Johnson-Su Bioreactor

posted in: Research, Video | 25

Quickly restore soil with this low-cost method developed in New Mexico

David Johnson is a molecular biologist conducting research as Research Scientist at the Institute for Sustainable Agricultural Research at New Mexico State University, Las Cruces, NM and an Adjunct Professor at the Center for Regenerative Agriculture and Resilient Systems at California State University, Chico, CA.

Dr. Johnson has been doing breakthrough work in regards to the efficacy of biologically diverse, fungal-dominated compost for carbon sequestration and improved soil health and crop yields. His method is called BEAM (Biologically Enhanced Agricultural Management). The composting system he devised with his wife Hui-Chun Su is called the Johnson-Su Bioreactor.

Compost is often erroneously thought of as fertilizer, a way of adding nutrients to the soil. BEAM compost actually addresses soil health through soil biology. It replaces soil microbes in soil that has been degraded and is lacking in soil life. Adding BEAM compost inoculants and following the soil health principles –using for example no-till or low-till practices, cover crops and other regenerative agriculture practices– revives the mutually beneficial symbiosis between soil microbes and plant roots. Quite quickly, the soil starts to recover, and striking improvements in crop yields and carbon sequestration occur.

David’s research in soil microbial community structure and function, has opened a window for viewing the interdependence between plants and soil microbes. Rebuilding a soil’s microbial community, population, structure, diversity and biological functionality will also provide a robust and practical mechanism to begin reducing atmospheric CO 2 within a regenerative agricultural system.

How-to for a No-Turn Composting System that produces a SUPERIOR, microbially-diverse and fungal-dominant compost. This compost can be used to restore biological functionality to soils from small to large farming operations and from simple to advanced agroecosystems.

Watch Jason Carter of Carter Farms in Eastover, SC, treat 250 lbs of cover crop seed with Johnson-Su compost slurry and plant with a no-till grain drill.

For more videos, see this Johnson-Su bioreactor youtube playlist

Subscribe to Dr. David Johnson’s youtube channel at

Get your dirt working with microbes, Taos News

25 Responses

  1. Joe Dino

    Is it possible to build a smaller one in say, a metal trashcan?

    • admin

      My inclination is to say no, as the dimensions are tailored to the need for the pile to heat up and then age for optimal microbial and fungal growth.

      • admin

        Just learned that the maker space in Las Cruces is experimenting with smaller scale versions of the Johnson Su Bioreactor for food waste! They modified the design, using the same wire structure and landscaping fabric, but making a narrow 3 feet tall pipe. They first collect composting materials including food waste, let it all dry out, then wet it and assemble.

  2. Alan Stuart Watt

    Hi there,

    Does Dr David Johnson think that adding biochar as a house for the microbes may be an added extra the will help to sustain the microbes?

    • admin

      Interesting question, Alan. It seems the combination of BEAM (boosting soil biology) and biochar (boosting soil carbon) could be beneficial, but in this blog post by ACRES Dr. Johnson warns that you have to make sure the biochar is made properly, a.i. not “raw”, and that if applied at amounts “over 15 tons per acre” it can become detrimental to soil health.

  3. Nathan p Shapiro

    I have a few questions.
    1. How do you empty the bioreactor at the end of the process? The wire frame and landscape fabric attaches to the pallet base in a video I’ve seen so it can’t be lifted up. The fabric is also wired to the wire frame so it would seem to be difficult to remove the fabric.
    2. If I don’t secure the frame to the pallet, can the bioreactor be made slightly conical so it can be easily lifted up and removed.
    3. If I can find some other method to keep the bottom of the pipe tubes secure for filling, like digging not-to-deep holes in the ground, and build the entire reactor on the ground would it work as well?

    • Owl McCabe

      1. To your first question:
      I have made so many bioreactors I have lost count. The trick in getting it off is in making sure you assembled it with taking it off in mind. Make sure the end of the fabric lines up with the end of the wire. That way when you are ready to use the compost, all you need to do it unsecure the wire frame from the base and remove the connectors that hold the ends of the wire frame ends together. You can then reuse the wire frame with the attached fabric for your next pile.

      2. To your second question:
      Actually, after the first few bioreactors, I quit attaching the wire frame to the base. It wasn’t really needed. As I mentioned above, all you need to do is unsecure the wire frame ends and pull the frame off the pile.

      3. To answer your third question:
      You MUST have the bioreactor on a pallet. It is the main reason this works. If you don’t, the pile will go anaerobic. The pallet allows air to go under the pile and up the tube holes making sure all the pile has access to air.


    Built my first bioreactor on 11/24/20 with a combination of wood mulch (well under 3/8″) , and leaves (including Oak leaves). The pile started at 80 degrees F and has slowly gone down to 60 degrees F. In other words, what happened to the thermophilic phase?

  5. Costas

    1. Can we use tap water that contains chlorine for keeping the content wet or chlorine will destroy the process
    2. Can we use only hay to make compost or should we use different kinds of plants?

