Space garden

SPACE GARDEN Over millions of years of evolution, plants have become perfectly adapted for life on Earth. They are most certainly not adapted to growing in space, yet that is exactly what the plants shown here are doing. As part of an experiment on the International Space Station (ISS), its crew members are growing fresh vegetables in a “space garden” to try to improve their diet.

Plants are sensitive to their surroundings. Their roots grow toward sources of water, and their stems grow toward the light. They also react to gravity, growing up and away from its downward pull. In space, however, these plants are growing in zero gravity, with their roots held down by woven mats. The attraction of the artificial lights above them makes them grow upright, like plants on Earth. They are given water containing vital nutrients, and the ISS crew breathes out the carbon dioxide the plants use to make the sugar they need to grow. In this process, the plants give off oxygen, which improves the air quality within the space station, while the sugar is turned into plant tissue that the crew can eat.