Who Grows Plants in Space, and Why?

The first mention of the idea of growing plants in space appeared in Edward Hale’s science fiction story, “The Brick Moon.” Nearly a century and a half later, Matt Damon’s character in the film “The Martian” grew potatoes on Mars to survive until his next mission and his return to Earth. Director Ridley Scott effectively portrayed this process realistically, even explaining how such gardening experiments could be possible.

In reality, humanity is still far from large-scale crop cultivation in space. But there is good news: “space gardens” are no longer the purely fantastical idea they seemed in the 19th century. Today, it is already possible to grow plants in space, albeit with difficulty, and such projects largely remain research-focused.

Why would anyone grow plants in space?

In short, the main reason for growing plants in space is the same as in “The Martian”: to provide food for astronauts who will spend many months, or even years, in space. Ahead of the planned missions to the Moon and Mars under the Artemis program, the issue of supplying astronauts with sufficient food, along with essential vitamins and micronutrients, is being raised more and more often. Currently, this problem is being addressed by delivering supplies of freeze-dried and prepackaged meals, as well as tablet-based vitamin supplements, to astronauts. 

Fresh supplies of food are, of course, regularly sent to the ISS, where astronauts spend weeks or even months conducting research. However, this is a very expensive practice: just a few years ago, delivering a kilogram of food to the space station cost between $20,000 and $40,000. Although costs have decreased thanks to reusable launch vehicles, they will still rise in proportion to the distance from Earth during deep-space missions (that is, it will cost less to deliver to the ISS than to the Moon, and less to the Moon than to Mars, etc.). In addition, food partially loses its nutritional value and taste over time, and even favorite dishes can become bland and monotonous. There is also the issue of packaging, which is usually the first thing to break down. Meanwhile, food itself can remain edible for quite a long time–up to 18 months–but even that shelf life may be insufficient in light of the length of some planned missions. Needless to say, spoiled food can endanger astronauts’ health, and getting sick hundreds of thousands of kilometers from home is… far from desirable: astronauts suffering from food poisoning pose a risk to the mission itself, compromising its goals.

The need to feed and nourish astronauts has formed NASA’s main argument in favor of conducting experiments with growing plants in conditions of microgravity, limited space, and without sunlight. To this end, the agency launched the Deep Space Food Challenge to help develop technologies for cultivating plants in space with sufficient nutritional value. The competition was held in several stages, from 2021 to 2024, and among the finalists were projects for developing an artificial photosynthesis system and a system for selecting fire-safe meals from available long-shelf-life ingredients.

Beyond the obvious nutritional value, interest in plants in space is also motivated by other factors as well. For example, they naturally produce oxygen and reduce the concentration of carbon dioxide in the air, meaning they can form part of astronauts’ life-support ecosystem. Finally, tending a space garden has a positive effect on astronauts’ mental health, helping them better cope with isolation far away from home.

What prevents systematic agriculture in space?

The challenges facing any large-scale project to grow plants in space are diverse and differ greatly depending on the distance and duration of the mission. Jenny Mortimer, lead researcher at Australia’s Centre of Excellence in Plants for Space (P4S), explains that “it all depends on where you want to grow them [plants] — in low Earth orbit, on the surface of a planet, or inside a spacecraft, since each of these options comes with its own difficulties, though there are also factors common to all.”

The primary, and most obvious, obstacle, scientists say, is the harsh conditions of space, which include a near-total vacuum, extremely high or low temperatures, and destructive solar radiation. In addition, plants on Earth develop under the influence of gravity, which affects the biogeochemical processes inside plant cells and how the root system absorbs nutrients for growth. In weightlessness, plants lose their ability to orient themselves in space, and the natural instinct that makes roots grow downward and stems upward disappears.

