How do you grow plants in space? | BBC News

You might have seen space food before, but what about space plants? If NASA wants its astronauts to stay out in space for longer, they'll need to be able to replenish their own food supply. This is nothing new. Astronauts have been growing crops in space for the past 40 years, but there's still an awful lot that scientists are trying to learn about space farming. We have things like radiation that we have to deal with. We also have issues with microgravity. Plants have learned how to detect gravity with their roots and gravity sensing organelles in the plants. And so they know how to use these cues. And without these cues, they have to readapt to this environment. So without gravity, the next cue that they use is light. So how to go up and down, how to orient themselves is based on light now because they don't have gravity. Water behaves very differently in microgravity. It has a high surface tension, so it likes to cling. And when the water clings to the roots, it prevents the roots from breathing. And so the plants can experience things like drought stress. They may just look green to you and me, but plants appear very different when viewed in the infrared and ultraviolet parts of the spectrum. And the scientists here are learning how their appearance changes under different types of stress. Here in the plant processing area, we're giving the plants a stressor. So in this case, we're reducing its watering. Council Station, we know it's difficult to water. And so we can identify through our imaging project using infrared, a visible light, as well as fluorescence, that stress. We take all this data and to make that association, we use machine learning, then we can associate the wavelengths that are most indicative of that stress and include them in a camera that would monitor the plants on station. And this is where the plants live when they get up there, the veggie unit. This is how they grow stuff on the International Space Station. It's a simple LED system as well as a bellows, so it's open to the crew environment. We have two of these and six plants each. So you can imagine we're not making a huge feast, but it's enough for a nice serving of lettuce. It's a bit salad. Yeah. Now, there is a knack to getting these seeds to sprout in space. The way you grow plants on the International Space Station is using this, which is a plant pillow. So this is the wick that sucks the moisture up. You plug your water source into here and you fill the bottom with soil. Then you get your tiny seeds, which stay in these polymer wrappers so they don't zip off and you lose them around the ISS. And you pop it in here and 28 days later, get yourself a lettuce. Aside from the obvious benefits of creating a renewable food source, there are all sorts of other advantages to growing plants in space. Gardening is very therapeutic. It's something that the astronauts would say, hey, you know, let me take care of something green. Make them happy. Plants produce, you know, oxygen and they recycle waste, they recycle water. All this fundamental stuff together will make them a very important organism to take with us. The current goal is to use hydroponic systems, which rely on water-based nutrient solutions instead of soil, which is heavy and expensive to transport. But in 2022, scientists showed that plants can grow in lunar soil. If we want to live on new worlds, we need to use the resources that they provide us instead of taking more from our home planet.