In the hit movie “The Martian,” the fictional NASA astronaut played by Matt Damon struggles to garden on Mars. As it turns out, he’s got competition from some real extraterrestrial green thumbs.

Since May 2014, the space plant growth system, dubbed “Veggie,” has been experimenting with botany on the International Space Station. At first, the Veggie facility only grew its namesake – vegetables, such as red romaine lettuce. In November, the Veggie team decided to try something a little more difficult: flowering plants.

Growing plants in space presents many challenges, not the least of which is how to grow plants in microgravity. The seeds are delivered in plant “pillows” that simulate soil and fertilizer. The facility provides lighting, nutrient delivery, temperature control and carbon dioxide to facilitate plant growth.

For the first floral crop, the scientists settled on study, bright zinnias.

“The zinnia plant is very different from lettuce,” said Trent Smith, Veggie project manager. “It is more sensitive to environmental parameters and light characteristics. It has a longer growth duration, between 60 and 80 days. Thus, it is a more difficult plant to grow… Allowing it to flower, along with the longer growth duration, makes it a good precursor to a tomato plant.”

As with any garden, there were ups and downs. Towards the end of December, Scott Kelly, one of the astronauts in charge of the Veggie project, tweeted that the plants hadn’t been doing well. The struggling zinnias provided ample opportunity for the Space Station gardeners to learn about the process of growing plants in space. The Earthbound Veggie team worked with Kelly to revive the plants and by the second week of January they were healthy again.

Dr. Gioia Massa, NASA science team lead for Veggie, acknowledged that the flowers have not grown perfectly, but the horticultural learning continues. “We have gained a lot from this,” he said. “We are learning both more about plants and fluids and also how better to operate between ground and station.”

In the coming months, the astronaut gardeners have plans to grow cabbage and more lettuce in the Veggie facility, along with tomatoes and another flowering plant. These experiments are imperative, as plant growth is likely to be an essential component in future deep space travel.

“The farther and longer humans go away from Earth, the greater the need to be able to grow plants for food, atmosphere recycling and psychological benefits,” Dr. Massa said. “I think that plant systems will become important components of any long-duration exploration scenario.”