DIY Food Scrap Digester/Composter

comments (19) May 21st, 2010

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yourownvictorygarden Greg Holdsworth, contributor
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Properly composted food scraps can be turned into an excellent fertilizer for gardens. However, composting food scraps in an open pile can attract some unwanted urban pests - rats, mice, raccoons and who-knows-what. One of the simplest ways to compost food scraps is in a sunken garbage can. Also called a "bio digester", the magic of this food waste composter is that it's partially buried in the ground. There, holes allow earthworms, microbes, and other critters to 'walk on in' and do what they're good at. A tight-fitting lid allows protection from unwanted pests, excessive rainfall, and drying winds.


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  Dinner is served!
  Learn more about composting...
The list of things you'll need:

• Galvanized metal trash can w/lid (about $30 new). Plastic should be avoided.
• Electric drill
• Drill bit - at least 1/4"
• Shovel
• Gloves (no blisters on my watch)
• Masking tape
• Permanent marker
• Spot to dig in


Step 1. Drill about 20-30 holes, at least 1/4-inch, in the bottom of the can.

Step 2. Drill 20-40 more holes in the sides of the can, but only in the lower third. This is the part which will be covered by soil.

Step 3. In a well-drained spot, dig a hole about 15 inches deep (about half as deep as your container)

Step 4. Set the can into the hole. Then, push the soil back in around the sides and press it down with your hands, foot or the shovel

Step 5. Your new digester is ready to use! Collect food scraps, storing them in a container in your kitchen, and once or twice a week, throw the food scraps into the food scrap digester. I also add a little soil after the scraps to add more microbes and to increase the surface area to be broken down.

Step 6. Here's a cool tip: Take a piece of masking tape and place it at the top of the compost mixture. Then take a permanent marker and write the date that the digester was full and left to compost. You can open the lid periodically to see that the level has dropped from the material being broken down. Sweet!

If odor or fruit flies are a problem, you can add leaves, grass clippings, sawdust, straw, or shredded paper to place a thin layer on top of each new food scrap addition to the digester. No worms need to be added to this digester. Worms will find their way into the digester through the holes and will help break down the food scraps. If pests are still opening the lid, you can tie a bungee cord to the lid handle and hook it to the handles on the sides of the garbage can.

Harvesting the Compost

Depending on your household’s food habits, a digester will fill in 2-6 months. Harvest the compost by shoveling the upper foot or so of undecomposed food off to one side and shoveling the dark, soil-like compost out of the bottom of the digester. If the unfinished compost is wet and smelly, mix it with some soil and wait a week for it to dry up. Return the top layer (which was set aside) back into the digester to finish composting and continue to add food scraps.

I'm in the process of installing a second digester. Similar to the traditional above-ground "three-bin" composting method, when one digester gets full, I'll start to use the second digester. After 6-12 months, all the compost in the first digester should be finished and ready to use.

DO Compost

Vegetable scraps
Grains and pasta
Fruit rinds and peels
Coffee grounds, filters
Tea bags

DON’T Compost

Oily foods
Dairy products
Other animal products
Pet waste

Viola... fresh compost in a can!


After you try it, show it off to other members in the
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posted in: Projects, Composting, bio-digester

Comments (19)

naturedude writes: Hello, I've done this, though I did drill more holes (all covered underground)and have a 80% food to 20%soil layer ratio. The worms aren't doing too well. And the food isn't decomposing very quickly (compared to my above ground compost). Should I just add more soil? It is winter at the moment around 5degrees celsius average.
Posted: 6:37 pm on January 19th
Posted: 3:18 pm on September 11th
AliceFulter writes: Very well technique
Posted: 6:01 am on January 26th
silaswren writes: Very creative work.. Really good
Posted: 12:33 am on October 10th
GretaGarbone writes: For the person who uses it for Doggie Doodoo, do you need to add anything to the composter? I compost veggies and fruits and I've heard that you can compost dog waste. Thanks.

