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Light-altering paint for greenhouses could help lengthen the fruit growing season in less sunny countries

Light-altering paint for greenhouses could help lengthen the fruit growing season in the UK
Credit: University of Bath

Researchers in the UK have developed a new spray coating for greenhouses that optimizes the wavelength of light shining onto the plants, improving their growth and yield. The technology could in the future help extend the growing seasons in less sunny countries like the UK in a more sustainable way. The study is in the journal Advanced Materials Technologies.

Since the growing season in the UK is relatively short due to its climate and latitude, we rely on European imports for most of our fruit and vegetables, grown in vast artificially lit greenhouses, which use huge amounts of electricity.

Now scientists at the Universities of Bath and Cambridge, working with commercial partner Lambda Agri, have developed a spray coating for greenhouses that could help UK farmers to produce more crops in the future using the same or less energy.

Photosynthesis—the process used by plants to capture sunlight and use the energy to convert and water into sugars—is most efficient at the wavelength of red light. Green light is the least efficient which is why plants don't absorb it and so appear green.

Sunlight is a mixture of all the color spectrum so much of the light that shines on plants is not used.

The new spray coats existing greenhouse glass like a varnish; this layer absorbs from sunlight and converts it to red light, increasing the fraction of red light that can be used by the plants which increases the crop yield.

Credit: University of Bath

More sustainable technologies

While other researchers in the U.S. have previously achieved an increase in growth using similar technologies, they use rare earth materials such as indium. This metal is used in phone screens but is very expensive and difficult to recycle.

The Bath/Cambridge collaboration with Lambda Agri have replaced indium with a patent-pending lower cost, more abundant material.

In addition, they can make the materials using a chemical flow reactor, speeding up the manufacture process and making it more easily scalable.

Sweeter fruit

Professor Petra Cameron, from the University of Bath's Institute of Sustainability and Climate Change (ISCC), said, "The way our coating works is similar to when you go to a night club and your gin and tonic drink glows under the UV light—the quinine chemical in the tonic water is absorbing the UV and re-emitting it as visible light.

Light-altering paint for greenhouses could help lengthen the fruit growing season in the UK
The technology could help extend growing seasons and increase food security in the UK. Credit: Martin Bergsma

"Our coating contains molecules that absorb UV light from the sun and converts around 80–90% of it into red light, making photosynthesis more efficient, meaning we can grow more with less light.

"In we've seen a nine percent increase in crop yield when growing basil in treated greenhouses. This means our technology could in the future be used to extend the for produce and use less artificial light to get the same results, saving money and reducing the associated carbon emissions.

"As well as changing the wavelength of the light coming into the greenhouse, the coating also scatters the light, which also increases the yield. There is even some evidence that suggests it improves the taste by raising the sugar content in the fruit."

Professor Dominic Wright from the University of Cambridge, Inorganic and Materials Section in Chemistry, said, "This is a nice application of fundamental molecular science to an important, real-world problem, one that is particularly important in regards to the backdrop of food security and global warming.

"There is a very real prospect of this having a significant impact on the availability and cost of soft fruit and salad vegetables for consumers in the future, especially in northern European countries like the UK where the weather conditions are far from ideal."

Dr. Monica Saavedra, from Lambda Agri, said, "Lambda stands for fighting food poverty, sustainably. Both Cambridge University, where we are currently based, and the University of Bath are strong collaborators and share our vision."

The team has submitted a patent for the technology and hope to make the technology commercially available for growers in a few years.

More information: Rosa Müller et al, Transparent, Sprayable Plastic Films for Luminescent Down‐Shifted‐Assisted Plant Growth, Advanced Materials Technologies (2024).

Journal information: Advanced Materials Technologies

Provided by University of Bath

Citation: Light-altering paint for greenhouses could help lengthen the fruit growing season in less sunny countries (2024, November 20) retrieved 15 August 2025 from /news/2024-11-greenhouses-lengthen-fruit-season-sunny.html
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