I purchased a new grow light yesterday. When I got it home and hooked it up, I discovered that the light is much more toward the red end of the spectrum than the other lights that I already had. Now I'm wondering if one is better than the other for seed germination. I am germinating peppers, tomatoes and Amaranthus caudatus right now - under the warm spectrum light. I have coleus, basil, Verbena bonariensis and Nicandra seedlings growing under the cool spectrum lights. Am I good with leaving things where they are or should I switch anything around? I have always germinated everything in a south-facing window in the past so I am still trying to figure out the ins and outs of using lights.
This is what is in The New Seed-Starters Handbook by Nancy Bubel
Light. Subjecting the seeds to light-even a dim continuous light or sudden bright photoflash-will sometimes help, especially with lettuce. Germination depends on total amount received. The dimmer the light, the longer the necessary exposure.
Red Light. Exposure of some seeds to red light (660 nanometers) promotes seed germination. Experiments with lettuce bear this out. However, far-red light (730) nanometers) has been found to inhibit seed germination. Practically speaking, this means that seeds that are difficult to germinate will often do better under fluorescent plant lights. Some seeds won't germinate when shaded by leaf cover, probably because the leaves filter out helpful rays while allowing the inhibiting far-red light to reach the seeds."
I garden in Fairbanks Alaska, so I have to start all of my plants inside under lights. I use just plain old inexpensive lights with no problems. If I was planning on keeping plants under lights for their complete life cycle I would consider more expensive grow light bulbs