Agricultural Soil Steaming Association



Despite over a decade of favorable trial results with soil steam pasteurization on open field applications, there has yet to emerge a commercially available solution for soil steaming in the US.  Agricultural Soil Steaming Association (ASSA) was created to promote the commercialization of this promising technology.


ASSA is a non-profit organization founded by a small group of strawberry nursery growers and researchers with a shared passion for effective alternatives to the chemically-laden status quo in conventional agriculture. We believe that soil steaming represents an answer to many agricultural applications seeking a more organic method of soil disinfestation.  We created ASSA for the sole purpose of bringing large-scale soil steaming equipment from the research phase to commercialization.


We are confident that through our collective efforts, ASSA will be successful in converting soil steam pasteurization from a promising research concept to a commercially available, effectual and economic pest control solution.  ASSA is committed to supporting all aspects and phases of this conversion, including ongoing research, mechanization and commercialization, education, and promotion.

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Why is ASSA needed? 

by Dr. Steve Fennimore, University of California, Davis co-founder and board member of  ASSA.


Support collective action on soil steaming dis-infestation through a commodity board.

Provide  access to program funding that would not otherwise be available. 

Keep focus on realistic technical solutions for the real world of commercial agriculture.

Share expertise, land, labor, shop work, equipment transport, etc.

Image by John Ruddock

Our Mission

ASSA’s mission is to provide for the development and promotion of large-scale soil steaming systems as a viable alternative to chemical fumigation for removing pathogens from soil. 


To this effect, ASSA provides a forum to discuss methods, share ideas and ultimately lead the adoption of large-scale soil steaming systems across the globe.


ASSA mobilizes academic researchers, technical experts, technology suppliers and growers to promote large-scale soil steaming systems which will benefit crop growers across North America and, through them, the general public.


Image by Markus Winkler


Soil Steaming?

Soil steaming is a green farming technique that kills weeds, bacteria, fungi and viruses without leaving any harmful residues. In the US, this technique has been successfully tested as a favorable alternative soil dis-infestation strategy over the banned methyl bromide for strawberry plant nurseries.

It provides a unique and safe solution for organic growers to treat their soil from most soil borne pests, while benefiting from a significant yield increase, with treatment lasting several years.

Image by Tim Mossholder

Our Objectives


Prove the viability of a large-scale commercial soil steaming technology in 2020-2021


Set the groundwork for commercial equipment availability before 2021-22


Establish benefits among all industry constituents for large market adoption in 2022-2023


Promote steam pasteurization technology to public to create a premium end product


Member Benefits

Members of ASSA will benefit from:

  • A commercial impetus focused on long-term sustainability

  • Improved farming practice with increased yield potential and lower environmental impact

  • A lever mechanism using membership financial contributions for grant money

  • A vehicle for grant providers to participate in the market development of new technology

  • Access to cutting-edge technology and first-hand information

Image by Matteo Paganelli

ASSA Services

  • Aggregate technical information

  • Evaluate field test performance

  • Promote new commercial entity integration

  • Provide assistance to growers and other system users

  • Educate market constituents

  • Establish technical recommendations /protocols /standards

  • Facilitate public relations /marketing communication

  • Publish education material 


Field Test Program

Summer 2020-2021


This program, a collaboration between the University of California, Davis and ASSA, will be conducted at multiple locations over a two-year period beginning in August of 2020.  The project is designed to provide the technical foundation required for the commercial demonstrations of 3 different steam applicators, supported by an outreach initiative across constituencies and markets.

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These preliminary tests will verify impressive heat transfer due to their proprietary method that, if confirmed, could be less expensive than MB fumigation. This system has been in development in Norway over the past 25 years.

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JSE commercializes a compact soil steam applicator capable of reaching extremely high temperature with steam injected up to 390 degrees Fahrenheit with depth up to 14 inches.  Their system has been commercially implemented in South Korea.


Noble Plow/US Challenge

This tractor mounted shank sweep applicator will be re-tested with steam only. This simple design concept draws directly from years of fumigant and steam application experience.  The Trical original testing from 2015 has been modified by Sierra-Cascade Nursery, utilizing steam by Staheli Hay Steamer.

Field Trial Calendar

 Click here to view recent trial pictures

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Market Applications

  • Organic products

  • Strawberries

  • Other Berries

  • Cut Flower

  • Lettuce

  • Tomato

  • Greenhouses

  • Parks & Golfs

  • Turf and Nursery

  • Playground

  • Topsoil

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