Low-cost Farm-made Indigenous Soil Microbial Inoculant: Yield Impact on High Tunnel Grown Tomatoes

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2022: $7,704.00
Projected End Date: 01/15/2024
Grant Recipient: Mellowfields Farm
Region: North Central
State: Kansas
Project Coordinator:
Kevin Prather
Mellowfields Farm


  • Vegetables: tomatoes


  • Animal Production: inoculants
  • Crop Production: biological inoculants, high tunnels or hoop houses
  • Soil Management: soil analysis

    Proposal summary:

    Improving soil health in high tunnels is an on-going struggle for many. The “desert effect” from lack of rainfall in tunnels, combined with frequent tillage, can lead to the destruction of microbial diversity. Many methods of replenishing these beneficial bacteria and fungi can be expensive (purchased inoculants),  tie up valuable farm real estate (covercropping), or be laborious (vermicomposting, etc.). By producing our own farm-made microbial inoculant, we hope to increase the soil’s microbial community (ecologically sound), increase yields & decrease costs (economically viable), and save the farmers’ time through this simple system (socially responsible).

    Four ingredients: potatoes, leaf mold, salt,  & water. ‘Wild caught’ soil microbes from leaf mold proliferate by feeding on a dextrose nutrient media (potato water). In this system, most ingredients would be available on-farm (potatoes & leaf mold). The only ingredient to purchase-in would be salt, which is easily accessible. If potatoes aren’t grown on-farm, they are cheaply accessible from any supermarket.

    Project objectives from proposal:

    • Develop a simple, affordable system for making and applying farm-made microbial inoculants within high tunnel-grown tomato production (Year 1)
    • Determine the effect of farm-made microbial inoculant on overall yield of tomatoes through multiple successions over the course of a full season (Year 2)
    • Share findings through field days and social media (Year 2)


    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.