Question:
I'm starting vegetable seeds indoors and confused about fluorescent light bulbs. I have regular cool white 40-watt fluorescent bulbs and also a "plant/aquarium" 40-watt tube that gives off a purple glow. Does it matter?
Answer: Most important is the age of the light bulb. As fluorescent bulbs age, their light emission diminishes. The newer the bulb, the brighter the light. Bulbs sold specifically for seedlings are marginally better but probably not worth the expense. Since you have two types, put one tube of each in your shop light fixture. Keep the bulbs about an inch above the plants, moving it up as they grow.