6500K is what I use but I have the old T12 bulbs. From what I have read, that is the closest spectrum to the sunlight that peppers use, although they use lower spectrum too. Some people mix 6500K with a 4000K or 5300K bulb.

The T5's should work great....at least as well as T8's or T12's and should be more economical. Some swear by the more expensive type fixtures and bulbs but for growing a couple dozen chili plants, I don't think the cost is worth it and the floro tubes just plain work so that is what I use. I may upgrade to T8's or T5's sometime.
Bruce

Thanks, Bruce. Think I'll stick with two 6500 W bulbs then.

Best regards,
Alex

do the t-5s get hotter than the t-12s? The t-12s i hang right on top of the plants.

John,

I can't say, since I have never used T12 bulbs, but the T5's don't really get all that hot. Maybe someone else with more experience here can give you a better answer.

Alex

i thought i read that they were warmer, but save energy. I have a dorset under 4 t12s thats actually touching the light cause i didn't raise it, and it just started setting peppers again

I don't see how a bulb can be hotter and still save energy. I mean, if its radiating heat then thats a lot of energy being wasted to the air that isn't being turned into light, making it much more inefficient than it should be.

Yes, it is interesting. Because most physics teachers would tell you that the more heat an appliance or motor or whatever gives off, the less efficient it is at what it is designed for (unless it is a heater of course). But I have no experience with T5's so I don't know how hot they get. I do know that very little heat is given off by T12's and I have been told that T5's are more efficient than T12's so I had expected them to give off less heat. However, the fact that they are so much smaller might make it seem they are hotter while they still give off less heat overall.
Bruce

t5 run hotter than t12 and t8 - the surface area is quite tiny, and the current is pretty substantial - I prefer overdriven t8 - the performance is the same as t5, but cheaper. the surface area of t12 is 12/5 times the area of t5. the surface area of t8 is 8/5 times the area of t5.
t5 draws 55watts and t8 will draw 32 watts, or 50 watts if overdriven. so t12 lamps are very cool, t8 normally is cool, if overdriven gets warm, and t5 is even more warmer. - pm

I found this web site interesting. Many of you probably have seen it before. I use a yellowish/redder bulb and a bluer "grow blub" in a two blub fixture (to hit both ends of the light spectrum). I recall selecting one of the bulbs mentioned on this site. Enjoy!

http://www.waynesthisandthat.com/fluorescent.html

I use t8's to start all seeds, have an old fixture that takes 4 shorter bulbs, 18w each (i'd put stronger but wasn't able to find any at the time, plan to). Stuff like adeniums which require a lot of light survive under that, but they're not the happiest bunch. For seedlings though it works great, just keep in the cool range (6500 K is great) for vegetative growth. Peppers are quite happy, no elongating, but i do keep them at a max 10 cm from the light source.

For starting seeds T5 are more than good. As said above, even T-12s do just fine.