Posted: 3:41 pm on February 11th
rocksmart writes: I have had one of these for the past two years and love it. I get beautiful black compost from it, full of worms. My yard has deep shade, however, so I spray painted my lid with flat black paint in order to help draw heat to it, and it keeps it more hidden. Works great. I only add garbage and a handful of leaves once in a while. I do recommend having two of these so you can keep adding while one is 'cooking'
Posted: 7:00 am on January 23rd
Posted: 12:09 pm on June 2nd
TexAllen writes: I think I have maggots in my composter. There are hundreds of little creatures moving throughout all of the compost that look like grubs. They are about an inch long and as fat as a pencil. There are also lots of 1-inch red worms about as thick as a pencil lead. I live just north of Dallas, Texas. I constructed the composter in mid-June. Despite feeding it regularly there has been no sign of life until last week. I assumed that the one-hundred degree plus in the shade daily temperature was responsible for the worms ignoring my composter. Then last weekend I noticed the grub-like worms. I found pictures of maggots on the web that look very similar to my grub-like worms. What should I do? Should I send the composter contents to the organic waste recycle (city compost site)?
Posted: 8:27 pm on August 30th
farmcurious writes: Funny, I created this exact composter, but for dog waste. I bought a five-gallon metal waste basket with a lid, drilled the holes into it, buried it and started adding poo. Unfortunately, now it's full and I'm thinking of burying a second one next to it. I also didn't add soil as I went along so I think maybe there weren't enough microbes working on mine. We'll see what happens with #2 (please pardon the pun).
Posted: 5:27 pm on July 6th
GardnerAries writes: I have a 30 gallon plastic barrel that's just perfect, why can't plastic be used for this?

Also, I'm on raised beds because about 8 inches down is caliche, which is a concrete-like clay. I broke a pick trying to bust it up. Is it necessary to go into the ground as shown?
Posted: 12:27 pm on June 22nd
LHardin writes: So how big a can is that?
Posted: 10:02 am on June 9th
yourownvictorygarden writes: Cayuga75: By not burying the composter in the ground, you are severely reducing the amount of surface area for the worms and other critters to get in via the holes. I would strongly recommend burying it.... even just a couple of inches would help. Plus, it would keep it from getting accidentally knocked over.

lisalisa545: Mine are in the shade half the day, then in the sun for the rest of it. The lid helps to keep the soil from drying out from the top, so you're OK there. The metal can get pretty hot if left in full sun, so if possible, opt for shade.
Posted: 1:51 pm on June 8th
lisalisa545 writes: Does it matter is the composter is in the sun or the shade?

Posted: 1:38 pm on June 8th
Cayuga75 writes: Hi1 I have a question: is it really necessary to bury the can in the ground? I am not bothered by critters and don't relish the idea of having to haul the compost out when it is done. How about if I just drill holes in the bottom, throw in a few worms, and water it from time to time?
Posted: 12:38 pm on June 8th
Kimi57 writes: Well this is OK for some but if you have dogs cats and other critters in the yard this can be a problem remember this can also call in some (mice)! EW!!! So if your thinking of this in your back yard remember you will have some furry friends! come and check it out!
Posted: 8:47 am on June 8th
CharlyeMac writes: I love this idea. I have had problems with my food scraps attracting rodents, especially a possum family. I like animals, but am a bit squeemish at rodents. I will have to recommend this to my friends.
Posted: 8:46 pm on May 28th
ChrisMcLaughlin writes: Very cool composter! You could also add other carbons like shredded newspaper in there if it gets a bit smelly.
Posted: 1:06 pm on May 26th
wscraps writes: BRILLIANT! Thank you! I have been trying to find ideas for composting, and this is a great one! Plus, I don't have a lot of room for composting and this will work wonderfully! YAY!
Posted: 9:07 pm on May 25th
MitHof writes: What a great description of how to create these valuable little composters! I loved the tip of writing the date inside. Thanks for taking the time to post this. I'll definitely be sending people here for information. (By the way, for those who don't have an electric drill, a leather awl and a rubber mallet will also poke the holes just fine.)
Posted: 2:13 pm on May 21st
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