Sun-Mar 200 Composter, $319
The Sun-Mar is a cinch to assemble: It's just a matter of attaching the drum to two supports and adding wheels if you want your composter to be mobile.
On the first day, I slid open a door in the drum and dropped in some dry leaves, coffee grounds, and chopped-up citrus. (Like the Green Johanna, the Sun-Mar 200 eats browns mixed with greens; also like the Johanna, it will eat almost anything.) I gave it a spin, and suddenly juice and bits of coffee leaked out the sliding door, spraying the lawn below. It was mildly disgusting, but after the mixture dried out I stopped having this problem. (And I knew to jump clear the next time I added juicy scraps.) The Sun-Mar is a clever, two-chamber model that lets you harvest compost as you go. But it has two strikes against it. First, it's a bit labor intensive: You need to spin it twice weekly to aerate the mixture. Second, it's made of all-virgin plastic. (The manufacturer claims this yields a more rugged, longer-lasting product—likely true but still not very green.)
Ease of use: 7
Yuck factor: 7
Total: 22 (out of 35)
NatureMill PRO Edition, $399
The NatureMill PRO, which looks like a CPU tower, is a finicky eater. Bones and peach and avocado pits are strictly forbidden, while acidic foods like citrus, tomatoes, and grapes are allowed only in limited quantities. But—and here's the real advantage of this composter—it's automated. Powered by about 10 watts of electricity per month, the NatureMill mixes your scraps every four hours. Such steady aeration and low heat accelerates the composting process. Just two to three weeks later, when your food scraps are well-chewed, you press a button, and compost sifts into the bottom chamber, which you can slide out and dump into your backyard.
Automation doesn't come cheap—but if you crave efficiency or lack space outdoors, this composter could be for you. It's made largely of recycled materials, and its electricity use is negligible, so it scores well on the green scale. It's also easy to use and has a good filter that soaks up odors.
Ease of use: 8
Yuck factor: 8
Total: 25 (out of 35)
The Green Cone System, $185
Unlike the other composters I've reviewed, the Green Cone produces no harvestable dirt, just water and carbon dioxide. For gardeners, that's a drawback, but for everyone else, that's a plus, because after a bit of upfront work, you don't need to lift a finger.
The first step is digging a hole in an area with decent drainage. Then you insert a slotted basket, attach the cone (which both absorbs heat and circulates air inside), heap dirt back over the sides, and screw on the lid. Finally, you dump your kitchen scraps in the basket and wait for the worms and bugs in your yard to crawl through the basket's holes, decomposing the food.
After this admittedly lengthy setup, you can forget all about your compost. There's no need to aerate the mixture or watch moisture levels. And since the Green Cone eats only kitchen scraps (greens), there's no need to do yardwork for gathering browns. It's basically an organic Dumpster: Just toss scraps in the basket whenever you feel like it. (Making sure, of course, that it doesn't overflow.) The Green Cone can get mildly smelly. But as long as you don't stick your face down the cone, you'll have nothing to worry about.
All in all, the Green Cone is the best bet for anyone who wants to dispose of food scraps in an environmentally conscious way but doesn't want to put any thought into the process from week to week. It's as close to Berlin-style effortless composting as you'll get on this side of the Atlantic.
Ease of use: 9
Yuck factor: 7
Total: 28 (out of 35)
Thanks to Adrienne Kane of Nosheteria, food writer, neighbor, and friend, who shared her hefty supply of kitchen scraps with me.