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

Progress report for FS22-344

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
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Project Information

Abstract:

 

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:

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.

Research

Materials and methods:

6/28/2022

Procure materials, assemble equipment.

8/28/2022

Worms added.  Composting initiated.  100% worm loss within 48 hours.

2/23/2023

Second attempt. Installed worms into worm bins.  Allow a week to establish before starting treatments.

3/31/2023

Begin scheduled batches of bokashi fermented garden waste bi-weekly.

4/14/2023

Add materials to worm bins per methodology. Begin testing pH, buffering as needed, prior to feeding.

8/4/2023

Continue adding materials to worm bins per methodology. Begin testing pH, buffering as needed, prior to feeding and send sample to Logan Labs for testing. (Quarterly moving forward.)

12/4/2023

Continue adding materials to worm bins per methodology. Begin testing pH, buffering as needed, prior to feeding and send sample to Logan Labs for testing.

4/6/2024

Continue adding materials to worm bins per methodology. Begin testing pH, buffering as needed, prior to feeding and send sample to Logan Labs for testing.

8/4/2024

Continue adding materials to worm bins per methodology. Begin testing pH, buffering as needed, prior to feeding and send sample to Logan Labs for testing.

12/1/2024

Continue adding materials to worm bins per methodology. Begin testing pH, buffering as needed, prior to feeding and send sample to Logan Labs for testing.

3/1/2025

Schedule field day with Cooperative Extension.

4/1/2025

Complete sampling and data entry.

4/18/2025

Presentation Prep

4/25/2025

Compile reports, publish to webpage, develop print materials, plan field day

5/25/2025

Field Day- demonstrate methodology and present findings

Ongoing

Collection of materials, fermentation of some, and worm bin maintenance.

   

 

Narrative of Challenges

 

The first challenge our team encountered was the loss of our worm population. Our first attempt at populating the worm bins, which are located in one of the farm’s greenhouses, began in August.  Conditions in the greenhouse became too warm during the time when the population was getting established.  In addition, water was added to the substrate material, which contained an excess of nitrogenous material - specifically rabbit droppings and coffee chaff from the roasting process.  Together the moisture, heat, and nitrogen initiated the composting process, further elevating temperatures, which caused the total loss of our first batch of worms within 48 hours.  

 

Our second attempt at populating the bins, which was initiated in February, has been a success.  However, water access is limited at the site in the winter months, while there is no access to electricity for lights or fans.

Successes

 

This project prompted the successful construction of both a greenhouse and a large, roughly 2’x2’x8’ worm bin.  The second worm population has become established and appears to be thriving.  Feed material processing is underway as are climate mitigation techniques to manage temperature concerns as we move into the warmer months.  Solutions being pursued are high albedo ground cover to reflect solar energy, and a solar powered fan system to help maintain consistent conditions..

 

Current State of Affairs

 

Currently, a  55 gallon barrel of garden waste is fermenting with bokashi inoculated bran.  The worms in the bin were left to acclimate to their surroundings, which is proving successful.  During this period, small ants have attempted to colonize the bin, which suggests the moisture level was too low.  The ants do not appear to bother the worms, but they do function as competition for food.  

 

Anticipated Next Steps

 

Worm bin moisture levels will be maintained at a higher level to deter ant colonization.  Baseline samples of the casting material will be sent to the laboratory for testing.  When the barrel ferment is ready, its pH will be checked and buffered, if necessary.  

 

As we enter the testing and comparison stage, a fresh sample of garden input material, harvested in advance, will be fed to the non-bokashi, control, side of the bin.  The bokashi-fermented inputs will be utilized on the experimental worm populations.  Our team will pull castings samples every three months, from each side of the bid, going forward and will send to the lab for testing and comparison.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

This project is still currently under work

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.