Farming without soil: new Japanese tech makes growing fruit and vegetables possible in any environment

In a tiny room inside the Mebiol Research and Development Center, a little over an hour outside of Tokyo, baby Cos lettuce leaves are growing in a tray under magenta-coloured lights. On another shelf, a miniature garden of microgreens is blooming across the surface of a salad dish. The seedlings have been cultivated without soil – atop a thin, transparent polymer film.

“Can you see the roots?” asks Hiroshi Yoshioka, Mebiol’s vice-president, lifting the edge of the plant-covered film to reveal a tangle of fine, pale filaments. He pulls the sheet off the plate and holds it in front of him like a leafy green carpet.

The polymer film is the key to a cutting-edge farming method that makes it possible to grow fruits and vegetables on practically any flat exterior. Made of hydrogel – a super absorbent material typically used in household products such as disposable diapers – the film works by soaking up water and nutrients through a multitude of nano-sized pores measuring one millionth of a millimetre in diameter. Plants grow on top of the film, but instead of digging into the ground, the roots spread across the surface of the membrane in wispy, fan-like formations.

Film farming is the brainchild of Yuichi Mori, the chemical physicist who founded Mebiol in 1995.

A spry 75-year-old in a crisp blue-and-white striped shirt and navy blazer, Mori spent the majority of his career developing polymer technologies for the medical industry. However, he had long been fascinated by plant biology and found inspiration in the adaptability of the vegetable kingdom.

“In many ways, plants are more remarkable than humans,” he observes, pointing out that they sustain life on earth by providing a source of food for animals and removing excess CO2 from the air. “I was always thinking of how to maximise the power of plants.”

The idea of applying polymer technology to agriculture that came to him as he was building an artificial kidney nearly 20 years ago. He wondered if the same mechanisms used to construct synthetic blood vessels and membrane filters could be used as a growth medium for vegetables.

“Plants can solve many of society’s problems – from lifestyle diseases to environmental issues,” he explains. “I envisioned a world where we could take plants everywhere.”

He began by growing a small patch of grass on hydrogel film under LED lights. After more than a decade of experimentation, Mori and his colleagues developed a soil-free farming system that could be used to cultivate crops in greenhouses on a large scale.