How does a space garden grow?
Explore the different experiments growing life on the ISS
There’s a variety of plant-growth experiments currently being conducted on the ISS. These studies are mainly designed to investigate how microgravity affects plant growth and development in order to assess the logistics of plant production during long-term space missions. There are also a couple of side benefits. In return for their hard work, astronauts receive a refreshing boost to their freeze-dried diet and experience the simple pleasures of gardening, which enhances their general happiness and wellbeing.
The Vegetable Production System (Veggie) is perhaps the most well-known growth unit on the ISS. The space garden has featured in many photographs taken on the ISS, showing astronauts proudly presenting the fruits of their labour. “I have been intrigued by the Veggie experiments on the International Space Station and wanted to be a part of learning how to grow plants in space,” says NASA astronaut Mike Hopkins.
The Veggie system is the most ‘hands-on’ plant-growth system on the ISS, and is about the same size as a piece of carry-on luggage. There are currently two Veggie units on the ISS, each capable of growing about six plants. A variety of fresh produce has already been grown using the Veggie system, including lettuce, Chinese cabbage, mizuna mustard, red Russian kale and the infamous zinnia flowers that astronaut Scott Kelly took a shine to. Kelly documented his efforts nursing dying zinnias back to health on the ISS, regularly tweeting plant health updates. To his delight he saved the plants, which subsequently erupted in blooms of vibrant orange.
The Veggie growth system is a relatively simple concept. As we all know, soil is messy at the best of times, let alone in microgravity conditions. So in Veggie, plants are anchored into ‘pillows’ filled with clay-based growth media and fertiliser. Water is precisely injected into the growth pillows. These special pillows also help to ensure the plant roots have access to a healthy balance of air, water and nutrients. Without this set-up, the roots would find themselves either drowning in water or completely engulfed by air, as fluids in space tend to form bubbles. The first crop grown in the Veggie system was red romaine lettuce, planted by astronaut Steve Swanson. It grew for 33 days before being harvested, with some returned to Earth for food-safety tests. The results showed the lettuce was safe to eat, and even suggested it to be cleaner than fresh produce purchased from a supermarket.
Another growth system on the ISS is the Advanced Plant
Habitat (APH). It is similar to Veggie in that it uses light-emitting diodes (LEDs) and clay-based growth media for controlled growth, but unlike Veggie, this system is purely automated. The APH is controlled by a ground team at the Kennedy Space Center, who keep an eye on the plants with cameras and more than 180 sensors. With watering, temperature, light and atmospheric humidity levels all controlled by ground teams, the APH doesn’t require much dayto-day maintenance from the astronauts. The sophisticated APH light system contains a wider variety of LED lights than Veggie, with red, green and blue lights as well as white, far red and infrared to support nighttime imaging. The first experiment carried out in the APH grew Arabidopsis thaliana for about six weeks and dwarf wheat for five weeks in 2018.
On a much smaller scale to Veggie and APH are the Biological Research in Canisters (BRIC). These experiments are carried out in small petri dishes and are designed to look at the effects of space on much smaller organisms such as microbes, mosses and algae. With these experiments, scientists want to investigate whether the space environment negatively affects plant defences. After
Kelly nursed several zinnia plants back to health after a fungal infection killed off the rest, it was suggested that plants in space may struggle to fend off pathogens for themselves. This could be disastrous for long-term space missions that are relying on plant production for food. The latest BRIC-LED experiment – BRICLED-002 – was delivered to the ISS on SpaceX’s 20th commercial resupply mission in March 2020.
“These space-focused farming methods could be applied to alleviate human suffering”
Gil Cauthorn
of North Dakota and Astrobotany International Research Initiative (AIRI) program director.
“These space-focused farming methods could be applied to alleviate human suffering associated with food production while also transitioning towards a more environmentally sustainable agricultural infrastructure”.
Plants don’t just have the ability to keep astronauts well fed, they will be critical in keeping astronauts healthy during long-term missions. Currently, astronauts take multivitamins and enjoy a rich selection of prepackaged meals carefully prepared to cover their dietary needs. However, over time, vitamins in prepackaged form break down. While this is not a serious issue for current space expeditions, which experience regular resupply missions, it will be a problem for future long-duration space travel. Vitamin deficiencies can cause serious health problems – after all, a lack of vitamin C was all it took to plague sailors with scurvy. Luckily for our space-faring travellers, we now understand the value of vitamins, and although prepackaged vitamins are unsuited for future long-term space exploration, fresh produce offers nutrients and vitamins in a long-lasting, easily absorbable form.
Plants are not only important for keeping astronauts in tip-top physical condition, they are also advantageous for their mental health. It turns out that growing a little piece of Earth so far from home can help make living in space feel a little less alien. According to NASA, many astronauts found caring for plants in space a fun and relaxing activity, and many would volunteer their spare time to help with gardening duties.
“These plants are a connection to Earth. The look, feel, taste and smell all remind us of life on Earth, and that connection is good for our mental health,” NASA astronaut Mike Hopkins tells All
About Space. “The space station is a world-class laboratory, but can feel a bit sterile at times. Growing plants on board adds a sense of nature, a sense of home and a sense of life to the space station.”
Plants are therefore critical components of future long-term space travel and the potential colonisation of other worlds. While companies invest a great deal of time and money into building the latest and greatest rocket technology, without effective plant-growth strategies, crewed deepspace exploration missions are impossible. Plants are oxygen makers, water purifiers, air cleaners and food givers. While modern rocket technology may get us into space, it’s plants that will keep us there.