Botanicult Fiction: Plants in Space, Fact or Fiction?

By Dr. David Galbraith, Head of Science, Royal Botanical Gardens

It might seem like living plants in space is in the realm of science fiction, and as avid readers of this column will appreciate, that situation has been speculated upon for decades. From using plants to keep astronauts alive to rampaging intelligent plants bent on destruction, imagined plants in space have taken many forms.

Reality is gradually catching up with science fiction though. In fact, the first living plant material (seeds) was sent into space in the summer of 1946 aboard early scientific rockets, sent up to test for the effects of radiation. Nearly 50 years ago NASA sent 500 tree seeds into orbit around the moon on Apollo 14. Most of the resulting “Moon Trees” (Douglas fir, Sycamore, Redwood, Sweetgum, and Loblolly pine) were planted at public sites around the USA during 1976, the American Bicentennial Year. Surviving trees continue to thrive, and researchers are now following second-generation Moon Trees (Half-Moon Trees!).

The honour of producing the first flowers and seeds in space went to Rock Cress (Arabidopsis) aboard the Soviet Salyut 7 space station in 1982. This tiny species grew successfully in zero gravity inside a miniature greenhouse within the station. Subsequent space stations (the American Skylab, Soviet Mir, and now the International Space Station) have all flown with space greenhouses on board. The list of plants that have grown successfully in orbit continues to grow. Cucumbers, romaine lettuce, Zinnia ‘Profusion’, cabbage, sunflower, wheat, rice, and tulips, among others, have been grown successfully over the past 20 years. The International Space Station boasts three separate “space greenhouses” now, two copies of the “Veggie” module and a new system, the Advanced Plant Habitat.

There are several goals for all of this. One direct consequence of growing live plants on the ISS is that there is occasionally some fresh food for the station’s crew. The longer-term purpose of growing plants in space is rooted in the realization that all life needs plants, and if we are ever to spend more than a few months in space at a time, we will need to have plants with us for oxygen production, waste recycling, and food production.

Plants have also now been grown on the moon. In January 2019 China’s Chang’e 4 lunar lander touched down on the far side with a miniature growth chamber stocked with cotton, rapeseed, potatoes, and Arabidopsis seeds on board. Of the four species Arabidopsis apparently didn’t germinate. This Lunar Micro Ecosystem will be familiar to anyone who has tried to grow a little garden in a sealed jar or bottle. Included with the plants were yeast and fruit flies to see if they could form a tiny closed ecosystem with the plants. Unfortunately, after a few days on the moon the temperature-regulation system for the experiment failed and the researchers back on Earth shut off the power. I have the feeling this will not be the last time humans grow plants on our planet’s natural satellite.

Despite the successes so far, growing plants in space is far from easy. Plants in orbit don’t have gravity to help with orientation, which can affect the way roots and shoots develop. Nutrient cycles, water and humidity, and even microorganisms need to be understood and controlled to provide the conditions plants need to grow. However, it’s amazing that plants are already in space more than a half-century. One day perhaps we’ll have a botanical garden on the moon.

Botanicult Fiction is an affectionate review of plants in pop culture viewed through the lens of plant nerds and curated for your reading or viewing pleasure during this challenging time of self isolation