I assume you're talking about Averrhoa carambola. It's a tropical native, so give it a fairly warm and humid area in your house, with lots of good light, and quite a bit of space since it will get pretty big... Putting in your greenhouse is probably ideal. It might not ever fruit for you, though, unless you can fudge the daylight/dark time for it using grow lamps. (What you're trying for is 12 hours of sun and 12 hours of dark, which is what the species has adapted to. Without this, it won't fruit.)
They're interesting plants, the little ones that I had closed up their leaves when the sun went down. They're pretty delicate from my experience, don't like full, hot sun but like evenly moist soil. Good luck! Ryan
