The British astronaut has launched a mass experiment to grow the seeds of the salad leaf rocket. They want to compare them with seeds that have not been in space to see if there are any differences.The experiment is being run by the Royal Horticultural Society's campaign for school gardening and the UK Space Agency.
The seeds have been in space for six months and were returned to Earth in March by the former commander of the space station, Scott Kelly.
They have been carefully sorted and packed into packets which are on their way to the 8,500 schools, children's clubs and societies that have signed up for the experiment.