Fresh greens in space? Recent research has looked into how plants respond to low levels of gravity and a particular hormone which can help plants grow in challenging space conditions. Now, new research has succeeded in growing plants in high-tech planters which use artificial soil made from lava rock.

The goal of the research is to eventually find a way for plants to grow directly in water, with nutrients supplied through the water instead of through soil. Soil is obviously in short supply in space so it’s important to find a way to get nutrients to plants without relying on earth. At the Centre for Interdisciplinary Research in Space (CIRiS), part of the Norwegian University of Science and Technology’s (NTNU) Social Research department, the team has collaborated with researchers from France and Italy to find ways to cultivate plant-based foods in space.

The CIRiS has been testing the high-tech planters made by the NTNU’s technical workshop, which regulate the water, nutrients, gas, and air that plants require. In climate-regulated growth chambers in the Netherlands, the team has been investigating how plants use nitrogen in particular and how the levels of nutrients available affect the amount of water that the plants consume.

“We found that plants can, in a way, ‘smell’ the amount of nutrients available to them,” Silje Wolff, a plant physiologist at CIRiS, explains. “When the nitrogen concentration is very low, the plant will absorb more water and thus more nitrogen until it reaches an optimal level. The plant has a mechanism that turns on when the nitrogen level is adequate. Then it adjusts both nitrogen and water absorption down.”

But another challenge to growing plants in space remains: until the exact mechanisms through which plants adjust to microgravity are understood, the plants still need gravity to grow. The solution for now is to place plants into a centrifuge inside a space station which simulates gravity which the plants sprout and grow.

The research team hopes that their findings will not only be relevant to space expeditions, but could also be used to optimize crop growth here on Earth, especially in places with nutrient-poor soil or within cities without much soil available. “Recycling and precise fertilization are key to achieving more sustainable food production,” Wolff says. “By growing plants directly in water with dissolved nutrients, fertilization and irrigation are much easier to control.”

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