The Community Composting Program at Koiner Farm is creating a truly closed-loop, micro-food system in the East Silver Spring neighborhood.
COMMUNITY COMPOSTING
AT KOINER FARM
The Community Composting Program at Koiner Farm was established in 2020. This program provides on-farm composting capabilities for up to 50 neighboring households. This program is led by CKC's Farm Managers with support from interns an volunteers who work together to learn the ins-and-outs of operating a 3-bin hot compost system on an urban farm.
Last year, the Community Composting Program at Koiner Farm diverted approximately 12,800 pounds of kitchen scraps from the waste stream and produced 18.5 cubic yards of quality compost that was used directly on the fields at Koiner Farm.
Special thanks to the Maryland Sierra Club for providing much of the financial support to construct the 3-Bin Composter at Koiner Farm in 2019 and advance the program in 2022.
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If you have any questions or would like to participate in the Community Composting Program at Koiner Farm by donating your food scraps, please submit this Community Composter Interest Form and send email to hannah@ckcfarming.org.
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All who have taken the compost tour and training are welcome to participate in the Community Composting Program at Koiner Farm. We would love for all of our Community Composters to become sustaining donors at the $10.00 per month - this will help us cover the cost of staff hours, buckets, signage and general upkeep and repairs of the composter. That said, all are welcome to join this program regardless of ability to pay. Those who can pay the full suggested amount (or a little more) help subsidize those who may not be able to pay. Your participation and contribution in this program, no matter how big or small, is greatly appreciated!
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HOW DOES COMMUNITY COMPOSTING WORK?
How does community compost work? As shown in the above graphic, Community Composting is a hyper-local, closed-loop system that provides the double benefits of not only reducing carbon emissions, but sequestering carbon as well. Almost all of our compost inputs - including farm scraps, kitchen scraps, coffee grounds, and saw dust - come from sources within walking distance of Koiner Farm. Local businesses, such as Kefa Cafe and Abernethy's Sticks, save their waste products - coffee grounds and saw dust, respectively - for us to pick up. Neighbors save their kitchen scraps and bring them to Koiner Farm on their own schedule.
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In order to manage all of these compost inputs, we rely on a process called Bokashi.
What is the Bokashi method of composting? Bokashi is an anaerobic fermentation process that is great for composting food scraps. It is very similar to the process of making sauerkraut from cabbage, as it preserves all the nutrients and keeps the scraps from rotting. Bokashi is a centuries-old composting method, believed to have originated in Korea. At Koiner Farm, we use Bokashi as a way to preserve food scraps until we’re ready to add them to the composter. Based on our experiences with urban farm composting, we strongly encourage the adoption of Bokashi as a best practice when composting on an urban farm.
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BOKASHI = fermenting food scrap for composting
Why do I need to do Bokashi when composting on an urban farm? Bokashi is a particularly important piece of the Community Compost Program at Koiner Farm because it uses fermentation to pre-treatment of the food waste, which helps... (1) control when food scraps are added to the composter, (2) increase degree and rate of decomposition, (3) reduce the risk a pathogens, and (4) reduce rodent pressure. ​
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What do I need to do Bokashi? To do Bokashi, you will need a container (like a plastic bucket with a lid) and the Bokashi starter. The Bokashi starter is an organic medium (such as sawdust, spent hops, newspaper, or other) inoculated with the lactic acid bacteria that do the fermenting. The medium is dried, so the bacteria sporulate, which is a kind of suspended animation they can remain in for a long time, waiting for moisture to wake them up.
Having two containers is ideal for Bokashi. At Koiner Farm, we call it bucket-swapping. For most people, something in the range of a 2-5-gallon bucket with an air-tight lid will do. The ideal size is big enough to hold two weeks of food scraps. For a household with two adults, two 2-gallon buckets are perfect. For families of four or more, we recommend two 5-gallon buckets. The buckets are called the “Accumulator Bucket” and the “Fermenter Bucket” - they change roles every two weeks. The exact timing for the fermenting is not critical, since it’s basically preserved food scraps and will last quite a while in this state.
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What’s the Bokashi process? The “Bucket-Swappers” at Koiner Farm keep the “Accumulator Bucket” at their house for two weeks. They fill it with food scraps and a sprinkling of Bokashi starter each day. They are careful to limit air exposure and may use a plastic plate to press out the excess air from the scraps. When the “Accumulator Bucket” is full, they bring it to Koiner Farm, where it sits for the next 2 weeks as a “Fermenter Bucket.” Before they leave, they grab a new “Accumulator Bucket” from the clean-bucket pile, each with a Ziplock baggie of fresh of Bokashi starter inside.
Every two weeks, the interns at Koiner Farm begin the rotation. The rotation includes pulling out the contents of the 3-bin hot composter from right to left and shifting the contents to the next bin. This will leave the left bin of the 3-bin hot composter empty and ready for all farm waste + kitchen waste + coffee grounds + sawdust to be added.
Once the “Fermenter Buckets” are dumped into the first bin of the hot composter, the bucket is rinsed, dried and a Ziplock baggie of fresh Bokashi starter is placed inside.
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What is Bokashi Starter, and how can I make it? You can buy Bokashi Starter, but it’s expensive (in our opinion), so we make our own. For the organic medium (i.e. the base medium upon which the bacteria will live), we use sawdust, but you can also use newspaper, spent hops or other grains. We get the sawdust from a local woodworking company. Sawdust is their waste product, so this partnership furthers our effort to reduce waste stream inputs.
