Enriching Vermicast through the Use of Bokashi-Fermented Food Waste Inputs

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2022: $15,000.00
Projected End Date: 03/31/2025
Grant Recipient: Trefoil Gardens
Region: Southern
State: Georgia
Principal Investigator:
Melanie Jones
Trefoil Gardens


Not commodity specific


  • Soil Management: composting

    Proposal summary:


    The proposed solution for fixing eroded and degraded soil is finding ways to naturally and sustainably create new soil, while also revitalizing existing soil.  Bokashi is a relative newcomer to the field of nutrient recycling.  It involves the anaerobic fermentation of material by lactobacillus bacteria.  Many consider it more user-friendly than traditional compositing because the use of bokashi fermentation allows the farmer/consumer to utilize a wider range of food waste inputs (such as citrus, alliums, bone, fat, and other animal by-products) in the creation of the composting medium.  


    To that end, this project plans to investigate how using bokashi-fermented food waste to enhance traditional vermicomposting efforts can improve overall soil health in terms of increasing soil organic matter, biota, and nutrient density.  Hypothetically, the increased biological activity of the fermented food waste will be a benefit that will increase biological activity in the worm bin outputs.  These outputs will be used as soil amendments, via vermicompost, to introduce supportive biota that will enhance the soil food web.  Having healthy soil reduces the need for off-farm inputs.  Having healthy soil enhances the nutrient density of food and it results in improved yields for the farmer.  If the proposed hypothesis is correct, the fermentation of food waste could prove invaluable in the world-wide campaign to build soil and heal the land.

    Project objectives from proposal:

    As part of the project, Trefoil Gardens will establish food-waste collection sites at ten (10) of the neighborhood cooperative locations.  Participants will collect their food waste for a week at a time, before being retrieved.  One-half of the households will bokashi-ferment their food waste.  The other half will store their food waste in a similar sealed container but without fermentation. To attempt to account for the dietary differences of the included family units, the participating households will alternate their food waste storage methods on a monthly basis.  Therefore, each household will provide both bokashi-fermented and unfermented inputs over the course of the experiment.  In addition, while bokashi fermentation can handle non-vegan inputs (i.e. meat, bones, dairy, etc.), we are asking participants to include only plant-based food waste.


    The unfermented food waste will be fed to a continuous flow-through worm bin divided in half.  The other will be fed the bokashi fermented food waste, following the completion of its fermentation cycle.  Feeding will take place on an as-needed basis.  When fed, both sides of the bin will be fed the same amount of their respective foods.  The two sides will be separated by a divider with holes for the worms to migrate through should conditions in one area of the bin become unfavorable.  To help ensure a supportive environment for the worms, the average pH for both food waste inputs, fermented and non, will be monitored and recorded.  In addition, the pH of the top two inches of the vermicompost bins will be tested prior to feeding.  There will also be a pH test of the harvested material.  This will give data points for tracking the pH of the inputs and how the bin handles the pH of those inputs over time.  Once harvesting begins, quarterly samples will be sent off to a lab for a compost analysis along with a Solvita Color Interpretation test for microbial activity.  Following completion of the timetable, all data will be compiled into a report that will be presented according to the Outreach Plan.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.