Compost Tea Research

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ANSWERING THE QUESTION:

Does Compost Tea make certain leafy vegetables grow bigger or not?

Effects of Aerated Compost Tea on Swiss Chard, Kale & Lettuce Production in Virginia

A Producer Grant sponsored by Southern SARE (Sustainable Agricultural Research & Education) ending in March 2025.

Links to all Sustainable Agriculture Research and Education Projects on Compost Tea

• Link to Research # 1 on Compost Tea Effect on Leafy Greens

• Link to Research # 2 on Compost Tea Microbiome

Microbial Populations in Compost
vs.
Compost Tea / Extract

Does feeding the microbiology in the soil really make a difference? These results were from teas that were unfed.

This first batch of vermicompost was rained on and not turned due to fear of breaking fungal strands. This resulted in almost anaerobic, too-wet conditions. The tea that was brewed from it was not fed any microbial foods and while resulting in no pathogens, had hardly any beneficial bacteria in it.

Vermicompost Microbiome June 2023 vs.
Compost Tea Microbiome June 2023

The second batch of vermicompost was kept indoors. While resulting in a more robust compost, did not produce a robust tea according to test results. Compost tea sampling 48 hours post-harvest may have skewed true results.

Vermicompost Microbiome November 2023 vs.
Compost Tea Microbiome November 2023

Microbiome Analysis (DNA Test) of Vermicompost & Compost Tea (from Permaculture Gardens) by Dr. Zach Jones

• Vermicompost Report

• Vermi-Compost Tea Report

• Download the Graphs

• Interactive Compost & Vermicompost Krona Graphs

A Krona graph of vermicompost of Nicky Schauder

Microbiome Results

Microbiome Analysis (DNA Test) of Vermicompost & Compost Tea brewed at 12 & 24 hours with different feeds (from Permaculture Gardens) by Dr. Zach Jones

• Vermicompost Report

• Vermi-Compost Tea Report

• Download the Graphs

• Interactive Compost & Vermicompost Krona Graphs with different feeds:

  • Alfalfa Meal

  • Kelp Meal

  • Fish Hydrolysate

  • Humic Acids

  • Molasses

Literature Review of Compost Tea Research

You can read a very broad summary of the studies below here.

I've organized the Compost Tea literature into two categories:

Click on the images above to Zoom in on these two topics.

COMPOST TEA

Studies on Benefits of Compost Tea Application

Read what the literature has to say about five purported benefits of Compost Tea.

1. Plant Growth Promotion

2. Plant Disease Control

3. Plant Resilience in Warming Climates

4. Plant Nutrient Enhancement

5. Enhanced Plant Microbiology

1. Plant Growth Promotion

• ARTICHOKE - Productivity Improving of Artichoke in Organic Farming by Compost and Compost Tea Fertilization.

• CHILI PEPPER - Effect Of Compost Tea and JADAM Microorganism Solution On Growth Of Chili Pepper In PT. Cinquer Agro Nusantara.

• MUSKMELON - Foliar application of microbial-enriched compost tea enhances growth, yield and quality of muskmelon (Cucumis melo L.) cultivated under fertigation system.

• POTATO - A study of selected factors affecting efficacy of compost tea against several fungal pathogens of potato

Annual Plants

Perennial Plants

• OAK - Impacts of Aerated Compost Tea on Containerized Acer saccharum and Quercus macrocarpa Saplings and Soil Properties in Sand, Uncompacted Loam and Compacted Loam Soils - Compost Tea had no significant effect

• BLUEBERRY - Evaluation of Potential Organic Controls of Mummy Berry Disease Affecting Lowbush Blueberry in Maine. - Compost Tea had no significant effect

• SUNCHOKES - Effect of Compost Rates and Topping Treatments on Growth, Yield and Quality of Jerusalem Artichoke Under Sandy Soil Conditions - Compost Tea improved growth of Sunchokes

• SOYBEAN & SWEET CORN - Effects of Aerated Compost Tea on the Growth Promotion of Lettuce, Soybean, and Sweet Corn in Organic Cultivation.