Making Bokashi starter is like following a recipe. To do the whole process from scratch takes about a month. The reason it takes a month is that there are several times when you have to wait several days (or a couple of weeks for step 2), while nature does its thing.
Step 1 - collect and multiply the lactic acid bacteria
The collection is of naturally occurring bacteria spores that are in the air all the time (similar to how you start sourdough).
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Note, lactic acid bacteria are commonly used in food preservation. They are beneficial, and even probiotic - see https://bcdairy.ca/milk/articles/the-probiotic-effects-of-lactic-acid-bacteria.)
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Next, the bacteria are multiplied by fermenting milk. Some of you may have fermented milk to make yogurt or cheese - the product we’re looking for from step 1 is the whey (i.e. the liquid) from the milk fermentation.
Supplies:
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Rice (any kind - doing this step in conjunction with meal preparation is a great idea)
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Milk (half gallon or gallon - even powdered milk works)
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Wide mouth jars or other containers (I use a smaller one for the rice water and a larger one for the milk fermentation)
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Paper towel to put over the container, and rubber band to hold it on (the container needs to “breathe”)
Procedure:
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Wash (rinse) some rice - which you can then cook - and save the rinse water. This has starches from the rice in it, which provide a food source for the natural bacteria that we are going to collect.
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Put the rice water in a wide-mouthed container, cover with a paper towel, and let it sit for a few days. The warmer it is, the less time you’ll need. You know it’s ready when there’s a very slight sweet odor. Now you have a collection of bacteria - some are the lactic acid bacteria that we want, but there are others too.
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Use some of the rice water with bacteria to inoculate milk for fermentation. Any kind of milk will do. We estimate that a half gallon will create enough whey for 12 “Bucket-Swappers” per month (or 1 “Bucket-Swapper” per 6 months). You add the milk to a wide-mouthed container and about 10 percent as much (by volume) of the rice water (i.e. 10:1 ratio of milk to rice water). Cover with a paper towel again, and set in a place out of direct sunlight. In a few days the milk solids will form a curd that floats on top of the whey. At this point, you’re done. Take out the curd and filter the whey through something like an old T-shirt. Store the whey in the fridge for up to 6 months. You can use it for several batches of Bokashi starter. Do whatever you want with the curd - I make soft cheese from it.
Here’s a video about the Step 1 process - it's actually the one we learned from - https://youtu.be/1Ke4OQljVmg
OK, we have whey! We wanted to give you this process in case you want to do it, but because whey is easy to produce in much larger quantities than are needed to make a bath of starter, we can provide you with some whey so you can start right in on Step 2, which is actually making the starter.
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Step 2 - inoculate the Bokashi medium with the lactic acid bacteria
Video - making Bokashi starter from shredded newspaper
Supplies:
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Organic medium (saw dust or shredded newspaper), about a paper grocery bag full (this is what the lactic acid bacteria will bind to)
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2 5-gallon plastic bucket with twist-on air-tight lid (Amazon.com: House Naturals Food Grade 5 Gallon Made in USA Plastic Bucket with Air Tight Screw on Lid)
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½-cup (or so) of molasses (this is the food source for the fermentation that grows the lactic acid bacteria population)
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½-cup (or so) of whey (made during Part I)
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1–quart (or so) water
Procedure (Step 2, Part 1):
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Add the molasses and whey into the water and swirl gently
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Divide the medium between the two buckets
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Pour the water mixture over the medium and mix it thoroughly. You want all the medium to be damp, but not dripping. Use your hands to mix and squeeze the medium until it’s consistently moist.
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Press the medium down with a paper or plastic plate to get all the air out.
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Seal off the top layer with the plate or other divider, to help keep air away from the moist medium.
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Put the lid on the bucket and stick a label with the date on it.
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Let the medium ferment for 2 weeks.
Procedure (Step 2, Part 2... do this after 2 weeks):
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Take the fermented sawdust out of the container and spread it out somewhere to dry. A plywood shelf will work well. It takes 3-4 days, usually, to dry.
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Stuff the dried sawdust into airtight storage containers. I use 1-gallon Ziplock bags which I reuse many times.
Now you’ve got a supply of Bokashi starter that will probably last for 6 months or more - depending on how much you made and your food scrap volume. Each time you add scraps, put a loose layer of starter on top and press down to get the air out.
RULES AND REGS
OF COMPOSTING AT KOINER FARM
The Composting System at Koiner Farm is a coordinate and scheduled system. Please do your best to abide by the Rules and Regs of this program, in order to keep your kitchen scraps moving through the system smoothly.
RULE #1
Remove all stickers from peels.
RULE #2
Cut food scraps into 1-inch pieces and crush up egg shells.
RULE #3
Never put plastic (not even compostable plastic) in our bins.
RULE #4
No printer paper or paper with ink in our bins.
RULE #5
No animal products - including meat, fish, bones, and especially pet waste (eeew!) - in our bins.
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RULE #6
No cooking oils, butters, or salad dressings in our bins.
RULE #7
Never leave your kitchen scraps where animals could get them! All kitchen scraps should be placed into the air-tight 5-gallon buckets located within the metal trashcans.
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RULE #8
Always press out the air and cover your scraps with sawdust when adding scraps.
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RULE #9
If you are a "bin-swapper" (i.e. practicing Bokashi composting at your own house and dropping off your own air-tight 5-gallon bucket of Bokashi-treated kitchen scraps), please place your bucket in the designated area behind the composter.
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RULE #10
If you are not sure what to do, please ask someone at the farm, or send a WhatsApp message to Hannah at (412-979-1172).
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Compost for life...