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Kitchen scraps account for 24 percent of Americans’ trash—and almost all of those scraps go into landfills. That’s a shame, because organic waste like banana peels and coffee grounds can be turned into nutrient-rich fertilizer through composting. A few forward-thinking cities (like San Francisco) have programs to pick up your food waste and do the composting for you. The rest of the country has to do it itself. For urban dwellers without the backyard space to create a compost heap, a handful of companies offer small kitchen systems that claim to be easy to use, clean, and odor-free.

CHOW tested the three most popular indoor composting systems with three months’ worth of our test kitchen’s scraps—everything from orange peels to cake batter. Our results are below, with the systems ranked from best to worst.

NatureMill Pro System

The System

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NatureMill Pro

$399

HOW IT WORKS: Waste (along with the sawdust pellets included with the system and baking soda you must add to reduce acidity) is electrically heated in the top of a two-tiered chamber. The machine also mixes, moisturizes, and aerates the food scraps. After the scraps have been thoroughly mixed, the upper chamber automatically opens at the bottom, like a trap door, depositing the waste into the lower chamber, where it breaks down further. After 10 to 14 days, a red light goes on, indicating that the compost is ready to be used. The system also lets you know when there’s a jam and when you need to wait before adding new waste to the upper chamber.

PROS: Odors are minimal (the system produces a natural, subtle scent, like mushrooms or a forest after a storm, and at times a faint dark-chocolate aroma). The NatureMill’s also fast: On average, it can run through about 10 to 15 pounds of food waste per week, producing 1 to 2 pounds of compost. It fits easily in most kitchen cupboards or under the sink, and comes in colors like mint green and red. Because it’s temperature-controlled, it works the same regardless of climate or time of day.

CONS: It’s much pricier than the other systems we tested. Hard items like apple cores and corncobs jammed the system. Long, stringy items like corn husks and kale got tangled in the mixing arms—we had to either cut them up or avoid them. It runs on electricity, though it requires less than even Energy Star–certified appliances.

THE UPSHOT: We plan to keep this, our favorite system, in the test kitchen.

Happy Farmer Kitchen Composter with Bokashi

The System

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Happy Farmer Kitchen Composter with Bokashi

$65.99 for both

HOW IT WORKS: About the size of an office wastebasket, the Happy Farmer kit comes with bokashi, a brown powder that looks like sawdust and is essentially fermented wheat bran. You fill the bin with kitchen scraps and layer them with bokashi, then let the whole thing sit with the lid closed for two weeks. When you open it up you find not soil, but rotted, fermented food that remains physically intact, but that can be added to your garden to increase the soil’s nutrient content.

PROS: The Happy Farmer is small and easy to use. Just open, add food, add bokashi, close, and repeat. You don’t need to cut waste into small scraps first (despite what the website says), the way you do with some other systems.

CONS: The system’s smell, when opened, was described by CHOW’s staff photographer as “rotting corpse.” The end product is unappealing—white, moldy, and resembling moist cotton candy and dryer lint tangled with chunks of decomposing food—which isn’t as easy to approach as dirt. During the two weeks our bin was closed and working, we threw out a lot of food. You’d need a few bins in rotation to be able to compost all of your kitchen scraps.

THE UPSHOT: Too stinky, and not ideal as a kitchen composting system.

Can-O-Worms Worm Composte

The System

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Can-O-Worms Worm Composter with Two Pounds of Red Worms

$169.85 for both

HOW IT WORKS: The system consists of three stackable plastic rings, two feet across and two feet high when stacked, with a base and a lid. We also bought a two-pound box of red worms from the same company that sells the composter, though you could buy your worms from a garden supply store.

To the lowest ring, you add the red worms and a mixture of one cup of soil and cardboard (the latter is included with the system). Food waste goes on top of the middle ring. The top ring is left empty.

Once the bottom ring fills up with vermicompost (worm manure), the worms crawl up to the next ring through small holes. The bottom ring can then be removed and the vermicompost collected to use as fertilizer. The now-empty ring can then be placed on the top of the system and the process repeated.

PROS: In theory, worm compost systems are the most cost efficient—worms eat their body weight in food daily, have a life span of 15 years, and can double in population every few months. Vermicompost is an ideal fertilizer, with a neutral soil pH (measure of soil acidity) of 7, the optimal pH level for food-producing crops.

CONS: You can’t put any animal products in this composter. If you’re as squeamish as we found we were, you will not like having to deal with 2,000-plus live worms. The critters are also, it turns out, rather high maintenance: They’re extremely sensitive to light and heat (we lost some to a week-long heat wave). They are finicky eaters: Ours refused to eat bananas and dandelion greens, for example. The system is big and heavy (it took two people to move it when full), attracted fruit flies, and smelled like a city dump. Additionally, whenever the lid was opened, a few worms would crawl up the sides of the container, fall off, and creep into the depths of the kitchen. Ugh.

THE UPSHOT: The Can-O-Worms system did produce the best compost material, but it is the most malodorous and hard-to-use indoor composting system we tried.

Michele Foley is an associate editor at CHOW.

Published October 08, 2008

Comments

After an intial very bad experience with an earlier model of NatureMill, I was able to get it replaced with a NatureMill Pro. The new model works GREAT and I've been very, very happy with it. We keep ours outside as my husband is picky about odors. You can purchase additonal sawdust pellets from the company, but we found that Feline Pine cat litter looks exactly like the pellets that came with the composter. Make sure it's the non-clumping Feline Pine. It's inexpensive and available at most large pet stores.

