Compost bins or a compost pile are not options for city dwellers with little space, time & means. Here are some fast composting methods to enable you to make your own compost at home with minimal time, effort & cost. Some people class small-scale home composting as cold composting but it can still get very warm and creates good compost fast and effectively.
The best composter seems to be a compost tumbler if you want fast home composting. They’re also called a rotating barrel composter, spinning composter, rotating composter, tumbling composters, composting tumbler bins & rotary composters.
Fast Composting Basics #1: size REALLY matters when making compost. Do you want your home composting to create good compost in 2-6 weeks or 6-24 months? If you want fast, DON'T demand that the tiny composting life forms also break down large pieces of “green” and “brown” composting materials. Our special lists of greens, browns, reds and yellows are designed for the speediest complete composting at home without problems.
Making all composting materials going into your compost tumbler “bite size” for the microbes is how to make compost fast. The closer your composting materials are to crumb size, the faster your DIY composting. It also improves pile insulation and makes more homogeneous compost but reduces air circulation so — tumble often. (all photos enlarge to full screen in new window on click)
Fast Composting Basics #2: Complete pre-mixing of the small “greens” and “browns” prior to adding to your compost tumbler is the second of our fast composting methods. Make that your job and not the work of the rotating barrel composter.
Fast Composting Basics #3: Carefully control the ratio of carbon and nitrogen (C:N) composting materials — your composting recipe. Fast composting techniques mean no mistakes that require you to correct compost already in the composter. Sun-Mar ↓ told us to use a 2:1 brown (C) to green (N) ratio. Cornell University's Waste Management Institute Composting experts ↑ advise a 30:1 brown to green ratio with the resulting completed compost having a 10:1 ratio. We listened to Sun-Mar & are still suffering for it (see below). Maintain large stocks of browns. You'll need them. Greens are abundant. It is very unlikely your kitchen & garden will produce enough browns for your needs.
All green composting materials are still mostly carbon. All brown composting materials have some nitrogen. It is overly simplistic to divide composting materials into greens & browns because everything has it's own, internal C:N ratio.
The “super greens” with the highest amount of nitrogen (soybean meal, fish & meat processing waste, chicken manure, tree trimmings, freshly cut grass) and “super browns” with the highest amounts of carbon (bark, rice husks, sawdust, paper) are an important composting tool . These can help you balance the carbon to nitrogen ration of your compost effectively, efficiently, swiftly, cheaply & easily. Use with caution. And nothing from the “reds”.
Tumbling is a compost aerator. Tumble your compost often to improve aerobic conditions & accelerate decomposition. But that will also dry out the compost so moisturize moderately with a fine spray of clorine-free water as needed. Moisture is more important than correct carbon-nitrogen mix but keep the moisture level in the compost well under 60% or the microorganisms suffocate. Too much tumbling creates balls even with good size & pre-mixing.
Composting is a natural process. Do everything wrong and all composting materials will still decompose eventually. FAST & successful home composting requires good composting techniques and the right equipment.
Wear gloves and wash your hands after handling compost. Home composting does not get hot enough to kill disease pathogens such as E. coli and Salmonella or weed seeds so don't put anything nasty into your mix, such as many of the very best sources of nitrogen.
Compost leachate is NOT “compost tea” nor is it “compost extract”. Follow these guidelines and you'll have little or no leachate which is considered a pollution source needing bioremediation because it can contain pathogens despite being rich in dissolved nutrients. It is unsuitable as a foliar spray. Compost tea is an actively brewed, man-made compost extract. NatureMill warns customers against using leachate from it's composter, saying: "This liquid is NOT compost tea. It may be harmful. ... Compost tea, in contrast, is made by mixing fully stabilized compost with water to create a liquid fertilizer."
Our small piece of land in Bangkok is only 80 square wah (320 m² | 3,444.5 ft²) and most of that is comprised of concrete buildings, a pool and a car port. The remainder is “green area” which we intensely cultivate with grass, flowers, bushes, vines & one tree to offset the land lost to living quarters & offices.
Our rotating barrel composter cannot keep up with our greens. Our home composting system aims to be continually processing about 400 liters (105.7 gallons | 11.35 bushels) of composting materials with the aim of taking no more than six weeks from start to finished garden compost. Otherwise raw materials pil up or we must throw away some of our valuable resources. With about 200 liters of our first compost batch on the verge of completion, we still had twice that amount of greens and browns waiting to be composted.
Most of our plant friends are healthy and grow fast. Now that we are making compost, improved health and faster growth is resulting in more raw composting materials. We are determined to establish a sustainable cycle of home composting that converts all our raw materials into compost in a timely manner while requiring the least amount of time & work by using these advanced composting techniques. Screening compost is not our idea of a good time. Busy people will want to minimize the need for that by minimizing the size of all composting materials before going into the composter.
We define ideal compost as crumbly, fairly dry, dark brown almost black, comprised of small pieces with no smell and nothing recognizable such as grass, leaves or whatever you started with. It should look like coffee grounds. With these fast composting methods, our compost tumbler is making compost in 40 days despite initial misjudgments — and bad advice from the maker of these home composting units about the carbon : nitrogen ratio.
