Pros: Sturdy, made from recycled materials, easy to use.
Cons: My first one got stolen. Compost bin envy?
I've owned a Biostack Composter for many years now. The first one was stolen out of my urban back yard just before we moved to Belgium. As my father often says, people will steal anything. I replaced it as soon as we were settled into our new home back in the States. I didn't even consider any other composting system; I was that happy with my Biostack. So I've used the Biostack for about nine of the last thirteen years.
I like the design of the Biostack a lot. The "stack" in the name refers to three individual frames that fit neatly on top of each other. All the parts of the compost bin are made of rigid recycled black plastic. The material makes it rot resistant and suitable for any weather, while the color soaks up solar radiation and encourages the composting process with a little extra heat.
The three separate frames of the composter make turning the compost pretty easy. I just remove the top frame and set it on the ground, where it will become the bottom frame of the Biostack as I rebuild it in place. Then I start removing material from the box, dumping it on the ground inside that frame. The most recently added material gets shifted to the bottom of the new pile, while the mature compost gets exposed. As I work my way towards the bottom of the compost pile, I can remove the middle frame from the original pile, and put it in the new location, where it's still the middle frame. When the oldest material from the original pile has been moved, the lowest frame from the pile moves too, becoming the top frame in the new location. All three frames are identical, so they can occupy any position in the stack.
The Biostack also comes with a bottom plate which I've never used. This is provided, I believe, for areas where rodents can be a real nuisance. It has very narrow slatted openings to allow air and moisture to circulate, while preventing unwanted critters from helping themselves to your compost. The bottom plate won't present any problem to helpful insects that break down material though. Rodents have never been a problem for me. And moving the bottom plate from one location to another would seem to defeat the simplicity of turning the pile. So I've never felt the need to use it.
The lid to the Biostack is solid though slightly cumbersome at times. I have big hands for a woman, and I sometimes have trouble manipulating the lid if I want to completely remove it from the composter. Fortunately, I don't really need to move it just to add compost to the bin. The lid is hinged down the middle, so that I can flip open one half, chuck my kitchen scraps in, and then flip it closed. There is even a flat surface on the underside of the lid which I have sometimes found handy. When the lid opens, the open half swings up and over to lay flat on the closed half. I've carved up overgrown squash on the flat surface of the open half of the lid, retrieving seeds for next year's plantings while also chopping up the flesh so that it breaks down more quickly. The lid doesn't lock onto the top frame, but it does seat itself well enough so that it's quite stable. Also, it's got a sloped shape to it, so that it sheds excess rain off to the sides.
The Biostack has a capacity of about 12 cubic feet. That's a little less than my chest freezer, which is perpetually full. Our two-person household has yet to fill this compost bin, even when adding layers of grass clippings and fall leaves in season. Sure, it may be full just after the grass clippings are added. But within a day or two, they've dried down and there is plenty of room again for kitchen scraps. I guess what I'm getting at is, unless your home generates a LOT of compostable material, or you live in a very cold climate where composting is slowed down for much of the year, the Biostack should be large enough to meet your needs.
The Biostack is not the sort of compost bin which produces neatly delineated batches of mature compost. It's more like a free standing pile, which contains some newly added materials, and some older stuff which has turned into rich garden gold. If you're looking for a bin that really accelerates the composting process, this isn't it. And if you want batches of compost that are uniformly mature, you'd need to have two or more Biostacks and use them sequentially. I take a pretty laissez-faire attitude to composting, and just collect whatever amount of mature humus is at the bottom of the pile each time I turn it.
The Biostack requires some assembly. Each of the three frames or tiers is made up of four interlocking sides. There are no screws or other fasteners, so the pieces just snap together. This is pretty self explanatory and can be accomplished without tools or reference to the owner's manual. The bottom plate likewise snaps together, but the hinged lid comes already assembled.
The Biostack comes with a one year warranty. In the years that I've used my two Biostacks, I never had any problems with its performance. Of course there's normal wear from shovel or pitchfork scratches, and obviously it gets dirty. The material is so tough and the design so simple that I doubt they have many claims under the warranty. If there's nothing obviously wrong with the composter when it comes out of the box, it should provide decades of trouble-free use.
The appearance of the Biostack is pretty unobtrusive. The black color helps tone down its appearance so it doesn't really catch the eye. It's attractive enough as compost bins go, but I wouldn't put it in my living room. Let's just say it's utilitarian.
In summary, I like my Biostack composter a lot and would happily recommend it to others for household use. If you're in the market for a sturdy compost bin, I suggest you consider the Biostack. If yours doesn't get stolen, it'll probably last you a lifetime.
NB: If you happen to live in Alameda County, California, you are probably eligible to purchase the Biostack through the county at a steeply discounted price. My understanding is that other California counties have similar programs. Visit stopwaste.org for more information if you live in the east bay.
Other garden reviews
Seeds: Arugula Sylvetta, Peacevine Cherry Tomato, Cherokee Purple Tomato, Bleu de Solaize Leek, Kale Lacinato, Spicy Bush Basil, Dark Purple Opal Basil, Purple Ruffles Basil
Tools: Ironwood Dibble, Johnny's 520 Broadfork, Biostack Composter, Hori Hori Garden Knife, Forged Bypass Pruners, Anvil Pruners, Vigoro Polyleaf Rake, Ace Select-A-Spray Garden Nozzle, Buffalo Mud Boots,
Reference books: Four-Season Harvest, Backyard Composting, 75 Exciting Vegetables for Your Garden, Root Cellaring, Complete Guide to Making Great Garlic Powder, Great Garden Companions, Living with Chickens, Mycelium Running, Apples,
Seed Vendors: Seeds of Change, Seed Saver's Exchange, Gourmet Garlic Gardens