A practical overview for farmers, advisers, and researchers

Plasma Activated Water (PAW) is created when atmospheric plasma interacts with water, producing a solution rich in reactive oxygen and nitrogen species (RONS) such as nitrates, nitrites, hydrogen peroxide, and ozone. These compounds give PAW antimicrobial properties and can act as a mild nitrogen source, making PAW a promising chemical-free input for agriculture. PAW is emerging as a potential alternative to conventional fertilisers, seed treatments, and pesticides, and can be produced on‑farm using only air, water, and electricity. [plasmatrea...ment.co.uk]

Interest in PAW is growing in the UK and internationally as farmers look for sustainable tools that support plant health, reduce reliance on imported fertiliser, and improve resilience. Research indicates PAW can enhance seed germination, root growth, disease suppression, and nutrient availability. [ukagritechcentre.com] firewaterag.uk

How PAW Works

Cold atmospheric plasma energises air, creating a reactive mix of ions, electrons, and radicals. When this interacts with water, it forms long‑lived species such as nitrate, nitrite, hydrogen peroxide, and short-lived radicals. The resulting PAW typically shows:

  • Lower pH
  • Higher conductivity
  • Higher oxidation‑reduction potential (ORP)
    These chemical changes are responsible for PAW’s agronomic and antimicrobial effects. [plasmatrea...ment.co.uk]

Uses in Agriculture

1. Seed Treatment and Germination

PAW can stimulate quicker and more uniform germination by:

  • Helping break dormancy
  • Promoting early root development
  • Reducing seed-borne pathogen loads
    Studies show enhanced germination and root growth following PAW treatment.
    Research on tomatoes found PAW-treated plants increased shoot length by 1.5×, leaf count by 4×, and chlorophyll content more than doubled vs control plants. [ukagritechcentre.com] [researchgate.net]

2. Crop Nutrition and Nitrogen Supply

PAW contains nitrate and nitrite, offering a renewable, electricity-driven alternative to synthetic nitrogen fertiliser. It can be produced on‑farm using renewable energy, reducing reliance on fossil fuel‑derived fertilisers and improving nutrient circularity.
This supports sustainable nutrient management and may reduce emissions associated with fertiliser production and transport. [mdpi.com]

3. Plant Growth and Stress Resilience

PAW has been demonstrated to:

  • Increase biomass accumulation
  • Improve chlorophyll content
  • Enhance tolerance to environmental stresses
    Such effects likely stem from mild oxidative stimulation and improved nitrogen availability. [mdpi.com]

4. Disease Control and Hygiene

Because PAW contains reactive species that kill microbes, it can reduce:

  • Fungal and bacterial load on seeds
  • Pathogens on leaf surfaces
  • Contamination in wash water
    This makes PAW a potential chemical‑free sanitation option in horticultural and food-handling environments. [plasmatrea...ment.co.uk]

5. Soil and Environmental Benefits

PAW use may support:

  • Reduced chemical fertiliser inputs
  • Improved soil microbial balance
  • Lower risk of nutrient leaching
    Commercial PAW systems emphasise soil quality improvements and long-term fertility benefits. [pawersolutions.com]

On-Farm Production and Practicality

PAW can be generated on the farm using compact plasma units powered by standard electricity. These systems:

  • Require only water, air, and electricity
  • Incur very low operating costs
  • Can scale from small horticultural setups to large arable farms
    Some UK trials and innovation programmes are exploring PAW integrated with slurry treatment and on‑farm nitrogen capture technologies. [ukagritechcentre.com]

Limitations and Considerations

  • Technology is still emerging; on‑farm agronomic guidelines are not yet standardised.
  • PAW’s effectiveness depends on concentration, storage time, and application method.
  • Not a direct replacement for full nitrogen fertiliser programmes, but may complement them in integrated systems.
  • More field-scale trials are needed across different soils, crops, and climates.

Suggested Links for a FarmPEP Topic Page

Background & Technical Information

Research Articles

Commercial Systems & Innovation

 

This topic summary was written with the help of Microsoft Copilot.

Related Organisations

Content below is from across the PEP community and is not necessarily endorsed by Stewards or by PEP

Connected Content

Nitrogen

Nitrogen is required annually by most crops (except pulses) to achieve yield and quality. Judging how much N to apply is a key part of nutrient management.

NCSPulse PEP
Regenerative Agriculture

Regenerative farming looks to optimise the use of the ecological system and environment, in order to benefit from the natural ecosystem services that they provide.

