Chlorella is a type of algea, so it would definitely need to be grown in water. It’s also not very cold hardy – it looks like it can maybe just barely handle a light frost, maybe? – so in order to keep it alive in a temperate climate, it would have to be grown indoors through the winter. It looks like it reproduces asexually, and doesn’t make seeds.
Given the very appealing health benefits of chlorella, I think it would be neat to grow it to eat it. Can this be done in a small scale, maybe in a Rubbermaid bin full of water in a back yard?
I feel intimidated by a water based crop like that because I’m pretty sure I’d manage to contaminate it somehow. But I recall seeing videos of small scale methods for growing it that were being developed to teach in food poor areas of the world.
I wasn’t able to find the videos I watched but it looks like there are loads of people posting tutorials. I’d be curious to see your results if you give it a try.