Terrariums are great for beautifying your home and office space, ideal for the busy urbanite professional with not much of a green thumb. The greenery and air purifying qualities that plants bring to the environment make them ideal feng shui cures. Are there good or bad plants for feng shui? In general, as long as the plants are kept healthy, and are placed in good feng shui bagua areas, you can be sure they are good feng shui.  A terrarium is a (mostly) closed environment, and can actually be used to illustrate how an ecosystem works. Inside a terrarium’s walls, many different natural processes may be observed: photosynthesis, respiration, and the water cycle.