Compost Extracts Viable Alternative for Managing Weeds


Weeds are the bane of organic farmers—competing for water, space, light, and nutrients. Not surprisingly, in OFRF’s 2015 nationwide survey of organic farmers, research into effective weed management techniques emerged as a top priority.

With the support of two grants awarded by OFRF, Dr. Gladis Zinati, an Associate Research Scientist at the Rodale Institute, has been evaluating the effectiveness of chemically- and microbially-designed compost extract (CMD-CE) in weed suppression. The first grant in 2015 helped fund the laboratory research. In 2016, additional funding from OFRF was used to test lab results in the field.

Zinati and her team partnered with Aimee and John Good at Quiet Creek Farm CSA in Kutztown, Pennsylvania to evaluate the impact of using compost extracts to reduce weed pressure, soil degradation, and yield losses of field-grown organic cabbage, as well as the germination-inhibitory compounds of DCE. DCE is the liquid version of compost, rich with plant nutrients and microorganisms.

Results from the project indicate that the application of compost extracts can be effective in managing weeds and may be used as an alternative approach to mechanical cultivation, In addition, the use of compost extracts has the potential to reduce soil compaction and produce comparable crop yields to the standard grower’s method. The approach of using CMD compost extract can benefit all organic vegetable growers, especially new and younger growers facing financial, labor, and/or equipment limitations.

Outreach on the project has been extensive, including demonstrations, hands-on experience, and dissemination of results to growers and university students. Along with Dr. Zinati, Aimee and John Good demonstrated the use of designed compost extracts as one tool in the tool box for weed management and no-till production for organic cabbage production. The information and results were shared with visitors at several field days. 

Read more about the project in the final report.

A project-related article is posted on Rodale Institute’s website.

In addition, an article was published in the July 2017 issue of BioCycle.