The boldest claim we've heard from any composter manufacturer is that “complete” composting can be achieved in two weeks. Guys who have been doing composting for decades find that laughable. The second boldest claim we have heard was from the maker of our geared rotating barrel composter who said complete composting can be accomplished in six weeks — but in parentheses “(ideal conditions)”.
The “two weeks” timeframe may be unrealistic but we've already proven six weeks is possible with a LOT of effort. That's still too slow for us unless we increase composting capacity. Our Hokkien Tea bushes grow 6-12 inches per MONTH both up and out. We really need high efficiency. Even then, we appear to need greater capacity.
Making composting materials tiny before going into the composter is difficult to do free or cheaply. One compost tumbler manufacture recommends “1-inch pieces”. In our opinion, that is at least 5-10 times too big. We aim for 3-4 millimeters.
We experimented with a commercial-grade, specially motorized, pre-owned compost grinder for awhile which was lent to us by Khun Sompong Goonchanapaijit, the owner of Sompong Karnchang, a large machine shop in Bangkok. He was interested in promoting composting among the 75 million residents of Thailand.
It worked great. Unfortunately, two times certain combinations of composting materials proved too much for the powerful machine and stronger than the steel shaft driving material forward towards the blades in the front. After the steel shaft broke a second time, Khun Sompong concluded the experiment was a failure and said his compost grinder was unsuitable for processing kitchen and garden composting materials.
Our conclusion was the opposite. Of course, it wasn't our expensive compost grinder (about US$1,000 new) that was broken twice. The primary troublemakers were vines and mixing too much dry browns and moist greens into the equipment at the same time.
If you have access to a compost grinder, slow but sure is the key — and omit vines unless previously cut up with garden shears into very short lengths. Green twigs and stems, such as those of our Hokkien Tea shrubs, have almost the same characteristics as vines — long and wiry and with too much tough cellulose to break or cut without using a sharp blade of some type. The compost grinder didn't work well for those garden composting materials.
Otherwise, the compost grinder worked great and the particle size was excellent. It also quickly and effectively dealt with compost gone wrong that had resulted from adding freshly-cut Bermuda grass to the compost tumbler on Day One (1st photo at top of page) without first pre-mixing very large quantities of browns that had been through a compost shredder.
The result appeared to be smooth, black, river rocks in a wide range of sizes up to several inches. We strongly advise energetically and aggressively avoiding their creation. But we found that if you regrind compost while also adding a good quantity of browns it quickly solves this problem. The black goo that emerges can be messy but great stuff to put back into the compost tumbler.
After Khun Sompong took back his compost grinder, the problem of hundreds of black turds in the compost got much harder to solve and required a lot of tiring, hot, tedious, manual labor. The black nuggets had to be put into a strong plastic container with at least an equal volume of fine particles of browns then beat, mashed, stabbed and chopped into until they disintegrated. We found it took fine brown composting materials about three times the volume of the black nuggets to obliterate them and get them on the straight and narrow path toward good compost.
Despite our initial miscalculations regarding the ratio of browns to greens because of misinformation from the maker of the compost tumbler AND our ignorance about the paramount importance of particle size if you are under ANY kind of time constraints — nobody we invited to test our compost could detect any smell whatsoever. That means we got the overall ratio right but not perfect.
What we did NOT underestimate was the need for fast composting methods because at any given moment we can process only half of the raw materials available to us.
After carefully studying more than a 1-2 dozen makes, models and brands of kitchen composter & garden composters, we opted for a compost tumbler with “autoflow” technology. Oops! We have found that most of the time we don't want “autoflow”. We thought it would be the most cost-effective to have compost at all stages of decomposition steadily moving down the line with the oldest and best and most complete emerging at the end. Real life has taught us differently and we have made fundamental structural changes to our garden composter that has neutralized the highly-touted & patented “autoflow” feature. We don't have enough spare time to continually sift & return incomplete compost back to the composter.
We almost got a NatureMill automatic composter which is merely a small, electrified and heated compost tumbler in a nice box. Things that did NOT impress us about the Nature Mill composter were:
- the quality of the compost coming out;
- the tiny amount of compost it produces;
- bad smells overpowering the charcoal filter; resulting in
- the need to pour in large amounts of soda bicarbonate to try and kill the nasty smells; and
- reports of "maggots in NatureMill composter"!
Although we've corrected the fundamental design flaws in our rather expensive compost tumbler to get it to do what we want the way we want, it now seems multiple batches started at regular, appropriate intervals might be the best solution. A compost tumbler is best if you want the swiftest home composting but consider getting a composter with two-compartments, sometimes called “dual composters”. But we suggest that only because we don't see anyone making a three or four-chamber compost tumbler. I guess they want you to buy several but they are expensive.
