A balanced input of green waste and FERMENTED human waste products are treated in a two-step process of lacto-fermentation and vermin-composting.

  • COLLECT INGREDIENTS — Obtain fresh, finely shredded wood clippings (for its molecule-building lignin) and mix with plant-based charcoal powder, wood ash, dolomite rock powder (for its trace elements) and living, local soil (introducing critters). Per person establish three compost beds each 1 by 2.5 m in size and piled up max. 40 cm high. Keep substrate moist and warm.

  • FERMENT & APPLY URINE — Collect urine in recycled milk containers and ferment with sauerkraut brine (pickled cabbage juice). After the month-long lacto-acid fermentation its pH value needs to go below 4 and turn sour. Only pH-tested urine is applied at a rate of 3 liters every third day over each compost bed (sized 2.5 m²). The charcoal and organic buffer will gradually absorb this stabilised ‘nitrogen tonic’.

  • BUILDING NUTRITION BUFFER — Layer up compost heap with ingredients, keep it moist and control acidity. Let microbes do their magic.

  • WELCOME THE EARTHWORMS — Ensure that pH value of compost bed is around 7 and release earth worms sourced by friends or online. Be patient until worms have done their work and migrating somewhere else. Analyze and evaluate the finished Terra Preta substrate before moving on.

  • FERTILIZE, PLANT & GROW — Apply Terra Preta fertilizer, about 10 liters per square meter of planting bed. Mix 10 to 20 cm deep and mix lightly with hoe. Don't flip it over or burry into the ground so that it retains its coherence and grow deeper over the years. Grow cabbage and other veggies on local soil with and without Terra Preta for comparison.

  • HARVEST, EAT & START OVER — Analyze crop for nutrients, yield and taste. Eat the produce and make home-brewed sauerkraut. Share experiences and learn from mistakes.


¹ Development Process and Possible Manufacturing Method, Notes from an excursion to Dr. Jürgen Reckin's Terra Preta garden on April 28, 2012 [German], Kathrin Ollendorf, Wendepunkt Zukunft, 2012.
[Accessed: 24.iv.2013]

² The Amazon, Unnatural Histories. TV documentary, BBC Four. The story of a far less natural Amazon is revealed — enormous manmade structures, even cities, hidden for centuries under what was believed to be untouched forest. All the time archaeologists are discovering ancient, highly fertile soils that can only have been produced by sophisticated agriculture far and wide across the Amazon basin. This startling evidence sheds new light on long-dismissed accounts from the very first conquistadors of an Amazon teeming with people and threatens to turn our whole notion of wilderness on its head.
http://www.youtube.com/watch?v=-YS8I6AZRfg [cue at 34:44 minutes]

Feeding Social Organisms

Making Terra Preta

Terra Preta provides regenerating, long-lasting soil fertility informed by recent insights on plant nutrition and the role of soil microbes. This ‘empathetic approach’ is guided by the practice of biologist Jürgen Reckin and scientific research at the Institute of Wastewater Management at Hamburg University of Technology and allows the conversion of human waste products into the food cycle in a responsible and safe way.

The system is based on a balanced input of green waste and human waste products that are treated in a two-step process ¹ of lacto-fermentation, followed by vermin-composting. Lacto-fermentation (widely used to preserve foods) is a biological anaerobic (airless) process that doesn't release any odors. Vermin-composting employs the digestion of earth worms which make nutrients palpable to plant roots.

An organic charcoal mix (containing finely shredded wood and ash) provides the buffer medium to host the micro-organisms and optimize the carbon-nitrogen ratio required for vermin-composting. The high black carbon content is characteristic for Terra Preta soils, which contributes to their amazing water retention and nutrition storage properties ² . Instead of using artificial (mineral) fertilizer, fully stabilized, fermented urine is used because it concentrates 80% of water-soluble plant nutrients like nitrogen, phosphorus and potassium delivered free of charge by the human organism day by day.

The Nutrients Recovery adapts the Terra Preta method that works best — using a minimum of resources — alongside full-time employment and with existing infrastructures. The main pre-requisite is time since it takes up to six months to produce Terra Preta black soil consisting of the following phases:

  1. 1) Lacto-fermentation of urine (ca. one month)
  1. 2) Micro-biological conversion of carbon and nutrients (ca. three months)
  1. 3) Vermin-composting (ca. two months)

Between each phase the developing substrate is observed and moderated to ensure the integrity of the final fertilizer. Depending on weather and local conditions this process will be sensitively adapted.