surffreak
H.T. Care Bear
Just the shift to a different spectrum alone won't make it flower, but the red side of the spectrum does make it easier for plants to produce flowering hormone, so if an auto endures any stress while under mostly red light, it will likely start flowering earlier than a similar plant under the same conditions but lit by mostly blue light. This simulates the sun's rays at a lower angle of incidence (beginning of fall) which makes the rays pass through more air, which shifts the color to red, just like you would see at sunset.
