First flower in space heralds giant leap for zero-gravity gardening

A blooming zinnia follows a successful lettuce harvest at the International Space Station, taking astronauts a step closer to their aim of growing fresh food for a future manned mission to Mars

When there is no "up", which way does a flower grow? Astronauts on the International Space Station (ISS) have answered this and other zero-gravity gardening conundrums by growing the first flower in space.

The orange zinnia looks like a daisy and has a reputation for being one of the easiest flowers to grow on Earth. In space, though, it was a challenge getting it to sprout. The flowers seemed doomed in December after four plants developed mould. But at the weekend, US astronaut Scott Kelly, who has been taking care of them, tweeted a photo of a solitary blooming zinnia with the Earth in the distance behind it, with the hashtag #SpaceFlower and the words: "Yes, there are other life forms in space!"