It's pretty simple shit dude.
Light energy is a release of photons. Only so many photons are available at a certain distance from the lamp. We measure them with meters and you know them as lumens. The rule of squares says that for every increase of distance by "1" the concentration available is decreased exponentially.
At a distance of "2" there is 1/4 the energy available. At a distance of "4" there is 1/16th the energy available, and at a distance of 10 there is 1/100th.
What determines the distance of "1" is the lighting type. HID bulbs are measure at just under 7 inches from the lamp. Fluorescent bulbs are measured at closer to 3 inches from the bulb.
So at a distance of under 30 inches from a T5 system you are working with less than 1/100th of the lumens advertised.
Perhaps you can for some reason decide to vegetate a huge mother plant under a T5. The plant will grow, I'm not disputing that. What I am disputing is that if this guy would like to grow bud, top to bottom, then he needs a better system. Your plant is a mother plant in Veg for a reason and flowering with that system would be artarded. Way to post something that will only confuse people for a long time.
Rule of squares. Learn it. Live it. Love it. It's light physics and it cannot be disputed. The light can only activate photosynthesis if it is strong enough. You get too far from the bulb and you can't grow anything decent.