How to Make a DIY Bokashi Bin for Composting Food Scraps
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Cooked food, dairy, meat, and bones are challenging to compost at home because they stink and attract pests. One way to stop this waste from ending in the trash is to pre-compost it in a bokashi bin. Bokashi composting uses an inoculated starter that ferments the waste, making it unpalatable to most animals. This piece takes you through how to make a simple DIY bokashi bin using recycled buckets and an inoculated starter. Using it will prep kitchen waste for putting on your compost pile or to bury in garden beds.
Though many of us have a compost bin, we are taught that there are things that we simply cannot compost. Cooked food, meat, fish, bones, dairy, and pet waste, to name a few. We can add our approved ‘greens’ and ‘browns’ to the mix, but what can we do with the difficult waste? How do we avoid sending it to the landfill? The answer is to break this material down in a bokashi bin. This revolutionary composting method safely ferments food down to a state that it can then be added to your ordinary compost pile. Though you can buy a bokashi bin starter kit, they’re easy to make if you have a couple of buckets.
Making a DIY bokashi bin is extremely simple, and quick too. The only added expense is the bokashi starter, but if you have the time, you can make it yourself. The piece that follows is an excerpt from Matt Rees-Warren’s new book, The Ecological Gardener. Matt takes you through the benefits of anaerobic composting at home and how to use a couple of old buckets to create a bokashi bin. I’m going to be making two for myself! One for cooked food waste and the other for pet waste.
The Benefits of Anaerobic Composting
While compost is primarily for the benefit of the garden, it would be remiss not to see how it helps reduce the amount of waste from our homes. As mentioned earlier [in the book], in theory, anything of organic origin can be composted. However, some materials will take much longer to decompose or require more effort and maintenance — cutting down branches, etc.
It may seem obvious why sending less waste to landfills is hugely beneficial, but it’s important to understand how conventional waste management correlates to composting. Landfills are a crude form of anaerobic composting. They have no regard for the ingredients and are, therefore, completely ineffective. Landfills produce tons of methane gas that contribute to the climate emergency.
Anaerobic Composting at Home
When we compost at home, we, too, are releasing gases. Aerobic composting produces carbon dioxide and ammonia, although this is only natural as it’s a replication of the ongoing process in the natural world. Anaerobic composting occurs in nature, too. However, unlike landfills that release gases into the atmosphere, these gases are contained by either soil (sediment strata). They can also be ‘locked in’ to the water over many years in bogs or marshes. This is important to understand as it shows that when done incorrectly, composting can easily contribute negatively to the environment.
With this in mind, why would we want to compost anaerobically, anyway? The main reason is that cooked kitchen waste can attract rodents. By sealing these ingredients either underground, underwater, or in a container, we can avoid that outcome. It’s best to think of anaerobic composting at home as a contributor to one’s main composting process. Not as a completely unrelated method. Once you’ve anaerobically composted your ingredients, you can add them to the main compost pile.
Making and Using a DIY Bokashi Bin
Bokashi is a type of dry anaerobic fermentation that includes, among its ingredients, the added input of specifically selected microorganisms, which convert the organic matter into a preserved or pickled substance. This process neutralizes the organic matter and, in a way, pre-digests the food, making it ready for the standard aerobic compost method to take over. It couldn’t be simpler, and the first step is to make the container in which the food waste will be stored.
More Ways to Compost Garden and Food Waste
Here’s some further inspiration on transforming your home, farm, and garden waste into black gold for the garden.
- Easiest Way to Make Compost
- How to Use a Chicken Tractor
- DIY Pallet Compost Bin
- DIY Organic Fertilizers for the Vegetable Garden
How to Make a DIY Bokashi Bin
Equipment
- 6–8 mm drill bit (15/64" in the USA)
Materials
- 2 plastic buckets with lids (15-20 liter / 4-5 gallon)
- inoculated bokashi bran
Instructions
- Source two used 15–20l plastic buckets with sealable lids. You can find them through farm, food or building trades.
- Using a 6–8mm drill bit, drill approximately 15–20 holes in the bottom of one of the buckets. Be careful not to crack the bottom by drilling the holes too closely together (figure 1).
- Place the bucket with the holes inside the bucket without, and begin filling with food waste. Add the organic waste in batches, rather than singular items, in order to create layers (figure 2).
- Then place a layer of inoculated bran over the top and seal the lid shut until you have more waste to add (figure 3). Inoculated bran refers to flaky organic materials – typically wheat bran – mixed with what are known as Effective Microorganisms (EM-1) and some sort of fuel for these microbes, such as molasses. You can make your own inoculated bran by raising your own EM-1 culture, or buy a branded bokashi mixture that already contains it. The former takes time to produce while the latter costs money – the eternal conundrum.
- Once the bucket reaches a quarter full, take the top bucket out and collect the liquid or ‘tea’ from the bottom bucket. A tap can be affixed to the bottom to make this easier (figure 4).
- Once the top bucket is full, set aside for two to three weeks, draining the liquid regularly to allow the waste to ferment. Then take the waste and add it to an existing compost pile. The liquid is an extremely potent, but acidic, inoculated natural fertilizer that can be diluted to a ratio of 50:1 (water:concentrate) and applied directly to the plants or soil.
Thanks! This is a really straight forward article on a topic that can get pretty convoluted sometimes!
FYI, you could use a soldering (cheap) iron instead of drilling to avoid microplastics, just be water off the fumes and take appropriate safety precautions.
Also, 1/4”is a more common measurement in the SAE system than 15/64.” Thanks again!
Hi. You mentioned that you would be using a bokashi bin set up for animal waste. Would this be suitable for dog waste, and would you add the product to your compost bin for making compost for the garden?
I’ve yet to start using it for the cats, but plan on it! I understand that pet waste that’s bokashi composted should be buried in the garden on its own, though. Alternatively, you can dig a hole in the garden to add your pet waste to it as you find it. Each time you add waste, sprinkle a layer of bokashi bran over it. When the hole starts to fill up, cover with at least four inches of soil. It will likely sink down as the waste breaks down, so top it up with soil again in the future if required.