Aerated Compost Tea- Field Guide

Project Overview

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

Annual Reports

Information Products


  • Additional Plants: herbs


  • Soil Management: composting

    Proposal summary:

    There is a large amount of literature available on the production and use of compost teas and compost extracts for use in sustainable farming systems. The literature, however, tends to fall into two main categories: detailed academic studies often conducted in the laboratory that focus on very narrowly defined outcomes ("...reduction of foliar infection of pepper plants by Phytophthora Capsici [using] extracts from Iljuk-3 and shinong-8 compost.") or "How to make compost tea in a 5 gallon bucket" Youtube video. Our goal in this research is to produce a  manual that provides detailed instructions for ingredients, production methods, and application that can be used as a field guide by working farmers.

    With the passage of the Food Safety Modernization Act (FSMA), there is increased attention to all farm inputs. Many food retailers, wholesalers, and restaurants are moving towards requiring producers to be certified through the USDA for Good Agricultural Practices (GAP). While GAP certification is currently voluntary, it is expected that within five years mandatory certification will be put into place by either governmental or end user requirements. In this regards, a clear process for producing and using compost teas that objectively demonstrate their safe use will be essential. The Core problems that this research will address are:

    1. What is the exact process to be used in producing a safe compost tea under organic   standards?

    1. What types of on-farm and laboratory based testing can be developed to empirically   demonstrate that the compost tea produced is safe and will meet minimum GAP and   FSMA Standards?

    The March 2002 ATTRA publication "Notes on Compost Teas" offers an excellent overview of the issues involved in compost tea production. The work of Dr. Elaine Ingham is well documented, and the article lists many resources for additional study. Dr. Ingham is a prolific author and has much useful information at her website ( Much of the information available, however, describes the benefits to agriculture and even the biological mechanisms whereby microbes benefit crops. Very few  publications describe in great detail how a particular batch of compost tea is made and how very slight changes in protocol, materials used, or environment can change the resulting outcome. The medical community spends millions of dollars to assure standardization and extreme quality control in the production of microbes. The farming community, on the other hand, has very little information on the practical details that can make such a difference in the final composition of a brewed compost tea.

    This research will address this. We will document each aspect of production of compost tea, listing ingredients, environmental conditions, procedures, and other factors that could result in differing biological outcomes. As we modify our procedures or ingredients we will test for how these changes affect the quality of the compost tea.

    In addressing the need for quality control and the ability to quantify why and how a particular batch of compost tea is safe and effective, we are taking a dual level approach. For the purpose of this research we want to use one or more independent labs to quantify the amount and nature of microbes produced. These tests are expensive, averaging approximately $200 per test. There are very few labs that specialize in this type of testing for agriculture. Simultaneous to testing thru a lab, we intend to develop our own "on-farm" quality control measures, utilizing a microscope with visual counts of microbes. We hope to develop a reliable, consistent, "quick and dirty" procedure that farmers can be trained in that will give a basic indication of compost tea health and effectiveness. 

    This research will uniquely address one of the missing links in research on compost teas: the lack of component material specificity in most compost tea formulas. We will list specific information on all materials used. For example, most compost tea guides state:

    "Use 10 gallons of clean water"

    We will answer the following questions regarding this:

    1. What is the source of your water?
    2. Is it consistently available?
    3. Does it contain chlorine (from city tap water)?
    4. What method do you use to eliminate the chlorine? How long do you let it sit in a bowl? At what temperature?
    5. What is the ph of the water and the nutrient makeup of the water?
    6. If the water is highly mineralized (for example high sulphur) how do these minerals affect the compost tea?
    7. At what temperature do you have the water when mixing with other ingredients?
    8. What is the order of mixing the water with the other ingredients?
    9. What is the exact process used to mix the water with the other ingredients?
    10. What implements do you use in mixing? Does it make a difference if you use stainless steel or a wooden paddle? (for example)

    We intend to create this level of detail for all aspects of compost tea production.

    Project objectives from proposal:

    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.

    1. Identify the feasibility of using compost tea as a biological pesticide, utilizing naturally occurring microbes that are present on the surfaces of plant leaves as a base ingredient for compost tea.

    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.