FYears of careful experimentation and research has helped scientists and astronauts reach great milestones in the field of space gardening. Early experiments have led to the germination of this field aboard the International Space Station (ISS), and will eventually bloom to be able to safely growing plants that astronauts can eat in space, Mars and beyond!
“One of their most compelling discoveries was that certain root-growth strategies, assumed to require gravity, really don’t.”
Charles Darwin hypothesized that roots grow by touching their way across the ground and, gravity pulling down on them. This growing pattern is called “Skewing”. In a 2010 experiment aboard the ISS, it was discovered that roots of plants grow skewed like their Earthly counterparts, leading to the conclusion that gravity isn’t essential in root orientation. Plants will seek out nutrients without using gravity as a necessary cue.
In 2014, Expedition 39 installed the Veggie plant growth system, also known as Veg-01. At the same time, a control chamber was activated by researchers at the Space Station Processing Facility at NASA’s Kenedy Space Center in Florida, to shadow the procedures performed in the ISS.
The Veggie system works by placing one seed in ‘plant pillows’. These are special bags with ‘space dirt’ that controls and releases fertilizer. A plant wick is inserted and a seed is placed inside the oriented so that the roots grow into the bag and the stem emerges up and out of the bag. Blue and Red LED lights are set for photosynthesis and give the plants a sense or directions so the keep growing upward. The walls of the Veggie chamber expand to fit the size of the growing crop.
At the beginning and for many years, experiments were sent to the ISS to grow plants, freeze them and send them back to scientists on Earth to study and determine how growing in microgravity affect the plant’s DNA. Then finally, on August 2015, astronauts ate for the first time a veggie they grew in the Veggie System, they ate leaves of a red romaine lettuce. Most of the lettuce from the experiment was packed and frozen to be sent back to earth for more observations on Earth.
In between growing two sets of red romaine lettuce, scientists at NASA also gave astronauts a set of Zinnias, a flowering plant to grow in the Veggie system. Growing Zinnias is a great model for similar long-term crops like tomatoes. Scientists wanted to see how the Veggie system would run under longer-duration systems where the plants must, not only create leaves but, must flower before they produce their fruit. Growing Zinnias was a challenge as they started showing signs of stress. Astronaut Scott Kelly was able to bring back to health some Zinnias and some, that developed fungus, were sent back to Earth for study. In the end, the reward was beautiful flowering Zinnias. Astronauts took many pictures with them and used them as a centerpiece for their dinner table. Some studies show that tending to a garden can help boosts morale, making people feel better, be more relaxed and optimistic.
2017 – 2018 Research
Most recently, with a new addition to the ISS, larger plants are able to be grown. The Advanced Plant Habitat (APH) “is the largest growth chamber aboard the orbiting laboratory. Roughly the size of a mini-fridge, the habitat is designed to test which growth conditions plants prefer in space and provides specimens a larger root and shoot area. ” The APH system is largely autonomous, managing and regulating the temperature, humidity, oxygen, and carbon dioxide levels are controlled from an Earth-based computer relaying instructions and adjustments, which will be essential for growing different types of plants. “APH is equipped with white, red, blue, green, and far red LEDs and has a wide variety of settings capable of producing light from zero to 1,000 micromoles, a unit of measurement used to describe the intensity of a light source.” More light means scientists are able to broaden the species of plants that can be grown and studied in space!
APH will be able to provide the first studies of space-based agricultural cycles -growing seed to seed, from plants grown in space, and planting their seeds again. “In learning more about the conditions plants prefer, botanists here at home may be able to plan new growth strategies for drought and blighted regions or push for the adoption of large-scale automated growth systems in regions with no naturally-arable soil.”