Aerated Compost Tea- Field Guide

Final Report for FW15-037

Project Type: Farmer/Rancher
Funds awarded in 2015: $14,560.00
Projected End Date: 12/31/2017
Region: Western
State: New Mexico
Principal Investigator:
Minor Morgan
North Valley Organics
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Project Information


This project began in 2015 after a review of literature revealed that little information was available about how the Food Safety Modernization Act (FSMA) would affect the on-farm production of compost tea by farmers. While there is a wide range of literature regarding the uses for compost tea and some literature about the effectiveness of compost tea, there is little concrete information on the specific steps required to make a high quality compost tea. In addition, we could find no literature that specifically addresses FSMA and the production of compost tea. FSMA itself discusses "agricultural products of animal origin" which can include compost and compost tea and discusses 2 methods of making compost that are acceptable under FSMA. However the regulations do not list a specifically approved process for making compost tea.


Over a 2 year period we developed a process for making compost tea that, we believe, meets FSMA Standards. An important outcome of this research was the development of 3 specific assessments that farmers can complete to help them understand all the issues relevant to making a safe compost tea.


We also trialed several sources of compost and several variations of making compost tea and listed the results of these trials. The main 2 products resulting from this work are an 85 page Monograph "field Guide" and a set of PowerPoint slides. Both of these are available as a pdf document.


We believe that this information will be useful to farmers not only to help them become compliant under FSMA, but also as an important component of an overall food safety plan for the farm.


In January, 2011 the Food Safety and Modernization Act (FSMA) was signed into law, with a 5 year review period for receiving feedback and modifying the regulations. FSMA covers a wide range of issues regarding food safety and agricultural production and consists of thousands of pages of regulations, rulemaking, etc. FSMA was promulgated by the Food and Drug Administration (FDA) and grants broad authority to the FDA to regulate its Standards, including regulating on-farm production activities.


One part of FSMA- The Final Rule for Produce Safety- was the focus of this research. The Final Rule was published in November, 2015 and went into effect in February, 2016. There is a timeline for beginning of enforcement activities that ranges from 2016-2020. The Produce Safety rule establishes: "Standards for the Growing, Harvesting, Packing, and Holding of Produce for Human Consumption". In subpart F of this rule, compost and compost tea is addressed.


In the last few years there has been a resurgence in interest in biological farming- maximizing the natural biologically based processes that occur on a farm, to the benefit of the farmer and the farm ecosystem. Elaine Ingham, the Rodale Institute, Cornell University College of Agriculture and the Sustainable Agriculture Research and Education program (SARE), to name a few, have long championed the critical role microbes play in soil health and improving the farm eco-system.


New research is emerging about how these microbes are present at every level of plant production and play a critical role in plant growth, carbon cycling, pathogen suppression and a healthy environment. The specific focus of this research was on developing an on-farm process for making aerated compost tea that meets the newly promulgated Standards for "biological soil amendment of animal origin" under the Food Safety and Modernization Act (FSMA). We outline what a farmer must do on his own farm to meet FSMA standards for compost tea safety.

Project Objectives:

The following have been identified as objectives for this grant. All have been met:


  1. Identify by name and source all components used in compost tea production.


  1. Identify quantities, how quantity measured (weight, volume, etc), storage requirements and other parameters for all materials used in compost tea production.


  1. Identify by description all equipment and implements used in compost tea production.


  1. Identify each step in the process of brewing compost tea and describe in detail all parameters involved.


  1. Create a pictorial and/or video documentation of all procedures and materials used.


  1. Identify laboratory facilities available for testing including testing of dry compost, water source and finished compost tea.


  1. Identify key assays to be used in laboratory testing for each material (compost, water and compost tea) and include copies of reports from each lab.


  1. Identify and describe an "on-farm" simple process to use in identifying major components (microbes) of a finished compost tea using visual identification under a microscope.


  1. Identify how timing and temperature affect the production and application of compost tea.


  1. Identify how various methods of application (i.e. spray, side dressing, injection in drip tape) influence the effectiveness of compost teas on vegetable crops.


  1. Particularly for spray application, determine if and how spray orifice size, orifice pattern and output pressure affect effectiveness of compost tea.


Click linked name(s) to expand/collapse or show everyone's info
  • John Garlisch


Materials and methods:

There were three phases to the project. Phase one involved doing the research on FSMA and locating laboratories that were able to complete the compost tea evaluations that met the Standards for microbial safety published by FSMA. This turned out to be quite difficult. We were not able to locate any laboratories in New Mexico with this capability. We were able to locate 2 laboratories in California but this then required us to develop a process for gathering samples and shipping to California in such a way that the sample was not compromised.


Phase 2 involved developing a series of assessments for farmers to use in evaluating the readiness of their farm to go through the rigorous process of "validation" as required under FSMA. We developed three instruments that will help farmers in this regard: 1) An overall Farm Assessment that requires the farmer to think through why and how they will use compost and compost tea on the farm, 2) An assessment that outlines all the areas the farm will need to address once they decide to make FSMA compliant compost tea, and 3) A "Step-By-Step" production manual outlining the process we follow in making compost tea.


Phase 3, concurrent with Phase 2, was the actual development of the process and documenting each step involved in making compost tea. Because this grant is somewhat research oriented, we used three different brewers, typical of what might be found on a small scale farm: 5 gallon, 10 gallon and 40 gallon. We also trialed three different compost sources, typical of what might be found on a small scale farm: chicken manure "backyard" compost, horse stable compost and commercially produced compost. We made teas from these different composts and tested them.