Nitrogen Use Efficiency (NUE)

Nitrogen Use Efficiency is a widely used term increasingly discussed across industry and between farmers. However it can mean different things to different people, and is best defined with care.

NCSPulse PEP
Sustainable Agriculture

This Topic doesn't yet have a Stewarded summary, but connected groups, content and organisations show below. Click the 'Ask to Join' button if you would like to be a Steward for this Topic and provide a summary of current knowledge and recommend useful resources, organisations, networks and projects. "Like" this Topic if you would like to see it prioritised for providing a wikipedia style summary.

Enhanced Efficiency Fertilisers

A range of products are commercially available that claim to enable more efficient nutrient uptake, allowing less nutrient to be applied as fertiliser.

Alternative Fertiliser Technologies

Fertilisers, especially nitrogen, give some of the biggest environmental impacts of any inputs, from both their manufacture and their application.  A range of innovative approaches are being developed to reduce the energy costs, greenhouse gas emmissions and waste associated with the production of fertilisers.

FireWater - On-farm Nitrogen plasma electrocatalysis ADOPT project

This Defra ADOPT project is testing an exciting new technology from the United States that can allow farmers to produce nitrogen on-farm with a low-cost electro-catalysis plasma process.   

FireWaterUK Agri Ltd

Firewater is a revolutionary technology enabling production of nitrogen fertiliser on-farm at low cost through plasma electro-catalysis. Developed in the US, we've now brought the technology to the UK through an Innovate UK supported Defra ADOPT grant.

About text formats
Write whatever you want here - this is the main section. You can add links, add pictures and embed videos. To paste text from elsewhere use CTRL+Shift+V to paste without formatting. Add videos by selecting 'Full HTML' below, copying the 'embed html' from the source page (eg Youtube), clicking 'Source' above and pasting where you want the video to appear.
You can upload an image here. It can be jpg, jpeg, gif or png format.
Upload requirements
File

You can upload a file here, such as a pdf report, or MS Office documents, Excel spreadsheet or Powerpoint Slides.

Upload requirements
Authors Order
Add Authors here - you can only add them if they already exist on PEP. Just start writing their name then select to add it. To add multiple authors click the 'Add another item' button below.

Please ensure that you have proof-read your content. Pages will go to an admin for approval before going live.

Configure the meta tags below.

Use tokens to avoid redundant meta data and search engine penalization. For example, a 'keyword' value of "example" will be shown on all content using this configuration, whereas using the [node:field_keywords] automatically inserts the "keywords" values from the current entity (node, term, etc).

Browse available tokens.
Basic tags

Simple meta tags.

The text to display in the title bar of a visitor's web browser when they view this page. This meta tag may also be used as the title of the page when a visitor bookmarks or favorites this page, or as the page title in a search engine result. It is common to append '[site:name]' to the end of this, so the site's name is automatically added. It is recommended that the title is no greater than 55 - 65 characters long, including spaces.
A brief and concise summary of the page's content, preferably 150 characters or less. Where as the description meta tag may be used by search engines to display a snippet about the page in search results, the abstract tag may be used to archive a summary about the page. This meta tag is no longer supported by major search engines.
Advanced

Meta tags that might not be needed by many sites.

Geo-spatial information in 'latitude; longitude' format, e.g. '50.167958; -97.133185'; see Wikipedia for details.
Geo-spatial information in 'latitude, longitude' format, e.g. '50.167958, -97.133185'; see Wikipedia for details.
Robots
A comma-separated list of keywords about the page. This meta tag is used as an indicator in Google News.
Highlight standout journalism on the web, especially for breaking news; used as an indicator in Google News. Warning: Don't abuse it, to be used a maximum of 7 times per calendar week!
This meta tag communicates with Google. There are currently two directives supported: 'nositelinkssearchbox' to not to show the sitelinks search box, and 'notranslate' to ask Google not to offer a translation of the page. Both options may be added, just separate them with a comma. See meta tags that Google understands for further details.
Used to rate content for audience appropriateness. This tag has little known influence on search engine rankings, but can be used by browsers, browser extensions, and apps. The most common options are general, mature, restricted, 14 years, safe for kids. If you follow the RTA Documentation you should enter RTA-5042-1996-1400-1577-RTA
Indicate to search engines and other page scrapers whether or not links should be followed. See the W3C specifications for further details.
Sets a cookie on the visitor's browser. Can be in either NAME=VALUE format, or a more verbose format including the path and expiration date; see the link for full details on the syntax.
Tell search engines when to index the page again. Very few search engines support this tag, it is more useful to use an XML Sitemap file.
Control when the browser's internal cache of the current page should expire. The date must to be an RFC-1123-compliant date string that is represented in Greenwich Mean Time (GMT), e.g. 'Thu, 01 Sep 2016 00:12:56 GMT'. Set to '0' to stop the page being cached entirely.
Open Graph

The Open Graph meta tags are used to control how Facebook, Pinterest, LinkedIn and other social networking sites interpret the site's content.

