T5HO What Height?

I've got a 6 lamp T5 light fixture (4x2) and I'm getting some seedlings going, or attempting to. The only thing different about this grow and all of mine in the past is this T5HO light. I had it down @ about 2" and the plants seemed to burn so I raised it to 5". The plants still seem highly stressed so I raised it to 20" per a suggestion on this forum.

I am running just water, no nutes, and the pH is spot in, I've checked it a zillion times and calibrated the meter.

My question is, how high are you guys starting T5HO lights on seedlings? I figured I eventually want the lights down pretty close, but am I wrong thinking that? Are these magical floro's that don't need to be that close?

My plants are like 3 weeks old and they look like they are 3 days old! They are so tiny I'm considering chucking them, ordering new seeds and using my freaking MH to veg new ones. This is setting everything back, I need some help from the floro guys! I know these T5's rock and I really want to use them instead of the MH.

I try not to go more than 8 inches above my plants with fluros.
The farther away, the more stretching you get.
You should go as close to the plants as you can without burning them.

KAL EL said:

I try not to go more than 8 inches above my plants with fluros.
The farther away, the more stretching you get.
You should go as close to the plants as you can without burning them.

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I'm going to run them up just for today and then I'll move them back down to about 8 - 10 inches. If these things don't start taking off it's going to be the trashcan for 'em. I just don't understand what can even be wrong, tiny ass little plants under a good light with just plain water. Simple simple simple and now I've got 12 of them that don't want it to be that simple.

What strain?
If you are not growing F1s, most strains lack the hybrid vigor that makes em grow fast.

KAL EL said:

What strain?
If you are not growing F1s, most strains lack the hybrid vigor that makes em grow fast.

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They are DP White Widow and BB Blue Cheese. These should all be F1's. They are all showing signs of heat stress so I just think they couldn't handle that fixture being so close. I swtiched to 18/6 and moved the light up, hopefully they will start taking off a little here. I hate slow movers and usually would just start over.

I hear ya.

KAL EL said:

I hear ya.

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Man, I ran that light back down for a little while and they started burning and stressing again. It just doesn't make any sense. I was hoping some others who grow with T5HO's could chime in. I put the light up @ 10 inches and I'm seeing no stretching. I'm going to leave it up @ 10 inches for at least two weeks and see what happens. I've ordered new seeds and I'll probably be starting over, but I want to see if these stretch with it at 10 inches. I'm thinking I'll start my next seedlings seriously at 20 inches.

It's not a heat problem. I have a ton of ventilation and a it's never over 80 degrees at the plant level. It's just the light seems to burn the little buggers at the lower levels, crazy.

I'm a newbie as well, but most seedling setups I see with the T5 HO's (including mine) only have 1 2' t5HO bulb and have a 4x setup once they're into full vegg.

Like I said though, I'm no expert by any means..

This is a 6 bulb setup and it's covering a larger area. That really should be the only differnece between this and a smaller one. I need to cover 12 plants.

at least for my seedlings and rooting clones, which are in 2 rows of 6 with 1 2foot t5 HO per row. I origionally had a 4x 4foot setup, which is now in my veg box, and I was having a problem sort of similar. no stretching, and the fan tips burned with 0 nutrient setup. Dunno.. I just prettymuch copied most of the setups I could research. Don't have many grows under my belt yet