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I have a problem. When I start shopping for something, I keep looking at the next size up, the next price point, and the next quality level instead of sticking to my original plan. When I started shopping for compost tumblers, I first saw FCMP’s 37 Gallon Tumbler (the most popular backyard tumbler by far) – and within an hour I was looking at commercial tumblers that can produce tens of thousands of compost per month. Why? I don’t actually know.
Which obviously leads to the question – how big of compost tumbler do I actually need? When I didn’t have a tumbler to reference, this was a very difficult question. Equating gallons of space to pounds of food and yard waste, and then onward to pounds of compost was nearly impossible. Unfortunately, no one was very helpful either. Circumstances are so different that most people were leery of giving me even general guidance. Which is why, after purchasing and using a tumbler for awhile, I’ve decided to reach out to other composters, read over a thousand reviews, and do some math (yuck), and give you the most direct answer possible as to what size of compost tumbler you’ll need:
The average household needs 15 gallons of compost tumbler space for the first adult and 10 gallons per person after that. If you plan to compost yard waste as well, you will need to double that number.
However, your own circumstances will dictate whether you actually need a larger composter (you probably don’t need a smaller one). Compost tumblers readily available for home use vary in size between 12 to nearly 200 gallons. Bigger, however, is not always better. Bigger compost tumblers are harder to turn, harder to fill, harder to empty, and take up way more space. So we need to find your Goldilocks of compost-barrel size.
To give you some examples as to what size works for people, we reached out to people on composting forums and read every composting blog under the sun. Here are the highlights of what people had to say:
“We are a family of 4 and have 3 10’x2′ raised garden beds. We live in a hot climate so our cycle rate is fast enough that we can get by with a single 35-gallon tumbler. If you have more garden space or live in a colder climate you’ll need much more space.”– Charles D. speaking about the Envirocycle 35 Gallon Compost Tumbler
“We first bought a 37 gallon tumbler which turned out to be fine for kitchen scraps and household waste but insufficient for our yard waste, lawn clippings, etc. We now use a 100-gallon system which provides us with plenty of space.”-M. Salade. Currently uses LIFETIME Double Bin Rotating Composter
“I compost mainly to reduce my energy footprint and live more of a zero waste lifestyle. I live in an apartment (alone) and compost food scraps, paper, etc. I keep an 18 gallon mini tumbler on my balcony which provides me with more space than I need. If I had my way I would own a mini double tumbler that had 2 5-7 gallon chambers.”Redditor
“We have a large yard and currently use both a compost tumbler and a compost pile. We bought the cheapest tumbler we could find (27.7 gallons) and use it to give a jump on composting things that would take a long time to break down in our pile. If we were composting all the way to the end in a tumbler it would be insufficient for our family of 5 and we would need 3-4 of the same size.”Jack J. via Facebook
“My wife and I have always been big proponents of hot composting but after a back injury I found I could no longer keep the pile properly turned and aerated. I wanted to find the biggest tumbler on the market and ended up buying one from Jora which holds 106 gallons. I have a large yard and manage to keep it full year round. I could probably fill another one that size with all the lawn clipping, leaves, etc. that I gather but the single composter produces enough compost for all of our flowerbeds and our 1/4 acre garden.”– Maggie and Neal F.
As you can see, recommendations vary wildly. In fact, someone’s recommendation is almost entirely worthless unless you know exactly what their situation is. So here’s ours:
We are a family of 4 that tries to eat as much fresh food as possible (so lots of fruit/veggie scraps). We have a small (<1/4 acre) yard with 2 small raised garden beds, several flower beds, and some small fruit trees. We compost everything we possibly can to produce enough compost for our garden and flower beds. We use a the Schiller Grounds Care Compost Twin which has two barrels of around 95 gallons apiece. We are able to compost all of our grass clippings, food scraps, home paper products etc. We often have to gather dry leaves or other browns from outside our property to make sure out tumbler is balanced.
So, in summary, it’s pretty hard to buy too big of a tumbler, but it’s entirely possible to get one that is too small. If you have a yard, get a medium sized tumbler to start out with – and if needed, you can add another one or a compost pile to increase your capacity.