The Facebook Sharing Debugger lets you preview how your content will look when it's shared to Facebook and debug any issues with your Open Graph tags.

The URL of an image which should represent the content. The image must be at least 200 x 200 pixels in size; 600 x 316 pixels is a recommended minimum size, and for best results use an image least 1200 x 630 pixels in size. Supports PNG, JPEG and GIF formats. Should not be used if og:image:url is used. Note: if multiple images are added many services (e.g. Facebook) will default to the largest image, not specifically the first one. Multiple values may be used, separated by a comma. Note: Tokens that return multiple values will be handled automatically. This will be able to extract the URL from an image field if the field is configured properly.
The URL of an video which should represent the content. For best results use a source that is at least 1200 x 630 pixels in size, but at least 600 x 316 pixels is a recommended minimum. Object types supported include video.episode, video.movie, video.other, and video.tv_show. Multiple values may be used, separated by a comma. Note: Tokens that return multiple values will be handled automatically.
A alternative version of og:image and has exactly the same requirements; only one needs to be used. Multiple values may be used, separated by a comma. Note: Tokens that return multiple values will be handled automatically. This will be able to extract the URL from an image field if the field is configured properly.
The secure URL (HTTPS) of an image which should represent the content. The image must be at least 200 x 200 pixels in size; 600 x 316 pixels is a recommended minimum size, and for best results use an image least 1200 x 630 pixels in size. Supports PNG, JPEG and GIF formats. Multiple values may be used, separated by a comma. Note: Tokens that return multiple values will be handled automatically. This will be able to extract the URL from an image field if the field is configured properly. Any URLs which start with "http://" will be converted to "https://".
The type of image referenced above. Should be either 'image/gif' for a GIF image, 'image/jpeg' for a JPG/JPEG image, or 'image/png' for a PNG image. Note: there should be one value for each image, and having more than there are images may cause problems.
The date this content was last modified, with an optional time value. Needs to be in ISO 8601 format. Can be the same as the 'Article modification date' tag.
Links an article to an author's Facebook profile, should be either URLs to the author's profile page or their Facebook profile IDs. Multiple values may be used, separated by a comma. Note: Tokens that return multiple values will be handled automatically.
The date this content was published on, with an optional time value. Needs to be in ISO 8601 format.
The date this content was last modified, with an optional time value. Needs to be in ISO 8601 format.
The date this content will expire, with an optional time value. Needs to be in ISO 8601 format.
Twitter Cards

A set of meta tags specially for controlling the summaries displayed when content is shared on Twitter.

Notes:
  • no other fields are required for a Summary card
  • Photo card requires the 'image' field
  • Media player card requires the 'title', 'description', 'media player URL', 'media player width', 'media player height' and 'image' fields,
  • Summary Card with Large Image card requires the 'Summary' field and the 'image' field,
  • Gallery Card requires all the 'Gallery Image' fields,
  • App Card requires the 'iPhone app ID' field, the 'iPad app ID' field and the 'Google Play app ID' field,
  • Product Card requires the 'description' field, the 'image' field, the 'Label 1' field, the 'Data 1' field, the 'Label 2' field and the 'Data 2' field.
A description that concisely summarizes the content of the page, as appropriate for presentation within a Tweet. Do not re-use the title text as the description, or use this field to describe the general services provided by the website. The string will be truncated, by Twitter, at the word to 200 characters.
By default Twitter tracks visitors when a tweet is embedded on a page using the official APIs. Setting this to 'on' will stop Twitter from tracking visitors.
The URL to a unique image representing the content of the page. Do not use a generic image such as your website logo, author photo, or other image that spans multiple pages. Images larger than 120x120px will be resized and cropped square based on longest dimension. Images smaller than 60x60px will not be shown. If the 'type' is set to Photo then the image must be at least 280x150px. This will be able to extract the URL from an image field if the field is configured properly.
The MIME type for the media contained in the stream URL, as defined by RFC 4337.