High doses of radiation also play a role. NASA has confirmed that plants exposed to radiation undergo DNA-level changes. Scientists still need to determine whether these changes are passed on to future generations. Meanwhile, resources required for growth in space are limited, though they can be partially supplemented with soilless farming methods (hydroponics and aeroponics) and LED lamps that match the efficiency of sunlight. Finally, resources such as water, light, and carbon dioxide must be supplied in strictly controlled amounts. Someone or something, moreover, has to constantly monitor all of this. This can mean either automated systems, which are already being used for this purpose, or astronauts themselves… and they are already rather busy.

Early Experiments

The first seeds traveled into space in 1946, carried to an altitude of 134 km aboard an American V-2 rocket. However, scientists were unable to make them germinate back on Earth. Success was later achieved with the use of corn seeds, which were sent into low Earth orbit four weeks after the first batch. Later experiments included rye and cotton. At the time, researchers from Harvard University and the Naval Research Laboratory were investigating how radiation affects living organisms. 1947 also saw the first animals (or rather, insects) sent into space–in this case, fruit flies, which, incredibly, share many genetic traits with humans.

Almost 20 years later, in 1966, the Cosmos-110 spacecraft carried two dogs, Veterok and Ugolyok, into low Earth orbit, along with a new batch of pre-moistened seeds. Some of those seeds sprouted and later produced harvests of lettuce, cabbage, and beans back on Earth.

Such experiments did not involve growing plants directly in space, but they did help scientists understand how space conditions can affect seeds, their germination, and eventual yields. Another notable experiment was the growing of so-called “moon trees,” which were planted on Earth twice: after the Apollo 14 mission in 1971 and Artemis I in 2022. The first initiative came from Edward P. Cliff, head of the U.S. Forest Service, who asked astronauts to take a canister with 500 seeds from five tree species with them into space. NASA later decided to repeat the experiment and sent about 2,000 seeds aboard the Orion spacecraft launched by the Space Launch System rocket. These seeds, representing the flora of 48 U.S. states, spent six weeks in space and were then distributed for planting to government and educational institutions through a competitive program. As for the seeds from the first batch, they were also planted in other countries. For example, in the United Kingdom, plaques can be found next to some of these “moon trees.”

After the “moon trees,” other studies followed. In 1982, several varieties of cress (Arabidopsis) were grown aboard the Soviet Salyut-7 station, making it the first plant to flower and produce seeds in space. Even earlier, rice was cultivated on Skylab, where astronauts studied the influence of gravity and light on sprouts.

European scientists also experimented with seeds in space: in 2018, the German Aerospace Center launched the EuCROPIS satellite into low Earth orbit to model and test the operation of two greenhouses. Tomatoes were grown under gravity conditions closely resembling those on the surface of the Moon. However, the experiment did not yield the expected results: the greenhouses functioned normally, but the irrigation system did not.

The ISS as the main platform for space agriculture 

Experiments with sending and germinating seeds in space showed positive results, so research was moved directly into space. The main site for this work was the International Space Station. Renewed interest in space agriculture in recent years has been fueled by plans for future deep space missions, during which humans will hopefully begin growing plants on the Moon and, eventually, on Mars.

In 2010, the first attempts to grow cabbage and several other types of plants on the ISS proved successful. For example, in 2012, astronaut Donald Pettit managed to capture on camera not only the germination but also the flowering of a sunflower.

In 2014, the “Veggie” space garden project was launched on the ISS, and it continues to this day. The project helps NASA study plant growth in microgravity and diversify the diets of those working on the space station. In August 2015, American astronauts for the first time ate a harvest of red romaine lettuce grown on the station. A year later, they succeeded in growing zinnia, a popular garden plant considered partially edible, on the ISS.

Many Veggie experiments involved Mike Hopkins, often called the “space gardener.” In his view, growing plants in space helps astronauts become more self-sufficient and provides an additional source of necessary vitamins while on board the ISS. As part of the VEG-03I experiment, Hopkins transplanted plants, and their root systems successfully adapted to the new environment. In the VEG-03J experiment, he used a seed film developed at the Kennedy Space Center in Florida that enabled a new method of planting lettuce directly in orbit. Previously, plants had to be placed in prepared soil before being sent to the ISS. VEG-03K and VEG-03L, meanwhile, included growing Amara mustard and Extra Dwarf bok choy, respectively, on the space station.

