You can let the leaf color tell you if the light is right. Start out by placing it a foot or so in from the window. The leaf color you are looking for is a nice medium green. What in the world is medium green you might ask. Well if the leaves get a darker green like " forest green" it needs it a bit brighter. If the leaves get yellow green, back off in the light.
The plant will bloom in any case but with optimum light the bloom spikes will carry more flowers, the spikes will be two per bulb.
In bright light the flowers will be paler in color, in too little light they will be fewer and darker and of smaller size.
