How can we produce enough food to sustain an increasing population? Growing plants without soil could be the answer, explains tulasi krishna With the world’s population nearing 10.0 billion – and global prosperity and the desire for more resource-intensive foods rising steeply too – it’s clear that farming needs to become more productive. One way of meeting future food needs could be vertical farms – growing plants without soil, instead using a nutrient-rich solution to deliver water and minerals to their roots. It’s already being used to increase farming outputs and grow plants in habitats that wouldn’t normally sustain them. Despite sounding like something out of science fiction, it’s nothing new. The Aztecs built floating farms around the island city of Tenochtitlan, and the explorer Marco Polo wrote about seeing floating gardens during his travels through 13th-century China. By the 1930s, Pan American Airways had established a vertical farm on a remote Pacific island to allow its flights to top up with food en route to Asia. Today farmers have to slowly increasing their use of vertical farms, and researchers are looking more closely at how it could solve future food problems. In the future, some of its applications could be out of this world.