Get the dirt on NatureMill's indoor composter [review]

nature mill photo
CC BY 2.0 Sami Grover

Here's a tip for businesses seeking product reviews—don't send your product to a blogger who has just had a baby. A couple of years ago NatureMill, the makers of this fancy indoor composter we've written about before, did just that. And I confess it's been sitting in the basement ever since.

Part of the problem was the demands of new parenthood. But part of it was that we lived out in the country, fed our food scraps to chickens and, I suppose, I was skeptical about a machine that claimed to do what nature does perfectly well anyway.

Having since moved to the city and gotten the hang of this parenting malarky, I was lamenting the fact that I now had to throw my cooked food, meat, dairy and other rodent- and mould-attracting foods straight in the trash. Then I remembered the box from NatureMill, and dug it out to give it (a very belated) review.

Sami Grover/CC BY 2.0

The first thing I'll say is that it's a pretty good looking, and seemingly solidly constructed product. My model—the Neo—is constructed of TEMPERENE™, a foam-like, insulating material for the housing. Inside is a motor, a heating element, an air-pump and filter, and rotating stainless steel blades which mix composting materials in the upper chamber, before transferring them to a lower chamber with removable tray to finish the composting process.

Sami Grover/CC BY 2.0

As most compost geeks know, composting requires a good mix of nitrogen-rich, wet materials like kitchen scraps, and carbon-rich dry, or brown, materials like woody stems, cardboard, paper or, in this case, sawdust. The NatureMill comes with a small box of sawdust pellets and a box of baking soda—both of which are used to "balance" the addition of kitchen scraps and avoid a slimy, smelly mess. Knowing that sawdust pellets are not always sourced sustainably, I quickly supplemented that supply with a large bag of sawdust/shavings from a woodworker friend of mine, and got to composting.

Sami Grover/CC BY 2.0

The first thing I did was to add food waste. Unlike my outdoor heap, the NatureMill pretty much allows me to add whatever I want: cooked food, breads, and even meat and dairy. The instructions did suggest avoiding brassicas (because of odors) and not adding paper products (to avoid mechanical jams) or citrus (because overly acidic conditions might kill the composting cultures), but I confess I ignored the first two directives. (I did make sure I chopped up paper products with scissors first.) Citrus fruits I just kept adding to our outdoor heap anyway.

I also added a good amount of sawdust shavings and, although this was not suggested in the instructions, I included a trowel-load or two of finished compost from my outdoor heap in the hope that the cultures therein would kickstart the process.

Sami Grover/CC BY 2.0

Kickstart the process it did. I kept adding both cooked and uncooked food during the first week, and balancing the mix with sawdust and baking soda—occasionally adding a little extra of both if it got a little aromatic when I opened the lid. While the instructions say it can take a couple of weeks to get an active culture going, my mix was steaming within days and looked suspiciously like semi-finished compost by the end of the week.

Sami Grover/CC BY 2.0

A week and half into this experiment, I've just transferred my first batch of compost from the upper to the lower chamber where it will sit for a week or so before I can take it out and add it to my cold frame outside, in the hopes that it will give a lift to my rather ragged few arugula and spinach plants I'm growing this winter. The end product is, looking moist, crumbly and just like store-bought or homemade compost.

Sami Grover/CC BY 2.0

It doesn't have any of the worms or larger beasties you'd expect in an outdoor heap—but I'm sure they will come once it's deposited outside. There is, I should note, a slight vinegar odor, but I'm putting this down to it being a first batch, and I'm planning on experimenting with the right mix of sawdust, baking soda and kitchen scraps until I get a more earthy smell.

Pros
Overall, I'm impressed with this sturdy little machine. It's easy to use, it results in a decent end product, and it supposedly uses little more energy than a nightlight. For an apartment dweller or someone who can't manage an outdoor heap, the NatureMill offers an accessible alternative. Even for someone like me who does compost outdoors, it allows me to compost moldy or rotten foods, as well as bread, meat and dairy—items I would not add to my outdoor pile, and some of which would not even be recommended for a worm bin. According to the manufacturers' instructions, the NatureMill even reaches high enough temperatures to safely compost cat litter and dog poop too—although it's not recommended to use the end product on edible plants.

Cons
Composting is a balancing act, and I did notice at various points in the first week that the chamber was getting smelly, slimy or otherwise unpleasant—so I adjusted what I was adding or stopped for a day or two. That was not a big deal, but given this device is supposed to make composting accessible to all, I wonder whether an inexperienced composter might end up with an unpleasant, slimy mess. There was, I noticed, some noise when the mill starts mixing its contents. Because I kept mine in the basement, that noise was not obtrusive—but if it was kept in the kitchen, it might be a little annoying at first. Similarly, while I never smelled odors when the lid was closed, adding new compost did sometimes release a blast of less-then-entirely fresh air from the unit. Again, in the basement that's not a problem. In a tiny New York apartment, maybe more so.

Verdict
Ultimately, this appears to be a great option for indoor composting and/or eliminating waste that you don't want to compost in an outdoor heap. It's not exactly cheap (prices start at $250), but it does produce compost at a ridiculous pace. It's also, I should note, kind of fun. At least if you're a compost geek like me.

Yes, the purists might scoff at the notion of an expensive electric composter, but given the choice between trash trucks hauling away organic matter to bury it and turn it into methane, and a small electric motor helping to turn it into something better, I choose the latter. Even if it just gets a few more people composting, people who don't want to deal with a bin full of worms, then it will have done the world a favor.

So, apologies to NatureMill for taking so long to tell you this. But the NatureMill indoor composter is a pretty kick-ass product.

Order yours here.

Sami Grover/CC BY 2.0

Tags: Composting | Gardening | Living With Less | Waste | Zero Waste

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