spaceSpace and Physics

Astronaut Performs First-Ever Plant Transplant In Space


Katy Evans

Katy is Managing Editor at IFLScience where she oversees editorial content from News articles to Features, and even occasionally writes some.

Managing Editor

pak choi on board the ISS

This pak choi has the honor of being the first plant transplant carried out on the ISS. A tiny but important pioneer. Image credit: NASA

There are many living organisms aboard the International Space Station (ISS), from astronauts and cosmonauts to plants, bacteria, and fungi. Ensuring all of them are well and healthy is the humans’ responsibility, so when astronaut Mike Hopkins noted an ailing inhabitant, he did the ISS equivalent of rushing it into surgery and performed a life-saving transplant. The patient? A pak choi.

On Earth, plant transplants are risky enough when plants are in a delicate state. In space, it had never been attempted before – and to the surprise and delight of both Hopkins and the NASA scientists on Earth working on the agency’s Vegetable Production System (Veggie), it worked.


According to NASA, the transplant recipients are doing well. “The transplants – ‘Red Russian’ kale and ‘Extra Dwarf’ pak choi – are surviving and growing along with the donor kale and pak choi,” it said in a statement.  

In fact, the transplanted plants likely wouldn't have survived on Earth. Now, they are growing better than they would have on our home planet thanks to an unusual ingredient up there: microgravity. 

Before you get concerned that this is how horror movies start, where humans have gotten involved in something they shouldn't have and the corridors of the space station are soon going to echo to the ringing demands of "Feed me, Seymour," Hopkins is due to harvest the crop today. The astronauts will eat part of it, while the rest are sent back to Earth to be studied. 

While the human inhabitants get plenty of nutritious packaged food on the ISS, vitamins in a packaged diet can break down, their nutrition decreasing the longer they are in storage. The idea of being self-sufficient and growing your own veg may be vital for long-term space missions and future settlers on another planet.

first plant trasnplant in space
The pak choi after the successful transplant is already sitting up in bed and receiving visitors. Image credit: NASA 

The Veggie experiment has been on board the ISS since 2018, and has seen lettuces, mustards, and even radishes flourish, growing on little "pillows" that contain clay-based substrate and fertilizer. However, when Hopkins checked in on the veggies in mid-January he noticed some of the Red Romaine and Dragoon lettuce seeds were germinating slowly, far behind the other plants. So slowly, in fact, it looked like they would not catch up by harvest time.

So, with guidance from the Veggie team on Earth, Hopkins carried out the experiment, transplanting extra sprouts from the thriving plants onto the pillows of the struggling plants, and it worked.

“This little accidental transplant success is going to be pretty important; it opens up a lot of areas for future development,” said Matt Romeyn, lead scientist on NASA's VEG-03I project, who was pretty pessimistic about the plants' survival in space.

“We’re used to microgravity working against us in the fluids/physics department, making growing plants in space very difficult. So to have an exception like this, where microgravity appears to be helpful and the plants are growing better than on Earth … that’s astonishing.”


So how does microgravity help the plants? “Fluids behave very differently in space than on the ground. The behavior of fluids – in this circumstance – seems to have helped the plants,” Veggie program plant scientist Gioia Massa said

Now we just have to wait for the samples to make it back to Earth to see if we've got a Day of the Triffids-esque scenario on our hands. 

spaceSpace and Physics