Night Lights

Question

My orchid area is 15 x 18 feet. This is an atrium with walls on three sides, screened on one side and overhead. There is a green outdoor floodlight on a night time sensor. Could this light cause a blooming problem? —Bettie Oldack
 

Answer

Yes. All photoperiodic plants rely on uninterrupted dark periods as a means of determining season. If the night is interrupted by a light, even relatively low-powered or a brief exposure, it can upset the plant's rhythm, and therefore prevent or delay blooming. This is especially noticeable in plants requiring short days (long nights) to flower, such as those that flower in autumn and winter. —Ned Nash