• TOMATO & SWEET POTATO - Effects and relationships of compost type,
  aeration and brewing time on compost tea properties, efficacy against Pythium ultimum, phytotoxicity, and potential as a nutrient amendment for seedling production (tomato and sweet potato).

• TOMATO - Analysis of Bacterial Microbiota of Aerated Compost Teas and Effect on Tomato Growth.

• TOMATO - Combined effects and relationships of compost tea, fertiliser, and Glomus intraradices inoculated- substrate on tomato seedling quality

2. Plant Disease Control

• In vitro and in vivo evaluation of microbial-enriched compost tea on the development of powdery mildew

Powdery Mildew (Fungi: diff Genera)

Grey Mold (Fungi: Botrytis cinerea)

• Compost Tea: Principles and Prospects For Plant Disease Control

Leaf Spot Disease (Fungi: Alternaria alternata)

• Impact of Compost Tea in Controlling Leaf Spot Disease and Soil Microorganisms; Density in Fava Bean (Vicia Faba L)

• Study on the effect of yeast in compost tea efficiency in controlling chocolate leaf spot disease in broad bean (Vicia faba).

• Organic Management: An Alternative to Control Late Blight of Potato and Tomato Caused by Phytophthora infestans

Mummy Berry Disease (Fungi: Monilinia vaccinii-corymbosi)

• Evaluation of Potential Organic Controls of Mummy Berry Disease Affecting Lowbush Blueberry in Maine

Review of Compost Tea & Plant Diesases

• Compost Tea on the Grey Mold (Botrytis cinerea) on Strawberries

3. Plant Resilience in Warming Climates

• Compost Tea 101: What Every Organic Gardener Should Know

Effect & Relationships of Compost Type, Aeration & Brewing Time

• Effects and relationships of compost type,
  aeration and brewing time on compost tea properties, efficacy against Pythium ultimum, phytotoxicity, and potential as a nutrient amendment for seedling production.

Compost Tea 101 (University of Arizona)

4. Nutrient Enhancement

Nutrient Enhancement by Eisenia foetida in compost and compost tea by Ed Stockman (Organic Agrosystems Research)

5. Enhanced Plant Microbiology

Microbiome Analysis (DNA Test) of Vermicompost & Compost Tea (from Living Roots Compost Tea) by Dr. Zach Jones on Vermimicrobiome Website

A Krona graph of vermicompost of Troy Hinke

Report for the analysis of 16S microbiome data by Dr. Laurent Falquet, UniFr
courtesy of Adrian Rubi at www.edapro.ch

A microbiome analysis of bacteria and their populations according to microbial starter (feed) in compost tea www.edapro.ch

Analysis of Bacterial Microbiota of Aerated Compost Teas and Effect on Tomato Growth.

Microbial Starter for the Enhancement of Biological Activity of Compost Tea

Does compost tea really multiply the biology in the original compost it's brewed from? And if so, how much greater are the populations? How much and what do we need to feed the good bugs for them to grow?

Also check out "Table IV: Nutrients and Heavy Metals Composition of Compost Tea Alone and Microbial-Enriched Compost Tea, at Day-3 of Brewing" in this study.

How to Brew Compost Tea

a Compost Tea Podcast Course
courtesy of Troy Hinke of Living Roots Compost

Elaine Ingham's Work on Compost Tea

Dr. Ingham's comprehensive manual on making, applying, and assessing compost tea is now available in its 5th edition. A must for any user of compost tea.

National Organic Standards Board
Compost Tea Task Force Report

What is legally deemed as safe compost tea by the USDA?

Notes on Compost Tea

Soil researcher Steve Diver's comprehensive notes on Compost Teas, literature review until 2002, and slides to his presentation. Really good pictures of the biology and cool compost tea facts in this one!