Enhancing Phytonutrient Content, Yield and Quality of Vegetables with Compost Tea in the Tropics

Project Overview

Project Type: Research and Education
Funds awarded in 2007: $162,500.00
Projected End Date: 12/31/2011
Region: Western
State: Hawaii
Principal Investigator:
Dr. Theodore Radovich
University of Hawaii, Manoa

Annual Reports


  • Agronomic: potatoes
  • Vegetables: cabbages


  • Crop Production: nutrient cycling, organic fertilizers, application rate management
  • Education and Training: demonstration, extension, farmer to farmer, networking
  • Production Systems: general crop production
  • Soil Management: organic matter, soil analysis, nutrient mineralization, soil quality/health

    Proposal abstract:

    Compost teas (defined here as aerated, aqueous extracts of compost) have been demonstrated to improve crop yield and nutritive quality. The potential benefits of compost tea are substantial and are particularly relevant to agricultural production in tropical island environments through their promotion of reduced reliance on off-island inputs, employing natural biological cycles to mitigate year-round pest pressure, environmentally sound waste management to protect watersheds and reefs and improved profitability of small- and mid-sized farms.

    The goal of this project is to improve our understanding of the interactions between compost quality, crop physiology and environmental factors as they relate to plant yield and phyto-nutrient content, particularly under tropical conditions.

    Project objectives from proposal:

    1) Quantify the independent and interactive effects of compost quality and vegetable type under synthetic and organic fertilization on yield and phyto-nutrient content of model root, fruit and leaf vegetables.

    2) Determine, at the whole-farm level, the effect of compost tea applications on yield, phyto-nutrient content and profitability with commercial vegetable operations on three islands in Hawai’i.

    3) Build and enhance the capacity of at least 300 growers to effectively employ compost tea to increase vegetable yield and phyto-nutrient content on their farms.

    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.