Stringy stuff does tend to tangle on the mixing bars, so I cut up long strands such as carrot peels or green onion tops into smaller pieces. I also do not put very fibrous stuff such as artichoke leaves or corn husks in the unit.

Reading this, I'm pleased to live in a forward looking city (Toronto) that picks up my compostable garbage and composts it on my behalf.

I have a worm bin and I really think it's the way to go, but I keep it outside. I can see how it would get the lowest rating for indoor use, though. I keep a plastic container under my sink for scraps and just walk it outside every couple of days to add it to the bin. And you end up really growing an affection for the little crawlies.

Very detailed

About a year ago I wrote a piece on 'Serge the Concierge' about the urban composting offerings of a small Indian company that could.
Here is the link http://www.sergetheconcierge.com/2007...

Take care

Serge

'The French Guy from New Jersey'

It's probably a cultural thing. Bokashi is just about universally used in Korea. The fermentation technology is something familiar to Koreans who know how to make homemade kimchi. But Americans (and not just Americans) tend to think <<yecch! >> about new and different smells. I learned about the bokashi system from a Green Books Guide to composting published in the UK (Nicky Scott: Composting. An easy household guide. Green Books Ltd., Foxhole, Dartington, Totnes, Devon or at www.greenbooks.co.uk).

People who want to try this process can fabricate their own fermenting vessels from plastic containers with lids, and purchase the compost starter from the source you reference in the review.

I was amazed to read that earthworms can live 15 years. Do you have a source for that statistic? From what I see it's about a quarter to a half that. Still impressive, but not as amazing as 15 years. According to the earthworm research group at the University of Central Lancashire:

Researchers have estimated that the potential life-span of earthworms (Lumbricids) under field conditions is 4-8 years. Under laboratory conditions the black headed worm (Aporrectodea longa) has been kept for over 10 years, the brandling/tiger worm (Eisenia fetida) for 4.5 years and the lobworm/nightcrawler (Lumbricus terrestris) for 6 years (Korschelt, 1914).

http://www.uclan.ac.uk/facs/science/e...

We have a worm composter and keep it in our garden. I keep our vegi scraps and coffee grinds in a biodegradable bag in our fridge.

When it is warm I add a layer of wet newspaper to the top of the food pile in the composter to keep the warms moist and cool.

We have had no problems with odor. We keep it in our community garden and we harvest the "TEA" and use it to water. I get about a qt a week. I take the "dirt" and put it on the base of the plants.

I have a question about the vermicompost:
I live in Ohio where winters often offer us weeks or months below freezing. How warm to the worms need to stay? Would they be okay at 40 degrees f for a few months (in a greenhouse-ish area that I keep above freezing with a space heater when things get really cold)?

Does anyone have an answer to jlgarret's question? I also live in a cold climate (Montreal) and would rather keep my worms outside for as much of the year as possible.

Re: vermicomposting
Mick-
From what I've been able to tell, 40 degrees would be a stretch, and even if the worms stayed alive, they wouldn't be much in the mood for eating my scraps (which might be okay...just less composting in the winter). I'm thinking the basement might be a better option, though I'm afraid of the smell.
Anyone have a better informed answer?
Or anyone with experience with the vermicompost in the basement? What's the yuck-factor? I am particularly not fond of flies.

Re: vermicomposting
[Th following answer from Wikipedia still doesn't really clear up the question of a safe lower-end temp for the worms in vermicompost]

http://en.wikipedia.org/wiki/Vermicom...

Climate and temperature

The most common worms used in composting systems, redworms (Eisenia foetida, Eisenia andrei, and Lumbricus rubellus) feed most rapidly at temperatures of 59 to 77 degrees Fahrenheit (15-25 degrees Celsius). They can survive at 50 degrees Farenheit (10 degrees Celsius). Temperatures above 86 degrees Farenheit (30 degrees Celsius) may harm them. [11]. This temperature range means that indoor vermicomposting with redworms is suitable in all but tropical climates. (Other worms like Perionyx excavatus are suitable for warmer climates.[12]) If a worm bin is kept outside, it should be placed in a sheltered position away from direct sunlight and insulated against frost in winter. However, freezing the worms every third year simulates their natural life cycles, and actually promotes a healthy work colony.[13]

It is necessary to monitor the temperatures of large-scale bin systems (which can have high heat-retentive properties), as the feedstocks used can compost, heating up the worm bins as they decay.

These gadgets are for people with too much money. I use large rubbermaid totes with some customization. The worms should be kept at 40-70 degrees. I live in AK and our stupid housesitters let the worms go to about -20. I couldn't believe it but some survived. The housesitters survival is questionable. The eggs survive freezing too.

I definitely would not keep this indoors, it drains and attracts fruit flies. I keep it in the heated garage in the winter (45) and outside in the shade in the summer. My method is not for the squeemish but I don't mind dirty jobs. They produce about 40 gallons of rich compost every year which I use when planting my garden.
The only thing I avoid giving them is citrus.

In defense of Bokashi... I have been using this system for over a year and have had no problems with odor... even when there is meat and shrimp shells in there. You should not have all that mold growth; I suspect your tester was not using enough of the inoculating material or not draining off the tea. One of the great benefits of this system is that you can put oils, meats and stuff in there that other systems can't handle... and not have strong odors.

I never even knew there were indoor composting systems, so thanks for opening this new world to me. I recently started helping my grandmother garden after I saw this article:
http://www.bettyconfidential.com/ar/l...

She has an outdoor compost, but i could use the indoor one since I live in a apt. My mom and I want to start growing some vegetables on our balcony

What do you think?

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