    • admin

      Costas, rain or well water would be better, but if you have to use chlorinated tap water let it sit for a day before applying it to the bioreacor. To your second question: diversity is always better, but you can use what you have.
      I would also encourage you to join the Regenerative Agriculture Network Web Forum, hosted by the CENTER FOR REGENERATIVE AGRICULTURE AND RESILIENT SYSTEMS

  6. Marsha

    Is there information on a Johnson Su Bioractor in the midwest state such as Nebraska, or South Dakota when the temperatures drop and stay below freezing. The water pipes to spray daily would freeze. Would the bioreactor need to be in an enclosed area where it does not freeze? Could the system go dormant or would it die during the months when the temperature is below freezing.?

    • Scott Hortop

      Hi Marsha. I have done 15 batches with winter freezing in Ontario, Canada. Your question has been asked frequently but I have yet to read a well articulated answer. With a 3 month winter freeze, we have successfully produced fungal dominant compost with a Microbiometer F:B score of 1.7:1 in an 18 month window, loaded in the late fall and unloaded 2 springs later. Johnson and Su have asserted that we shouldn’t allow them to freeze but I have not heard them or anyone provide a technical explanation/justification of why they must not be let to freeze. My guess is that it is because the worms cannot migrate in the winter below the frost line due to pallet blockage and they freeze to death. I believe our modest F:B score is because we have not added worms to the pile in a timely way and in sufficient numbers. We intend to put 40+ worms in each batch in the spring and accept that they will freeze to death annually. We are also experimenting with 3 foot high piles without a pallet so that worms may escape to sub-soil safety as winter approaches. I would be glad to discuss this further with you or others if you wish. Scott

  7. Dean Moser

    I’m starting with new land in Tennessee and would like Dr. Johnson to contact me for me to get on a list as a startup to track progress in a wet environment.

    • admin

      Dean, I suggest you get yourself one the Johnson-Su BEAM Research & Bioreactor Registry at
      Dr. Johnson is watching this registry very closely and there is also a forum at the same website where you can become a member. That way, you can become of this vibrant network and find out what the steps are to become a possible research partner. Thank you for your inquiry and best luck!

  8. Joe

    Question 1: What is the best way to track moisture levels of the Johnson Su bioreactor?

    Question 2: What results would you exspect to see if alfalfa was the only thing put into the bioreactor?

    Question 4: Other than alfalfa, would you rather add more items to your bioreactor? If so, what?

    Question 3: If using alfalfa or anything else, what size would you chop/shred these items down to?

    Question 4: Where is the best place to learn how to raise the brix score in our food?

  9. Dale Fulton

    Hello Johnson-Su,
    Please advise whether the bioreactor will break down or consume plastic particles during its active cycle?

    thank you
    DH Fulton

    • admin

      Hi Dale,

      Dr. Johnson replied: In the analyses done on my compost, we have seen microbes that break down plastic. However, the process is quite slow so that the breakdown of plastic is negligible within the time frame that these bioreactors operate…

  10. Wittocx


    we built several Johnson-Su bioreactors.
    The oldest one (installed in May 2021) is declining both in µg/g (micro-organisms) and f/b ratio (measured with the MicroBiometer), up from 1200 to 670 and from 2.6:1 to 1.3:1 respectively.

    Two questions:
    1° what are possible reasons for this decline? (e.g. is it possible the organic material available to the micro-organisms has been largely consumed?)
    2° can we jumpstart new bioreactors by mixing the above described compost with new organic material?
    If yes, at which ratio? (e.g. 1/4 or …) Would the thermophylic process at the start eliminate the introduced micro-organisms, or do they just become inactive and resume activity after the temperature has re-settled to ambient?

    Many thanks in advance for your reply/insights on the above.
    J. Wittocx

    • admin

      Hi Johan,
      Hui-Chun and David don’t recommend using the MicroBiometer, it’s better to do microscopy.
      They have done analysis of bioreactors at 13 months and two years old respectively and suggest that the way to keep the compost going at that stage is to reuse the materials to build a new one:
      Build a smaller structure (reusing the same construction materials if those are still in good shape) ~2.5 feet tall, same diameter. Shovel the mature compost and worms into the new bioreactor bin. Set up the same sprinkler system, perhaps cut back a bit on water if needed, to maintain 70% moisture content. Top it off with shredded hay or alfalfa. That way worms keep going and quality is maintained. At this stage it is basically like a vermicompost, but you don’t feed it.
      Hope this helps!

  11. Betsy Kettle

    What is the theory behind keeping the surface damp? Is it to continually capture new fungal spores or just keep the growing media moist? Why a period of a year? Is this how long it takes to bring the fungal community to “fruiting stage” so there are living spores to spread? Will the fungi spread through its bits and pieces or can it only spread through spores?

  12. Judy Sudduth

    Can you store what you don’t use or do you have to use all the compose when it’s ready?

    • admin

      Yes, the finished compost can be stored although not indefinitely. You also want to keep it moist and avoid extreme temperatures to keep the microbial community alive.

  13. Mar

    After taking a workshop to learn the process of building a JS-Bioreactor, I’ve built a half-size reactor near my garden. It seems to be working well and I plan to start using it in July, because that is the one year mark. Now my question is: In a small, fenced area with six full sized goats, how many size reactors would be needed to utilize all the damp-straw muckings? Is there a square footage calculation to figure this out? “Three truckloads” … what size truck?

  14. Joern

    under summer conditions, using small green fresh woodchips, what time can the thermophillic stage last ?

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