How much food waste will a compost tumbler hold?
While very few compost tumbler companies will commit to telling you how much compost you can expect or how much their product will hold, we have enough experience that we can give you a general guideline. Unless you have unusual circumstances, you can expect your tumbler to handle 10-15% of its total capacity per week. So a 100 gallon tumbler could accept 10-15 gallons of scraps and waste per week. Now, this doesn’t mean you’ll be producing 10-15 gallons of compost in that time (I wish).
In the US, the average person produces a pound of food waste per day. This will obviously vary drastically in volume depending on the types of food you consume. Finished compost typically experiences at least 75% shrinkage (by volume). A 100 gallon tumbler would typically hold 80 or so gallons of finished compost (leaving some space to tumble), so you would need 320 gallons of compostable material to fill it.
If you are extremely concerned about getting the right size of compost tumbler, you can figure out how many gallons of compostable waste you produce each week and extrapolate tumbler size from that.
Factors that will affect how big of a compost tumbler you’ll need
There are so many different mentalities when it comes to composting. On one end of the spectrum, there are people who live in a small space and simply want a more eco-friendly way to deal with food scraps. On the extreme other end, there are people who live on a homestead and start begging their neighbors for fallen leaves and moldy leftovers so they can fill their multiple compost piles and fertilize a huge garden.
However, no matter what level you are, there are similar factors that will affect how big of a compost tumbler (or pile) you’ll need.
The amount of food waste you produce: One of the negative side effects of cooking from home is that you produce a huge amount of food waste. This is even more true if you eat vegetarian/vegan and can be a significant deciding factor in knowing what size of compost tumbler you need. If you eat out for every meal, you’ll have far less kitchen waste to compost.
How big your yard/lawn is: The bigger your yard is, the more compost it could produce. This is a doubled edged sword because you will also need more yearly compost to amend your soil.
How many family members you have: In general, more people equals more waste. When we had our two daughters, our waste production seemed to triple at least (including our food waste).
Your cycle speed: Your cycle speed is highly dependent on the types of materials you’re composting, the outdoor temperature, and how well you care for your compost. Larger tumblers typically produce compost more quickly because they heat up more efficiently.
Getting the most your of your tumbler space:
If you want to know how big of a compost tumbler to get so as to maximize your compost production, you might be tempted to just run out and buy the largest option available. While that’s not a terrible plan, it’s not quite on point either.
The most advantageous type/size of compost tumbler is the largest dual chamber tumbler that you can reasonably fill. Dual chambers are necessary to finish compost well and avoid excessive screening at the end. You can simply close one chamber up and keep adding fresh scraps to the second one while the first finishes.
The reason that you want as large of a capacity as possible is that compost relies on heat to break down quickly and effectively. If you are composting weeds, difficult kitchen scraps, toxic plants, etc. you’ll want to get your pile as hot as possible – and that means volume. As compostable materials decompose, they produce a large amount of heat. It typically takes a cubic yard of compost in a pile before it has sufficient mass to maintain its own heat. While this is often achievable in a compost tumbler that holds less than a yard, smaller tumblers will produce less heat and be slower.
What is biggest compost tumbler on the market?
Compost tumblers get very very big. There are a lot of massive, industrial-type tumblers to be had – however, you probably don’t need one that could compost your entire house sitting in your back yard. The largest tumbler we can find that isn’t ridiculous for backyard use is Schiller Grounds Care’s 185-gallon tumbler.
If you think that you need a larger tumbler than that..you probably don’t. I would highly recommend using a single compost tumbler, and if you need more space, start a pile. The only reason to own more huge tumblers is if a disability or local law precludes having a compost pile.
For the average family in the average house, start off with the FCMP Outdoor IM4000 which will provide you with 37 gallons of space, and is cheap enough to add additional units as needed.
In the end, knowing how big of a compost tumbler you need isn’t rocket science. Nor is there a solid answer. The best option is to simply make your best guess and get going on it!
If you need us to simplify things a little further, here you go: simply choose whether you want a small, medium, large, or XL compost tumbler and go pick it out on Amazon! Enjoy!
Best Small Tumbler: FCMP Outdoor IM4000
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