Our DIY Johnson-Su Bioreactor

In our pursuit of more sustainable and regenerative farming practices, REGEN BEN suggested we needed a Johnson-Su Bioreactor—this composting system that not only enriches the soil - improving soil health. Monty decided to build our own version of a Johnson-Su Bioreactor that worked with the resources we already had on the farm.
We used a recycled IBC (Intermediate Bulk Container and filled it with a mix of:

  • Worm Casts: From our existing vermiculture setup, rich in beneficial microbes and nutrients.
  • Horse, Cow and Chicken Manure: From our animals and our neighbours
  • Leaves: Fallen leaves from our farm’s trees, a perfect carbon-rich material.
  • Lawn Clippings: Fresh green waste that adds nitrogen and helps balance the compost.
  • Soil: To introduce essential soil microorganisms and structure.
  • Green Waste: Plant trimmings and other garden waste from our fields.
  • Bokashi Kitchen Waste: A fermented compost from our kitchen scraps that accelerates decomposition and enhances microbial activity.
  • Maize Silage, Straw and Hay

These materials made a good mix of carbon and nitrogen, combined with the microbial life already present on our farm, which helps our compost break down in an optimal, nutrient-rich way.


How Our Bioreactor Works
The beauty of the Johnson-Su Bioreactor is its simplicity and low-maintenance nature. Once filled, the system requires minimal maintenance. We fitted our IBC with vertical pipes to ensure the compost stays aerated without needing to be turned, which is important for encouraging aerobic microbial activity.
We keep it damp but never waterlogged. This balance helps the composting process over the course of several months. The microbes and fungi in the mix slowly break down the organic matter, transforming it into biologically active compost that is teeming with life.
The main use has been to brew compost tea, aiming to unlock even more potential from our biologically rich compost. We’re expecting big benefits, including:

  • Healthier Soil: Boosting microbial life to improve soil structure, nutrient availability, and water retention.
  • Stronger Plants: Enhancing plant immunity and disease resistance, naturally supporting vigorous growth.
  • Faster Application: Delivering nutrients and beneficial microbes quickly and efficiently over large areas via foliar sprays and soil drenching.
  • Sustainability: Reducing our reliance on external inputs by recycling farm waste into a cost-effective, natural fertiliser.

We’ll be reporting back once we have measurable results to share. Stay tuned for updates as we refine this regenerative method and observe the impact on our farm!