“Plants grown in space serve as a food source that can improve astronauts’ nutrition, while at the same time, making future crews more self-sufficient,” says Hopkins. “Secondly, these plants connect us with Earth. Their appearance, the feel of touching them, their taste and smell remind us of life on Earth, and this connection is beneficial for our mental health.”

Other studies, Veg-04A and Veg-04B, helped determine how lighting and fertilizers affect plant growth in space. Scientists discovered that different light spectra, red and blue, partly determine the nutritional value of leafy crops. In the joint NASA–ESA Plant Signaling project, the effects of gravity on germinated seeds were studied in detail. With the participation of the Japan Aerospace Exploration Agency (JAXA), researchers also confirmed the role of auxins, or plant hormones, in root system growth under space conditions.

In 2017, another plant-growing system was added to the ISS alongside Veggie: the Advanced Plant Habitat (APH), a highly automated setup requiring minimal human involvement. APH is a closed life-support system with a chamber for various experiments that make it possible to analyze what determines the taste of plants grown in space and how the space environment affects their genetic structure.

What’s next?

The study of auxins, to which Japanese scientists contributed, will help build more efficient space-based systems for growing plants. Meanwhile, the results of the Plant Signaling project will make it possible to create plant varieties that are more resistant to harsh conditions through genetic modification. At the University of Adelaide in Australia, the P4S research group is working on developing nutritious plants that produce zero waste, such as duckweed, in order to tailor cultivation methods to the needs of astronauts hundreds of thousands of kilometers from Earth. Currently, scientists from P4S and NASA are jointly developing a platform that will allow astronauts to grow their own food during long-duration deep space missions.

Scientists from the Lunar Effects on Agricultural Flora (LEAF) project are also studying the factors that most strongly influence plant growth in space. The project will cover key scenarios for cultivating plants on the Moon and beyond and is being carried out in partnership with NASA under the leadership of Space Lab Technologies. According to Space Lab, “once seedlings are delivered back to Earth by the Artemis III mission, the research team will use advanced systems biology tools to study physiological responses at the molecular level.”

As part of the LEAF project, a 40-kilogram chamber with a volume of 35 liters will be transferred from the landing module to the lunar surface. It will be powered by two solar panels, and water will be supplied using a piston system, enabling plant cultivation in deep space via hydroponics. Some plants will be returned to Earth just a few days after the space journey, but the majority will remain on the Moon for further study. The plant species involved have previously been grown on the ISS: Arabidopsis, duckweed (Wolffia), and a variety of turnip (Brassica rapa). Duckweed is of particular interest because it is highly nutritious, produces very little waste, and grows rapidly: its biomass doubles roughly every two days.

Fungi, which are closely associated with plants in nature, could also become a part of future space stations — in a literal sense. Using mycelium grown on the Moon or Mars, astronauts could construct strong, safe, and environmentally friendly structures on-site. NASA is exploring this approach through the Mycotecture Off Planet project. In the future, astronauts could even carry a compact structure made of lightweight material containing fungal spores. Once water is added, the structure would expand and transform into a fully functional habitat for humans.

Another intriguing possibility involves cultivating space gardens and farms for medical purposes. This would go beyond providing psychological benefits for astronauts in long-term isolation and would include serving as a source of pharmaceutical compounds. Currently, NASA’s Food and Pharmaceutical Synthesis Division (FPSD) is experimentally synthesizing medicines from plants and microorganisms. One example is spirulina, which could be used as a basis for producing aspirin. There is also the possibility of sending genetically modified seeds into space, allowing astronauts to grow plants for medical use. This would enable crews on the Moon or Mars to respond relatively quickly to health threats. Obviously, though, the proper conditions for agriculture would first need to be established, and astronauts would need to be properly trained to produce and purify medicines from these plants.