Compost Tea for Disease Management in Horticultural Crops

2005 Annual Report for LNE03-181

Project Type: Research and Education
Funds awarded in 2003: $147,956.00
Projected End Date: 12/31/2006
Matching Non-Federal Funds: $6,933.00
Region: Northeast
State: Pennsylvania
Project Leader:
Paul Hepperly
The Rodale Institute

Compost Tea for Disease Management in Horticultural Crops


The goals were to: 1) evaluate aerated compost tea (ACT) for its ability to enhance the health of horticultural crops and 2) educate potential users on its production, application and efficacy.

Field trials were done on 3 collaborating vineyards and at The Rodale Institute. Information on ACT was outreached via farmer field days, fact sheets, website and scientific and grower publications.

Objectives/Performance Targets

1) Of the 30,000 people exposed to and 120 people engaged in this SARE project, 50 farmers will adopt ACT within two years of the experiment.

2) Fifteen vineyards will incorporate ACT into their management practices within one year of the field day. Ten will permanently adopt ACT and serve as a model for the other sustainable vineyards.

3) At least 10 extension agents will permanently incorporate ACT practices into their recommendations upon review of research and attending field days. They will able to easily provide ACT production and application information, research results and contact information for equipment and ingredient suppliers.


Our performance objectives were predicated on ACT practice efficacy proving out giving positive and consistent results. However, our results were mixed for ACT efficacy. As such, we altered our plan to outreach our information without any recommendation to use it. In fact, we recommended a wait-and-see approach on the use of ACT until increased efficacy and consistency could be demonstrated. We did not conduct economic analyses as originally planned, as the practice did not pass efficacy standards for recommendation at this time. None of our collaborators adopted the ACT practice.

During the last year, we developed a popular grower publication in Biocycle and a scientific publication for Compost Science and Utilization. We also asked and received an extension to finish the scientific publication edits and finalized submission. These and our other activities have allowed us to surpass our targeted audience with our message on ACT.

We found E. coli associated with ACT in 2003 and by eliminating molasses in our mixture eliminated E. coli dangers in 2004. Our collaborator, Patricia Milner USDA, corroborated our E. coli results during this last year. This substantiates fears of potential danger in ACT related to pathogenic bacteria and the precautions needed to avoid these safety pitfalls.

Impacts and Contributions/Outcomes

We could not follow our original projected message to recommend ACT based on the inconsistent and weak efficacy found. We did, however, meet our objectives of informing farmers, Extensionists and researchers of our results and their significance. A positive result of this is greater awareness for farmers, Extensionists and researchers that this technology is not ready for recommendation and is in need of further development. This both prevents early adoption of a technology which is not ready and also helps to steer efforts toward improving it. Our research suggests that many of claims on the efficacy of compost tea are exaggerated and cannot be proven out by unbiased research. This lets the farmers and the greater community know that "let the buyer beware" in regards to the claims of product manufacturers.