A two-chamber compost tumbler will only be sufficient for you if the volume of waste emerging from kitchen and garden over a six-week period is only slightly more than HALF the size of one compartment. Because it will take about at least 21-42 days from the day you put in the freshest waste for everything in that compartment to be completely composted. From that point, all organic waste you want to compost needs to go in the other compartment.
We think composting materials in a composter in a wide range of decomposition is much better than trying to store greens until you need them. They won't be “greens in storage”, it'll be a pile of rotting garbage. Decomposition is going to happen whether you want it to or not and regardless of whether you put the waste in a composter or not. The conclusion? You'll need at least two composters or a composter with at least two compartments. And you will probably find that three or more composters or three or more compartments works best — regardless of volume.
The ideal scenario would be batch #1 composting while you are continually adding waste to batch #2 during that process. When batch #1 is complete, stop adding compost to batch #2, close it, and start the countdown.
However, if your waste output in 4-6 weeks exceeds the volume of one compartment then two compost tumblers or a compost tumbler with dual compartments will not be enough.
The next best thing for reducing waste particle size after a compost grinder would be a chipper or compost shredder but they are rare in Thailand all three of those are expensive. Next best thing to use would be a lawnmower. Most homes in Thailand don't even have a lawnmower because they hire gardeners. And many professional gardeners use rotating filament mowers which cut individual blades of grass but not much else, which is the main point of their design — safety. They give way to hard objects and the ground and are just a tiny bit tougher than a blade of grass.
But we already had an electric lawnmower for our lawn of Bermuda grass. However, it is only partially effective in sending cut material into the collection basket behind it. A significant amount goes under the basket or in other directions. We tried going over the waste a few times to reduce size but a lot of stuff ended up stuck in the lawn and the more we ran over the waste and the smaller it got the more it disappeared in the lawn. Hmmm. That clearly wasn't the solution we needed but we already had the mower.
So we grabbed our worst scrap lumber and cut it into inter-locking pieces that could be assembled and disassembled on demand into a small enclosure (the width of the mower and about twice its length) and we put it on a smooth, hard surface. That kept 85% of the waste materials within the enclosure. It also enabled us to carefully select the amount and types of greens and browns prior to being “mowed”.
Processing waste one time resulted in particle sizes under one inch and a good mix of evenly distributed greens and browns. We mowed about half a cubic meter of composting materials (about 17.7 ft³) in about three hours but half an hour was spent figuring out the best way to use the enclosure and process the waste effectively and safely. We will probably mow all the current waste at least one more time before putting it in the composter. If the process doesn't emit too much dust we may try three times. Otherwise we'll sift out the larger pieces and mow only those. After one mow we already have a lot of very fine particles so sifting is probably advisable after the first mow.
If you are interested in vermiculture, you can find details about that at ThaiWorm. If you ave any comments, questions or suggestions, please
Our current experiments are regarding number of tumbles per day. The compost is rotated daily but three rotations seems to be enough and produce fewer balls. We are also testing “Effective Microorganisms” (EM) and their potential benefit on the speed of the composting process. An EM solution was used to moisten our second batch. Two days later we had a noticeably “hot” batch. Fourteen days later, volume had been reduced about 33%. Test subjects reported smell ranged from “smelly, like dirty clothes” to “almost none at all.” We sprinkled a couple handfuls of fine sawdust over the batch and rotated several times.
Batch Two seems to be composting faster. That could be the result of the size-reduction process and pre-mixing of browns and greens prior to adding to the compost tumbler with careful attention to the green-brown ratio as well as the daily rotations. However, if the composting is finished in a significantly shorter time than 40 days then EM may be an important factor.
Our current 400-liter capacity is insufficient to process only our garden waste alone with almost no kitchen waste being composted. For that reason we are reviewing DIY compost tumblers made by other composting enthusiasts with the aim of making our own. Plastic containers don't rust but seem to often have difficulty maintaining their shape when laid horizontal, filled with waste and rotated.
Another problem with DIY compost tumblers is the compost sliding, not tumbling, within the drum because of the internal smoothness. And without a gearing system, rotating can be difficult when full unless handles are added. A lot of careful thought seems to have done into the Mantis ComposT-Twin but with each side holding 10 bushels (352.4 liters | 93 gallons) that is smaller than our current one and holds a total of only 20 bushels (704.8 liters | 186.2 gallons) for both current composting and waste storage. That is probably still not sufficient capacity for our home. ComposT-Twin is nice but expensive at US$500 — and made far from Bangkok.
Both the ComposT-Twin and it's primary competitor Compact ComposTumbler both use galvanized sheet metal to make their drums with caps on both ends to maintain shape. They have only slightly different gearing systems to rotate them. The main difference is the height of the composter from the ground — 32 inches for the ComposT-Twin. But Mike Peck's knock-down design and very compact package size for the ComposTumbler is brilliant.
Main apparent weaknesses of the ComposTumbler design seem to be the lack of internal fins to help mix and break up waste, minimal aeration ports and the low height of the assembled unit. And you have to wonder how poorly his steel is galvanized because of his insistance that the composter must be washed well after each batch is finished.
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