I live in Houston. I am a noob when it comes to all this. I started off indoors like 3-4 months ago. I just recently bought these T8 lights and I have these Philips Plant & Aquariums light bulbs on them. I just got another T5 fixture my friend have laying around. They are a HO 39W bulb blue, purple & white.

I think they have been indoors too long now but, the stems don't look thick enough yet.

thick strong stems and bushy plants come from 1) close, high output light and 2) wind

lights have to be very close and put a fan on them so there is a constant breeze.. this works best when you start doing these things when they are still really small. it might still help to add a fan though.

and again, lights should be very close. for a T8, i would guess no more than 4-5 inches away..

I keep them closer than that, about 2". T8s don't get hot enough to damage leaves on any plant I've used them on should they happen to come in direct contact with the bulbs. T5s would though.

I keep T5HOs 2" from my succulents, it's not too hot. Some leaves are even just 1" away and are not damaged.

There is a fan blowing constantly though. Surface temps on warm days outside currently range between 25C and 41C indoors in my grow area. Monitoring temps of the leaves is pretty important.