I got a light with T5 lightbulbs. I took the two diffusers off, it looks like I got more light this way. Is it ok for my fig tree or diffusers has to be there? 

If your talking about the platic shield or glass. That what i did and i keep it 10 inches awY

To me diffusers equal garbage... unless.... you have HQI metal halides, then the glass is a must.  LED's, florescent or mogel base metal halides, they are not needed. 

Scott

Agreed, not needed.  I removed mine and they provided a slight bit more heat, which was helpful.

Oh cool, thank you. I am currently have one fig tree that is uses light because it was dying, the other two that I have don't need an extra lighting, they grow fast and look fine. If I will get them an extra lighting for a few month will those trees get used to and then lets say i will take that extra lighting away, are they gonna die? This is one of those that grows without extra lighting.

Less light means less plant energy and leggy weak growth.  They may not die, but they will be very weak and will require very gentle acclimation to real sunlight next spring.

So, what you are saying is to get more more light to my two trees that grow fine without a lot of light? 

Yes, that is what I would do.

Ok, thanks. But look whats happening with leaves now after 12 hours under light. Look at two leaves that closer to you, the back one was like that before.  

I have T5 lights a couple of inches away from my figs.  The only time I got leaf wilting was when I didn't water it enough.  It looks like the roots aren't pulling enough water for the top of the plant, either due to the potting mix being too dry or there just not being enough roots to support the plant. That's my guess.

[edit: T5 not T8 lights]

Ok, I will water it, see if it will make changes

The picture you posted shows the fig with week leggy growth, I would get a high intensity light over it plus put it in a South West facing window.

JMO

Its near window facing South. I can't provide light on South West side. So, low light cause weak leggy growth?

Yes, the plant is stretching trying to grow out of the shadows and into the light.   Out doors they live in full sun all day, indoors they just don't get enough light with supplemental high intensity lighting.  typical house plants are understory plants that live in the shadows of trees and other plants I prefer full Sun that is why they do OK in most homes because they need filtered light not direct light.

This is why we find a a cool place for the trees to be dormant but warm enough that they won't be damaged by the hard freezes of winter. The trees are far better to go dormant and actually require a dormant period.  This is why everybody goes crazy over the winter, we're waiting for spring so our trees can come back to life.

You may consider placing the tree in the garage or cool basement restrict the water to once every 3 or 4 weeks and allow the tree to go dormant, the indoor lighting will Then no longer be an issue.  Then come spring get ready to move it back out into full Sun.

Sorry, i just realized that FiggyFrank already answered my question about week leggy growth. Thank you. I don't have a garage, I live in condo, they will die outside, I am in zone 6. I will just provide light for them as much as I can during winter, thats all I can do...

Do you have an outdoor storage closet with a light or receptacle?  If so, you could put the tree in it for its dormant period, then use an incandescent light or small heater to stave off the worst of the cold. 

No, I don't have anything like that.. I might figure something out for the next winter.. How bad to have my fig trees under 2 T5 lightbulbs for another 2-3 month. Are they gonna die? One of them has a little fig on it.

Are the T-5's standard, HO  or VHO?  They won't die, but they will need to be hardened off real slowly come spring.  The transition to full sunlight will be real difficult for them. There is a good chance they will defoliate.

I couldn't find anywhere where it says VHO or HO. I only found says 6500k. Is that VHO or HO? Which one do I need.

No, just standard.  HO stands for High Output and VHO is Very High Output. You have to go out of your way to find those lights. 

You'll be fine with the standard, just keep it as close to the tree as you can plus as much sun as possible. 

Ok. Thanks for all the help.