Astronaut Scott Kelly posted this picture to Instagram on Sunday, saying “Our plants aren’t looking too good. Would be a problem on Mars. I’m going to have to channel my inner Mark Watney.”
The folks onboard the International Space Station successfully grew, harvested, and ate their own lettuce this year, but the plants in the picture are looking not-so-crisp. What happened?
The space lettuce crop is not in jeopardy. The dying plants in the photo are Profusion zinnias (Zinnia hybrida), a type of flower that you might find in your neighbor’s garden. They’re generally grown for their beauty rather than as food, but they are technically edible.
NASA public affairs officer Dan Huot tells Popular Science that the plants are withering because they’re nearing the end of their natural lifespan of about 60 days.
This particular crop got a lot done during their ephemeral time in this world, though. They are the first flowering plants on the space station, and the astronauts are growing these plants in preparation for growing tomato plants in 2017.
Zinnias take a bit more work to cultivate than lettuce, and they live for about twice as long.
Huot writes in an email:
Tomato plants will be a bigger challenge yet, because they need to grow for about 90 days before bearing their juicy fruits, and then live for an additional 30 days after that. The astronauts will have to pollinate the plants’ flowers themselves, since there are no bees in space.
This post was updated on 12/28/2015 at 12:05 pm EST to include the species name of the zinnia plants.