Designing a New Compost Bioreactor | DESIGN SPECS and QUESTIONS ANSWERED

Designing a New Compost Bioreactor | DESIGN SPECS and QUESTIONS ANSWERED

I set out to iterate and improve the traditional Johnson-Su Bioreactor design to make it easier to make compost. In this video, I show the new composter design and go over the reasons why I tried to improve the Johnson-Su bioreactor. The new composter doesn’t use any plastic and should last a very long time. Overall Johnson-Su bioreactors are a great way to make a lot of high-quality compost in a small space. They are also an easy way to make compost. Build the bioreactor, fill it, and then wait for compost. More on the new bioreactor:

Build a Johnson-Su Bioreactor:

✔️Check out my new podcast is In Search of Soil. Watch full interviews and Subscribe –

✔️ Follow Diego on IG
Growing in Vista, CA (Zone 10a) – Elevation 397ft – Latitude 33N

Podcasts by Diego Footer:
▶️ Microgreens:
▶️ Vegetable Farming:
▶️ Livestock Farming:
▶️ Modern Farming:

My Online Courses:
🌱Learn how to start a Profitable Microgreens Business
🐔Learn how to raise Pastured Poultry, Pigs, and Cattle as a business in the Pastured Profits Course –

🛠 Small Farm Tools
✔️ Follow PaperpotCo on IG
🎙Learn more on the podcast 🎙

🛒 Support my content while you shop at Amazon:


Diego Footer


What do you think?


Written by Aleksandar

Video MakerContent AuthorYears Of Membership


  1. Thanks for posting this video! Is there any concern about co2 pooling in the center ring since it is heavier than air and there is no way for it to escape through the bottom?

  2. I had these same ideas. I never knew what to search to find this subject. A bioreactor with a 12 inch center and a 36 inch outside diameter would have the same principle. As long as you were at least 36 inches tall. I built one march first 2020 and with leaves and grass and some coffee grounds it composted very fast. The best part was that it filled itself with worms quickly. I am going to go woth the design you just explained and am sure with 2 systems I will be able to harvest 20 to 50 pounds of Alabama jumper worms by just sifting through the piles. At $40.00 to $50.00 a pound for these worms I will make enough money to finally be fully independent. I have a farmer I once worked for and was fired for thinking out loud more often then he liked. He was certainly an Alabama jumper worm hater because of their destroying capacity. I will not mind losing a few thousand dollars just to fill his garden and home foundation with them. I fugure the act of revenge is much better than being selfish keeping profits from sales. Did I mention that I really dislike this man ? 😁

  3. I have been doing that diego, also inspired on the coments on your video!!! Its been a blessing!! But i opted for smaller with just a single pipe in the center! To ensure the air flow… no need for bottom ones to increase air flow worms did colonise and everything is flowing really well, im living at the caribbean and i have broke down palm and sawdust!!! Withing 4 to 5 months!!! But i believe thar weather and biology does add to it!

  4. I'm thinking of building a similar bioreactor. But with welded fence, and cage clips to hold it in a circle. No bottom. I will hold the rings in place, at the bottom with long, homemade ground staples, like the ones you would use for landscaping fabric. But mine are about twice as long and made from coat hangers. I think, once it's filled, the top should hold itself. I'll let you know how it goes.

  5. While I like your Idea of making it easier some questions came up.
    Dr. Johnson I think mentioned that after the heating process is over it is ok if the spacers collapse.
    I was kind of luggish watering my Bioreactor on ja regular basis. I think with your design watering or keeping it moisture is much more crucial to keep it going.
    Another aspect might be changing temperature. With the Johnson-Su design I think there is a better chance for the biology to get trough cold conditions. Maybe if you put some cover over the inner space in winter time you can keep temperature up for a while with your design.
    Have you thought about it?
    Also what makes me a bit uncomfortable watching. Dr. Johnson and his wife went public after some time of trial and error or scientific research. You bring it up like an instagram post.

  6. Only things I would add are wire over the top of the air tube so you can't accidentally fill it when loading and an easy to open front for the outer ring to empty it out when fully composted. Going to use this design!

  7. I suspect it's by design, but a 25 foot standard roll of wire, after cutting 6.25 feet off for your inner circle leaves 18.75 feet for your outer. That's 5.96 feet for your outer and 1.98 inner.

  8. Design flaw potential: The lack of wrap covering will make it very difficult to maintain 70 percent moisture. Also the smaller pipes create in effect a more solid mass for necessary heat buildup- that is three foot by three foot minimum. Your new design only gives a two thickness in the one direction effectively due to the larger inner air core. 1/2” hardware cloth would be superior to 1” chicken wire as for holding in/out debris.

  9. What would be the best hight of the bioreator? How long does the composting process last? Can we add worms when the heat goes down? Thanks for the video. Great information.

