Beyond earthly soil: The science of China’s space tomatoes

Imagine floating thousands of kilometres above the Earth, feeling a little homesick, and then suddenly spotting a tiny, bright red cherry tomato growing right in front of you. That is exactly what is happening right now on China's Tiangong space station. It is one of the most exciting things happening in space right now.

China's Tiangong station has been up there for about five years. It is shaped like the English letter "T" and is smaller than the famous International Space Station (ISS), which is a joint project of the United States, Russia, Europe, Japan, and Canada. But smaller does not mean less important. Tiangong has two full science laboratories, can hold up to six astronauts (China calls them taikonauts, which simply means "space sailors" in Chinese), and is doing some truly remarkable work.

Interestingly, the taikonauts on board have successfully grown and harvested real, actual cherry tomatoes inside the space station. Earlier videos shared by the crew show small plants inside a box-shaped system, filled with beautiful yellow and red cherry tomatoes. The roots of the plants are visible through tiny windows, being sprayed continuously with a fine mist of nutrients. A special LED light, designed to copy natural sunlight, helps the plants grow healthy and strong.

But how do you even grow a plant in space? There is no soil up there, no rain, no sunshine coming through a window.

“This is where a smart farming method called aeroponics comes in. In simple words, aeroponics means growing plants in air. Instead of putting the roots in soil or water, the roots are left hanging in the air and sprayed regularly with a fine mist that contains all the nutrients the plant needs, like a tiny spa treatment for roots. This uses far less water than normal farming and even less than hydroponics, which is growing plants in water without soil,” explained space analyst Girish Linganna.

Tomatoes are just the beginning. According to global media reports, the crew is now planning to grow wheat, carrots, and even medicinal plants, the kind used in medicines, to understand just how powerful this space farming system can be for long future missions.

So why does this matter so much? “Think about a future mission to Mars. It would take about seven to nine months just to get there. You cannot carry enough food for the entire journey. But if astronauts can grow their own food while travelling, they become self-sufficient. They do not need to depend on Earth for every meal. That changes everything about how far humans can travel in space,” remarked Linganna.

And it is not just about food. NASA itself noted in 2023 that gardening in space gives astronauts a huge mental boost. Being in space for months can feel lonely and stressful. Tending to a plant, watching it grow, and eating something fresh gives a feeling of home, of life, of calm. It is good for the mind as much as the stomach.

Have other astronauts tried this before? Yes, very much. NASA astronauts on the ISS have been growing tomatoes and other plants for many years as part of their research. They have successfully grown lettuce, radishes, and peppers, too. In fact, NASA made a big announcement saying the first tomatoes successfully grown in space were on the ISS.

So globally, both China and the US are now seriously racing to master space farming, each learning from the other's experiments, even if they do not always work together directly. Russia, part of the ISS program, has also done plant experiments on board. The European Space Agency has run projects studying how seeds behave in zero gravity. The world's space agencies all agree on one thing: if humans ever want to live beyond Earth, they must learn to grow their own food up there. China's little cherry tomatoes are a delicious step in that direction.