Greenhouse growers in the UK face a set of familiar challenges: controlling pests and pathogens in a protected environment, ensuring high water and nutrient-use efficiency, maintaining crop quality under variable weather, and meeting increasingly demanding sustainability and regulatory standards. The use of ozone – either as a gas in the air or dissolved in irrigation/recirculation water (“ozonated water”) – is emerging as a highly effective tool to address many of these challenges.
What is Ozone and how is it aApplied?
Ozone (O₃) is a molecule made of three oxygen atoms; it is a strong oxidiser and can break down organic material, kill microorganisms, and revert back to oxygen in water or air when used correctly. In greenhouse systems it typically takes two forms:
- Gaseous ozone: injected into the greenhouse or water-treatment chamber to sanitise air, surfaces or water.
- Ozonated (or aqueous) water: irrigation or recirculation water treated with dissolved ozone – thereby delivering both sanitation benefits and higher dissolved-oxygen into the root zone. For example, one hydroponic white paper noted that aqueous ozone increased dissolved-oxygen (DO) markedly, benefiting root growth. (emeraldharvest.co)
The key is proper design, monitoring of ozone concentrations, and ensuring safe operation (since high ozone levels in the air can be harmful to people).
Key advantages for greenhouse cultivation
1. Improved sanitation and pathogen control
In a greenhouse environment, pathogens — in water, on surfaces, in recirculation systems, and in the ambient air or root-zone — pose constant risk. Ozone provides a chemical-free (residue-free) alternative for disinfection.
- Studies have shown ozonated water irrigation significantly reduced plant stress markers and improved enzyme activity in tomato seedlings.
- In hydroponic or recirculating systems, ozone can oxidise organic matter, eliminate biofilm, and reduce microbial loads.
- This means fewer disease outbreaks (for example root-diseases, waterborne pathogens), less downtime, and potentially lower usage of chemical sanitants.
Ozone offers a compelling sanitation option that aligns with organic and integrated pest-management (IPM) strategies.
2. Enhanced water and nutrient use efficiency
With water resources under pressure and rising costs, any technology that helps growers use water more efficiently makes commercial sense.
- Ozonating irrigation/recirculation water can increase dissolved-oxygen levels, which benefits root health. One paper reported that aqueous ozone raised DO substantially and contributed to stronger root systems, faster growth and reduced cropping time.
- Better root health leads to better nutrient uptake efficiency, fewer root disorders, and better crop uniformity — all of which improve yield and reduce waste.
- Additionally, by enabling more reliable reuse of water (thanks to disinfection and organic-load breakdown), ozone supports closed or semi-closed greenhouse systems, which are increasingly attractive in the UK for sustainability and regulation reasons.
3. Quality improvements and stress tolerance
Beyond sanitising and cleaning, ozone treatments can offer direct benefits to crop performance.
- In the tomato-seedling study, ozone-water irrigation significantly improved antioxidant enzymes (SOD, POD, CAT), increased SPAD (a proxy for chlorophyll content) and increased nitrogen content in leave
- Another study showed that dissolved-ozone via fertigation led to higher dry-weight gain and increased phosphorus & potassium content in tomato plants.
- These physiological improvements translate into higher vigour, better resilience to abiotic stress (temperature fluctuations, water stress), improved crop uniformity, and potentially better shelf-life or quality for end-market produce.
For UK growers aiming at premium markets (e.g., high-value salad, niche vegetables, controlled-environment production), these crop-quality improvements can offer a competitive advantage.
4. Reduced chemical use & environmental / regulatory benefits
In an era of increasing regulation on pesticide residues, sanitisers, and water discharge, ozone offers an environmentally friendly route.
- Because ozone decays to oxygen, it leaves no harmful chemical residues (unlike chlorine or some biocides).
- Using ozone helps meet sustainable production credentials, reduces reliance on chemical sanitisation, supports closed-loop water systems, and can lower the risk of discharge of treated water containing chemical residuals.
- For UK growers certified under schemes (e.g., GlobalG.A.P., UK-specific horticulture standards), use of ozone can help demonstrate a proactive sustainability approach.
5. Economic and operational advantages
From a commercial viewpoint, ozone-treated systems can bring tangible operational benefits:
- Fewer disease outbreaks and less loss = improved yield stability and less crop-down time.
- Faster cropping cycles: one hydroponic case study reported reductions of up to two weeks in cropping times after switching to aqueous ozone.
- Lower chemical costs over time (fewer sanitising chemicals, fewer chemical treatments).
- Potential water-cost savings through reuse and lower fresh-make-up demand.
- Better product uniformity, quality and shelf life — which supports higher market prices or reduces discounting.
Given UK energy, water and labour costs, even modest yield or quality improvements can improve margins. Moreover, the ability to claim a sustainability and “clean tech” advantage may help in market positioning (especially for premium and export markets).
Why contact us!
- UK horticultural production is increasingly moving towards high-value, controlled-environment, intensive systems (including vertical farms, hydroponics, recirculating irrigation systems). Such systems are ideal for ozone integration.
- With water scarcity, rising energy and input costs, and tighter regulation (pesticides, water discharge, sustainability claims), ozone offers an enabling technology for future-proofing.
- UK growers competing on quality, uniformity, sustainability or export markets will benefit from technologies that deliver measurable gains — ozone aligns with that trend.
- Consumer and retailer demand for “cleaner”, more sustainably produced food is rising. The use of ozone can support claims of chemical-reduced sanitation, lower water usage, and improved environmental credentials.
Conclusion
For greenhouse growers in the UK, the adoption of ozone (whether as gaseous ozone for space/air treatment or as ozonated water for irrigation/recirculation) offers a compelling set of advantages:
- stronger sanitation and pathogen control,
- improved water and nutrient-use efficiency,
- enhanced crop quality and stress resilience,
- reduced chemical usage and improved sustainability credentials,
- and operational/economic benefits through yield improvement, faster cycles and lower input waste.
While successful implementation demands good system design, monitoring and operational discipline, the pay-off can be significant — especially in the competitive, high-value, sustainably-oriented greenhouse sector of the UK.