When stuck in space for extended periods, pretty much everyone has a plant to tend to keep them sane - if they've ever been up there before, at least. [Unnamed 34] takes care of the rest of the plants - those otherwise uncared for, and those poorly cared for, in the ship's hydroponic gardens.
Of course a ship has more than the hull mushroom gardens. That's for oxygen processing at best, dead irradiated everything at worst. Food - even supplemental fresh food - needs to be in better condition than that.
It's considered a dangerous job, working around all that water.