Actinic lights are primarily for aesthetic appeal on aquariums. They are not an efficient source of light for plants, and have virtually no red light, so I would avoid them. The 6500K bulbs are ideal, and the 10000K bulbs should also work pretty well. I would consider these options: 1) Stick with what you have. 2) Use the 10000K VHO's, but not the actinics. 3) Combine the above two options. 4) Use the MH's, provided they are not overly blue bulbs like 20000K's or something. If the plants are still fairly small and you can position them all within six inches or so of the bulbs, then one of the first two options should work. If you need more light, I'd consider one of the last two options.

Yes, noon direct sun is generally taken to be 10,000 foot-candles, and close enough to that anywhere in summer. You will not achieve that with fluorescent lighting and don't need to. Sunlight in the morning and evening is not so intense and what your artificial light provides is like morning sun for a straight 16 hours. It works, trust me :) Are you talking about low power metal halide bulbs like 26W or 50W? They are actually less efficient even than a CFL. Metal Halide lamps don't reach high efficiencies until about 400W or more. Even at their best, modern fluorescent tubes are about equally efficient, so metal halides are really restricted to very large scale applications requiring very high light intensity or very large coverage. Given the "light shade" definition, I think you should aim for 1,000fc to start out, maybe 2,000fc for growing on larger seedlings. That would be about 20W/sq ft going up to as much as 40W/sq ft with CFLs, a little less with larger more efficient fluorescents. Once you have the plants growing it becomes very easy to judge whether you have sufficient light.

Been trying to tell people this for a long time mote, but seems curious that people go Chicken Little on one thing and ignore a far more serious danger. And amazingly, people will recycle pop bottles and tuna cans, but won't recycle light bulbs. I truly wish I could understand this fear of change. Personally I think the life span of the CFL bulb useage as a whole will be short in the grand scheme of things, all things considered, as I believe the LEDs will be soon taking over with even better savings. However, people will still put crosses in their windows and sprinkle salt at their doors at that time too I imagine. Somewhere in the future there's going to be a lot of peoples' estates given the chore of disposing of all these hoarded light bulbs too I suspect! I will say that there are some differences in color temperature on bulbs and certain bulbs won't seem as bright as others. I find this true with streetlights when you compare sodium vapors with mercury vapors. (Oh heavens!!! MERCURY!!! Our towns are now hazardous waste sites as are many warehouses, even stores. What will we do?) The lamp next to my recliner had a 100w bulb and 2-60w bulbs. I'd use a 60 for general lighting and if company were here, all three would be on, and for reading the newspaper or something the idea was the 100w. It got to the point with incandescent, I needed the 100w with a 60 for comfortable reading. I switched to a 23w and two 13w CFLs. For reading now I only use the 23w (100w comparable) so in reality, during those times, I'm using 23 watts instead of 160. And there were times I'd burn the 3rd bulb so even to offset the occasional use of two at once, it's still clear about the savings. I can't understand how anyone would think a $5/mo variance in a $30 bill with rates and general useage would not be noticible! So it's no sense trying to discuss it. Question for you hersraterdave: If you had the same failure rate on a single particular brand of incandescent bulb, let's say a batch of Binford brand had similar failure, would you quit incandescents and start using candles? Or might you consider another brand or source? Or some other cause of the trouble? I'm just curious. :) Seriously though, although I'm not pleased with the dimming on the dimmable bulbs I put in the kitchen, I am pleased that I'm using 75watts instead of 225 watts and getting more light in the process. That's the result I wanted anyway. But to be fair, I wasn't pleased with the flickering of incandescent in the same fixture on the dimmers either. Given the energy use, I don't feel bad about leaving it on for a while since it's still cheaper than the incandescent. It remains to be seen how long these will last, but (knock China-made wood) so far, so good.

Even fluorescent lights with dimming capability often have problems at low settings. The rather expensive dimming ballasts for 4 foot tubes do not go all the way to 'off' using the dimmer. If the current in a fluorescent tube gets to low it will not produce enough UV to excite the phosphors enough to carry over even from cycle to cycle at 120 Hz (the arc in the tube is re-established on each half of the 60 Hz voltage cycle).