effort.
- The output still has to be composted or rested in soil.
- It uses electricity, and most models have filters to replace. Read the maker’s page for which foods the model accepts, the cycle time, the cost of filters and the warranty.
- It is an appliance and priced like one; compare that with the cost of a bucket or a storage box.
Suits: people whose main aim is less waste and less smell in the kitchen bin, and who have a use for the dried material.
Quick Comparison
| Bokashi | Worm bin | Electric appliance | |
|---|---|---|---|
| What happens | Fermentation in a sealed bucket | Worms eat the scraps | Grinding and drying |
| Meat and dairy | Yes | No | Check the model |
| What comes out | Fermented pre-compost | Worm castings | Dried food scraps |
| Ready for plants? | After 2-4 weeks buried in soil | Yes | After composting, or at least three weeks in soil |
| How long it takes | About two weeks once the bucket is full | Three to six months to first harvest | Hours per batch |
| What you keep buying | Bran | Nothing | Filters and electricity |
| What you need | Soil to bury it in | A spot at 59-77°F | Counter space and a socket |
Which One Should You Choose?
- You have some soil - a bed, big planters, a shared garden - bokashi. It takes every kind of food waste.
- You want compost for your houseplants and like the idea of worms - a worm bin.
- You mainly want less kitchen waste and no upkeep - an electric appliance, with the limits above in mind.
The First Month
Whichever you choose, expect a learning curve: a bucket or bin that fills faster than you thought, one bad smell from overfilling or a lid left loose, and a moment of working out where the output goes. After that it becomes routine.
Frequently Asked Questions
Does indoor composting smell?
A sealed bokashi bucket smells pickled when opened; WSU Extension advises draining the liquid every few days to prevent odors. A worm bin fed sensibly and kept covered smells of earth. A bad smell from either means something is off - too much food, the wrong food, or a poor seal.
Can I use bokashi compost or electric-composter output directly on plants?
No. WSU Extension says not to surface-apply bokashi and not to plant immediately: bury it and wait 2-4 weeks. Dried scraps from an electric appliance are not stable either; the University of California source suggests at least three weeks in soil before planting. Worm castings are ready to use.
How long do worms live in a worm bin?
A colony renews itself, so what matters is the bin, not the single worm. Kept fed, moist and within the EPA’s comfortable range of 59-77°F, a bin keeps working from one year to the next.
What’s the cheapest way to compost in a flat?
A home-made worm bin from a plastic storage box, as the EPA describes, or a pair of bokashi buckets. We have not priced them; compare where you shop, and remember that bokashi needs bran regularly.
Will indoor composting attract flies?
A sealed bokashi bucket should not. In a worm bin, the EPA’s rule is that exposed food attracts fruit flies and covered food does not - so bury each feeding in the bedding.
Recommended Gear on Amazon
- Countertop compost bin - browse current options and reviews on Amazon.
- Bokashi composting kit - browse current options and reviews on Amazon.
- Worm composter bin - browse current options and reviews on Amazon.
As an Amazon Associate, we earn from qualifying purchases - at no extra cost to you. This helps us keep producing free, in-depth guides.