New lights

[Gingerbeard]

I'm transitioning from vegging in T5's to LED's in a couple days. It's a dimmable 350w Viparspectra going in a 2'x2'x4-1/2'. They'll spend another week or two getting some more height until going 12/12. Each plant was raised to 10ish inches tall under HPS and given to me at 3ish weeks. They will have spent the next 29 days under the T5's.
When I make the switch is there a fair level I can dim to keep from shocking the plants with too much or too little light?
The photo of the roots is from transplanting the topped plant. The snow in the one picture is of diatomaceous earth on another I'm spiraling. These are getting LED'd.

[starramus]

I wouldn't dim the LEDs at all. Which T5 fixture do you have? You might just continue with the T5s until switch.

[ZigZag]

I know no nothing about T5's....but when I bring my lights up to full power I start them up high and lower an inch every day, unless they start to show signs of heat or light burn/exhaustion. Since I have done about 6 grows with the lights I'm using now I have the height thing pretty well dialed in for whatever stage of development.
You don't have a lot of headroom so you don't want them to stretch much once you flip to 12/12 so keep the light as close as possible.....but I'd start with at least 28-32" and take it down slowly. Then if you run out of headroom later you can dim the light if needed. Just keep an eye on them a few times a day at first if possible.

[Gingerbeard]

Looks like Viparspectra expected my question about dimming lights. It's not a big deal. Go with the flow. There's a chart on distances and intensity and such in the instructions.
I want to move along with more powerful lights for the vegging. I'll give kudos to the type of light (T5) but hold the brand just now. One of two has turned out to be a bum unit. The company is real keen on getting me taken care of. I've put off returning the bum unit until I can get going with the LED. When all is smoothed out, I'll name names.
I put mine 2" from the tops of the leaves when they get turned on. That's more than enough for a growth spurt without sunburn. There is an intake fan right above the top of the space, above the T5. That fan is way plenty to keep the inside at a good temperature.
I'm digging the idea of a perpetual harvest. If I keep with seed I'm hoping to get a little something-something every five weeks. Cloning will need more prep in the veg chamber.

[ZigZag]

Once you get the LED you won't need to worry about losing spectrum from dimming. If you're working with limited head room and growing plants >3' tall then having the fall back feature of being able to dim can save your butt in some circumstances. Its a nice fallback to have and you can get your light down low over seedlings and keep the intensity down as well.

[Gingerbeard]

Update to the bum light fixture:
The brand of the T5 is Sun Blaze. One of two fixtures needed to be returned. I bought the lights through Hydrobuilder. Think what you want about that.
I will buy what I can through Hydrobuilder because of Cami, Erin, and Edson. Cami was my salesfolk and was moments in replying when I let he know I had a problem. Erin (the return folk?) was also moments in sending me return info. Edson-folk gets his own kudos.
One of two of the Sun Blaze T5's was returned. As far as I can tell, otherwise, my plants dig the light and I will get another.

[Subliminal]

Using your dimming can reduce your light spectrum as much as 90% and reduce the longevity of your actual bulb. I'd just go 100% and adjust for height and heat.

[Budler]

I’m using my 900w viparspectra from seeds on autos. I’d put all my lights on those girls. The led from the top and the t5’s maybe from the side or you can use those for the clones I guess (never done that)
that led draws about 130w if it’s similar as mine.

[Gingerbeard]

Good news! My plants didn't turn into tomatoes! 100% power didn't make any overnight mutations!
I'm going to look for another 8"-10" of veg before going 12/12 with the LED. That's assuming I'm going to doubleish plant size when flowering.
I'll also look for another T5 before my next new set. A single bulb for the newly rooted and two for the mature vegging. Supplemental light in the LED chamber has been a consideration since the get go. I'm not sure I'll need more than 350 watts in a 2'x2'. I may have a different opinion after a grow or two.

[ZigZag]

Yes! That's a good start_ tomatoes don't smoke that well unless your making salsa! Cheers for an awesome grow, I'd give them another two weeks in veg too.

[Gingerbeard]

Tomacco. You get me. Google tomacco if you don't. I get partial credit.

[ZigZag]

HA! I'll do that!