When humans go to the Moon or Mars, they’ll probably take plants with them. NASA-supported researchers are learning how greenhouses work on other planets. Confused? Then you’re just like plants in a greenhouse on Mars. No greenhouses exist there yet, of course. But long-term explorers, on Mars, or the moon, will need to grow plants: for food, for recycling, for replenishing the air. And plants aren’t going to understand that off-earth environment at all. It’s not what they evolved for, and it’s not what they’re expecting. But in some ways, it turns out, they’re probably going to like it better! Some parts of it, anyway.