It may look unnatural, but this is part of a series of experiments aboard the International Space Station that sees astronauts growing lettuce in space.
Codenamed VEGGIE, the hardware see the vegetables take root in planting pillows that provide water and nutrients, while a special rig supplies them with red LED light in the absence of sunlight. The experiments see a a variety of plants being grown, but in this case you're looking at lettuce. In fact, the practice look just likes it did in earlier trials back down here on Earth.
NASA claims the the process of growing plant aboard the International Space Station can be used "for educational outreach, fresh food and even recreation for crew members on long-duration missions." We assume the last point refers to the act of growing itself -- rather than the growing of, erm, recreational plants.