This computer-generated image released by Plantagon shows the design of a vertical greenhouse project. Vertical greenhouses that grow organic fruit and vegetables smack in the middle of crowded cities where land is scarce may soon be a reality, a Swedish company developing the project said Friday.

"A tomato seed is planted on the ground floor on a rotating spiral and when it arrives at the top, 30 days later, you pick the fruit," the vice president of Plantagon, Hans Hassle, told AFP.

In a few decades, 80 percent of the global population will live in cities, increasing the need "to grow fruits and vegetables in an urban environment due to the lack of land," he said.