Compost, vermicompost, bokashi, or EM: which method should you choose for your food scraps?

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Backyard composter, worm composter, bokashi bucket, effective microorganisms: when you want to put your food scraps to good use, there's no shortage of options, and the names can be confusing. But they don't all do the same thing, and they aren't designed for the same households.

This guide will help you sort it all out in just a few minutes: how each method works, who it's right for, what it produces, and how to combine them. For a detailed head-to-head between a composter and a worm composter, see our guide Worm composter or traditional composter.

Four approaches, two families: decomposing with air, or fermenting

Behind these four names, there are really just two main processes.

• Decomposition with air: bacteria, fungi, and tiny creatures digest the material in the presence of oxygen. This is how backyard composting and vermicomposting work, with composting worms doing most of the work in the latter.
• Fermentation: in a sealed bucket, without air, microorganisms acidify the scraps, a bit like making sauerkraut. This is how bokashi works. The result isn't compost yet: it's a "pre-digested" material that then needs to go back into the soil, into a compost pile, or to the worms.

Effective microorganisms, or EM, aren't a fifth method: they're microorganism preparations used to make bokashi activator or, as an extra boost, in a compost pile.

Traditional composting: who is it for?

This is the go-to method as soon as you have a bit of yard. Whether in a pile, a wooden or plastic bin, or a compost tumbler, it takes both food scraps and a good share of yard waste: grass clippings, leaves, and shredded prunings. That's its big strength: no other method can handle as much volume.

On the other hand, it needs outdoor space, contact with the soil (except for tumblers), and time. It's a great fit for houses with a yard, families who cook a lot of fresh produce, and anyone who wants a soil amendment for their vegetable garden. We cover the different types of equipment in our guide Compost pile or compost bin, and the special case of the drum in our guide Compost tumbler.

Vermicomposting: the apartment solution

In a worm composter, composting worms (Eisenia, which are different from the earthworms in your yard) eat food scraps and produce very fine vermicompost as well as a liquid fertilizer. The process doesn't heat up and doesn't smell when properly managed, so you can set it up in a kitchen, a pantry, or on a balcony. In fact, it's the solution we recommend first and foremost to people living in apartments.

To give you a sense of scale, about 500 worms are estimated to digest roughly 3.5 oz (100 g) of scraps a day. A worm bin like our WORMbox worm composter is therefore a good fit for a household's food scraps, but not for grass clippings or branches. Worms also have their preferences: our guide explains how a worm composter works and what they'll eat.

Bokashi: ferment, then finish in the soil or the composter

Bokashi is an airtight bucket where you pack down your food scraps, sprinkling each layer with fermented grain bran, such as our Bokashi EM compost activator. After a few weeks, the scraps have fermented, and along the way you collect a liquid that can be used diluted.

Its advantages: it fits under the sink, needs almost no maintenance, and accepts leftovers that backyard compost and worms don't handle well, such as small amounts of meat, fish, or dairy. Its limitation, which is important to understand: what comes out of the bucket isn't finished compost. You need to bury it in the soil, mix it into compost, or feed it gradually to worms so the transformation can be completed. It's all explained in our bokashi guide.

Effective microorganisms (EM): a supplement, not a method

EM are blends of microorganisms sold in liquid form, such as the EM-1 stock solution. According to the manufacturers, they mainly combine lactic acid bacteria, yeasts, and photosynthetic bacteria; the stated composition also varies from product to product. They're mostly used to make bokashi activator, and some gardeners apply them as a light watering on a compost pile that's just getting started or that smells bad.

Let's be honest: a compost pile with a good balance of green and brown materials, enough air, and enough moisture doesn't need any additive to work. EM can help in certain situations, but they don't replace a composter, a worm composter, or a bokashi. To learn more, Emy, our effective microorganisms mascot, takes you through our guide to effective microorganisms: their uses in the garden, around the house, or with animals, and what's actually known about them.

Did you know?

Bokashi and backyard compost aren't rivals: the first ferments, the second decomposes. By emptying your bokashi bucket into your composter, you get the benefits of both, and the tricky leftovers are already acidified by the time they reach the yard.

The comparison at a glance

The times below are rough estimates: they vary a lot depending on the season and on maintenance.

Backyard composter (bin or pile)

• Time: 4 to 9 months in a bin for ready-to-use compost, 6 to 12 months in a pile.
• Space: a corner of the yard, on bare soil.
• Scraps: kitchen and yard waste, in large volumes.
• Result: compost to spread in the vegetable garden, the orchard, or flower beds.

Compost tumbler

• Time: about 6 weeks for compost that's still fresh, followed by 3 to 5 months of curing in a pile.
• Space: a patio or a courtyard, even a concrete one.
• Scraps: food scraps and small yard waste, no branches.
• Result: fresh compost to let cure before use.

Worm composter

• Time: about 4 months, with a ready-to-use product.
• Space: a foot or two (a few dozen centimeters) of floor space, indoors or under cover.
• Scraps: mainly raw food scraps, in moderate amounts.
• Result: concentrated vermicompost and a liquid fertilizer.

Bokashi

• Time: about 3 weeks of fermentation, followed by a finishing stage in the soil or in compost.
• Space: a bucket in the kitchen.
• Scraps: almost all kitchen leftovers, including small amounts of meat and dairy.
• Result: a pre-compost to bury or compost, and a liquid to dilute.

Effective microorganisms

• No time frame or equipment of their own: they're an ingredient of bokashi and an optional supplement for compost.

Combining them: bokashi + compost, compost + worms

Many households don't have to pick just one method. A few combinations work especially well:

• Bokashi and composter: the bucket stays in the kitchen and takes all the leftovers, then its fermented contents go into the composter, where decomposition is completed.
• Composter and worm composter: the composter handles the yard waste, while the worm bin processes peels right next to the kitchen, even in winter.
• Bokashi and worm composter: for city dwellers, bokashi lets you process the leftovers worms don't like, then feed them the pre-compost in small amounts.

Key takeaways

Yard and large volumes: the composter. Apartment: the worm composter. Tricky leftovers or very little space: bokashi, finished in soil, compost, or with worms. As for EM, they remain a helping hand.

In summary

Compost and vermicompost break down scraps with air, bokashi ferments them in a sealed container, and EM are supplementary microorganisms rather than a method in their own right. If you have a yard, the composter remains the foundation, possibly paired with a bokashi for tricky leftovers. In an apartment, the worm composter is the most complete solution, and bokashi is a great ally as long as you plan where to finish its contents. Choose based on your home, your scraps, and the time you want to spend on it: there's no bad method, only methods that are a better or worse fit for you.

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Other topics in the guide

Vermicomposting30 fact sheets →Bokashi24 fact sheets →EM microorganisms26 fact sheets →