Finally, at the completion of our project, we developed a design for a 40 gallon brewer that is very easy to clean and overcomes many of the design flaws of commercially available brewers. This brewer is low cost, easy to use with parts readily available to any farmer.

Research results and discussion:

As a result of this research we have developed materials that will help farmers by:


1) Raising awareness of what constitutes safe practices for making compost tea.


2) Presenting a self evaluation process that will inform the farmer of potential risks on their farm.


3) Outlining the variables in field production of compost tea to assure safety.


4) Listing various parameters needing to be addressed when making compost tea.


5) Documenting a "step-by-step" process for making safe compost tea.


6) Listing specific resources for testing compost tea samples for pathogens.


We developed a "validation" process that we feel meets the standards set forth by the FDA for a "scientifically valid controlled physical process" for making compost tea. We documented this process in the "Field Guide" using photographs and illustrations. The appendices to the "Field Guide" contain much useful references and detailed information.


The FSMA is vague on what the exact requirements are regarding use of compost tea. It appears that teas fall under the generic category "treated soil amendments of animal origin" and therefore can be regulated by the FDA. At our farm we have chosen to adhere to the microbiology Standards as a precaution and to demonstrate a deeper commitment to food safety at the farm. Ultimately our motivation is to create a "culture of safety" at our farm to assure our customers we are doing everything possible to bring them a safe product.


Having "bitten the bullet" and decided to take the extra time and trouble to document our tea brewing process and create a "validated" set of practices, we have discovered many important lessons along the way, lessons we would not have learned if we had not decided to go down this path. Lessons not only about safe farm practices, but a deeper appreciation for the "life in the soil" that is the true richness of the farm. We are now experimenting with "designer" composts where we hope to isolate and multiply the probiotic microbes that are plant specific. We will use teas made from these composts to inoculate plants in the same family. We are learning about bacteria that exist on the leaf surface that help plants process nitrogen from the air (Azotobacter Vinelandii) and bacteria that exists in the soil that help roots process phosphorous (Azotobacter Chroococcum).

Participation Summary

Research Outcomes

No research outcomes

Education and Outreach

Participation Summary:

Education and outreach methods and analyses:

Our outreach efforts have been extensive. We initially formed a "Brain Trust" whose purpose was to advise our research but also be a conduit for disseminating information. John Garlisch is the Bernalillo County Extension agent and will have numerous venues and opportunities to share this information. Walter Dods is the owner of Soilutions which is the only compost supplier approved for organic use in Albuquerque. He will be able to share this information with his customers and at other venues. Matthew Draper is the assistant farmer here at North Valley Organics and works with other young farmers his age. Through his contacts we expect this information to reach a younger audience. Fred Koster is a farmer and microbiologist who has many professional contacts.


In addition, Minor Morgan is working with the newly created Soil Health Division of the USDA (NRCS). We made a presentation on our initial findings at a USDA sponsored workshop in Lordsburg, New Mexico on November 1, 2016. Minor is scheduled to participate in a national webinar on soil health sponsored by the Soil Health Division in June, 2017. Through these and other activities we believe we have an excellent opportunity to share the information far and wide.

Education and Outreach Outcomes

Recommendations for education and outreach:

Potential Contributions

The use of compost tea as a component in sustainable agriculture can benefit farmers by being:


  1. Economically viable. With a deeper understanding of production methods for making compost tea, farmers can make their own "on-farm" teas that target nutrient deficiencies, disease vectors and pest pressure. After initial investment in a commercial compost tea maker and a good microscope, there is little else required (besides knowledge and time). By customizing compost teas, farmers can save on fertilizers, pesticides and fungicides.


  1. Environmentally sound. Because compost tea is based in the biological processes of nature versus chemical processes, compost teas can replace harsh chemicals used as pesticides and fungicides, thus contributing to the overall environmental footprint of a farm.


  1. Socially responsible. Because no dangerous chemicals are used, compost tea production creates a safer work environment for farmers, interns, students and others involved in farm operations. By requiring a close attention to the biological processes involved in creating high quality teas, farmers are learning to be good stewards of our natural resources and learn respect for the complex interdependence of all life forms.


The major benefit to incorporating compost tea into a farm operation is to "super charge" the microbial and biological processes that are already in play on the farm. Uptake of nutrients by the plant, higher disease resistance and lower soil pathogen levels are all documented benefits in using compost teas. Economic savings in reduced fertilizers, insecticides, fungicides and pesticides translate into real dollar savings.

Future Recommendations

We learned a great deal during this research. However with every question we answered we generated 2 more. Some of the possible areas for research are:


  1. "Designer" composts. Is it possible to control the waste stream in creating a compost such that you target microbes that are unique to a specific class of plants? Will a compost made from waste streams from plants only in the cucurbit family, for example, produce a compost tea containing microbes that repel insects that attack the cucurbit family?


  1. Are there other methods for extracting microbes from compost that may be more efficient than brewing? How does "extracting" differ from "brewing" in the production of compost tea and are the benefits of extracting equal to brewing?


  1. For large operations, both brewing and extracting with the idea of directly treating soil or plants, can be daunting. What is the level of benefits to crops and the soil of simply inoculating seeds rather than the plant or soil? Inoculating plant starts for transplant?


  1. We are just now starting to fully understand the role of plants and the microbial life in the soil as it relates to carbon sequestration, and the potential for agriculture to become truly regenerative for our planet. What role does compost and compost tea play in restoring the soil to the level that plants can become a viable option for carbon sequestration?


  1. The proportion of bacteria to fungi in the soil is emerging as a critical area of study. What role do fungal based soils play in the farm ecosystem and how can compost and compost tea be used to move our soils to a more fungal dominant composition?

Information Products

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.