I played that stupid flower growing thinjg for like an hour and a half and still didn't get the achievement. My arms were too tired so I took my computer chair and started spinning it in a circle. That was working but I wasn't getting any results as far as flowers growing.
I move the chair only to find that I have a lot less flowers grown than I did before. So I say to heck with it. I more than likely wouldn't have got the 6 player achievement anyway. I did get like 850 calories for that other Kinect stuff from this game today though.