  10. I use potable water grade pipes, netting, and tanks for aquaponics. I use the same for composting materials. HDPE is completely inert. It has zero detectable chemical leeching.

  11. Very cool. I’d wonder if you could skip the chicken wire if you were to replace the concrete mesh with 2×4 welded wire. I’ve used this to keep my hot pile tidier and there’s still minimal spillage…I’d guess even less with a static pile.

  12. interesting cant wait to see the next video of it in action. i saw the idea on rob bob's channel , linked to you. he is local i follow, now i have to build and try it out.

  13. Obrigado
    Como o vídeo pode ser visto em todo o mundo. Visto por imensas pessoas que não sabem. Inglês. Talvez fosse positivo – além das palavras – agir na prática

  14. Too much work!
    More importantly, it is the human tendency to overthink, and overwork. To work to find a workable human solution to our human dilemma, that must be workable of course because we are human!
    All the while we completely discount the fundamental fact that the human animal is Of and dependent on the natural world.
    And there isn’t one single detail that nature hadn’t already figured out long before we showed up.

    Chop and drop in a rural setting.
    Amending or inoculating the area with soil microbes and mycelium to start is a good idea because most soils lack at least some as a result of human destruction of habitat, overconsumption, and the resulting heat/drought/fires etc that our activities are causing, and urban soils are typically dead, completely lacking these critical little workhorses.
    Then just let nature do the rest.
    An ecosystem is cyclical in all ways, if we perpetually take it’s building materials away from it, eventually it will go barren and die.

    Layer in an urban setting.
    Method one:
    Use well chopped material as bedding mulch. Disturb or flip occasionally for more soil contact and faster breakdown.
    Method two:
    Dig out a random shallow spade of soil in a bed, 3-6” deep and big enough to hold the material. Pour in kitchen scraps, or pulled weeds(no seeds!), or a random dead bird.., and cover by replacing the removed soil. Give it a pat and walk away!
    Usually within a few weeks the soil biology will have consumed the gifted smorgasbord and returned a gift of richer more nutritious soil that will in turn feed the plants.
    This is my favorite method, my “Touch it once and done” minimal time and effort method that over time gives me the sweet richness of a healthy soil biome.
    Chocolate cake soil!😊

    I want to spend my garden time nurturing my plants, being in harmony with nature.
    Not screwing with some ugly chicken wire contraption in my garden reminding me of the filthy, industrialized, increasingly dead world we’ve created.
    All life that exists in sum Is
    human habitat.
    All gardening- all nature- all life,
    see that it is all the same thing; life. And life depends on life.
    What are the origins of life?
    Water, and soil.
    Feed the soil biology.
    It will in turn feed your entire garden as more and more species discover the Life you’ve created there.

  15. Excellent presentation! I was familiar with the JS bioreactor before but have a better sense of the process after viewing your videos on the system. Plan on incorporating them into my urban San Diego garden soon.

  16. Thank u Diego. Great content. Is there a min volume you should consider? Was thinking about building a seven feet diameter one with a foot wide tube in the middle.

  17. First rate presentation. I like how you show your data to back up your design. I'll definitely have to build one of these but it won't be until may or later because it's cold and snowy here now. Look forward to the build video. Thank you

  18. A 6' wide pile seems very big compared to a regular 3 to 4' pile. Would a 1' center cylinder suffices, so that the outer circle is still 2' which adds to 5' in diameter? 1 1' center circle seems big enough for air to freely flow.

  19. I like how you have adapted the Johnson Su Bioreactor and came up with a version 2.0. I’ve been thinking about going more square/rectangular. Thanks for your contribution. Much appreciated Diego. 🙏. Also very grateful for Dr. David Johnson and his wife, the originators of the Johnson Su Bioreactor; their advanced biological expertise, original design concept and testing done to prove that this produces valuable fungal rich compost. Such a huge contribution in my book. Excited to see how your reactor, design upgrade, functions. Looks much easier and faster to build, fill and appears to possibly stay aerobic further along in the process. Collecting, preparing and filling these monsters sure take a bunch of time. I have to work on that part, especially because I plan to process many tons of leaves in the years to come. Thanks again 🙏😊

  20. How about just opening up the circular construction and making it a linear wall 18 to 24 inches wide. Could do rows of it hundreds of feet long.

  21. For the original design, based on the 1' air penetration rule wouldn't you only need one small pipe in the middle of a 4' diameter ring (1' from the inside and 1' from the outside)? are the other 5 pipes just to 'increase' the amount of air available or something?


Greenhouse Design Greenhouse 2021, 03.01.2021,

Greenhouse Design Greenhouse 2021, 03.01.2021,

Agricultural Practices | Soil Preparation | Crop Production and Management | Don't Memorise

Agricultural Practices | Soil Preparation | Crop Production and Management | Don’t Memorise