Leave Autoflower Light Intensity at 50%, or Increase as you Would With a Photoperiod?

One of my gurus (Welcome to the Grow Tent on youtube) said in one video to not increase past 50% intensity for autos...
My other guru says, hell no, turn them dang lights up to 100% by week 3 of Flower!

What should I do??? My plant looks great at 50% intensity LED in week 8.

I have a VIPARSPECTRA 1500xs Pro Series

I tried increasing to 75% awhile back when the plant was smaller, but it seemed to heat the tent too much, because when I looked a few hours later, the leaves had suddenly drooped!

I just dont waant to kill ANOTHER PLANT, lol!!!
 

Phytoplankton

Well-Known Member
Well you could split the difference and go 75% (lol). I’d go with 90-100%. I’ve never heard that autos had a problem with high intensity light. I run mine 100% unless I run into height issues, then I’ll scale it back to avoid burn. I have a photo grow going now, but am only running.70%. Because they got too big, I can’t raise my light any higher, and I don’t want to HST 20.-30 colas.

Edit: Anyone can make a video or blog, doesn’t mean they know what they’re talking about.
 
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Thanks Phytoplankton!!!
Maybe I'll bump it up to 75% tomorrow and see if the leaves are still praying all day. I think perhaps the issue when I turned the light up before was that I was not keeping the reservoir topped off on a daily basis. So when I increased the light, the plant sucked up the water in the rez and drooped for that reason!
If that was the case then I just better refill the rez twice a day. I'm only using 1 gallon roughly in the rez when it's full, maybe 1.25.

One last issue is that at this point there is only about 12 inches between the light and the top colas. This seems like a risky distance for increased light.
You have made me feel more brave about this. Will report how it went.
 

Dorian2

Well-Known Member
I run mine at 50% for seedling then continue to adjust until it's at 100%. Your light has the same draw from the wall as my 2 lights at 150W in a 4x2 tent. Adjust as necessary.
 

Phytoplankton

Well-Known Member
Thanks Phytoplankton!!!
Maybe I'll bump it up to 75% tomorrow and see if the leaves are still praying all day. I think perhaps the issue when I turned the light up before was that I was not keeping the reservoir topped off on a daily basis. So when I increased the light, the plant sucked up the water in the rez and drooped for that reason!
If that was the case then I just better refill the rez twice a day. I'm only using 1 gallon roughly in the rez when it's full, maybe 1.25.

One last issue is that at this point there is only about 12 inches between the light and the top colas. This seems like a risky distance for increased light.
You have made me feel more brave about this. Will report how it went.
You omitted a couple things, your light says hanging height is 14 inches. Don’t kick it up all at a once, do it over a week or so.
 
You omitted a couple things, your light says hanging height is 14 inches. Don’t kick it up all at a once, do it over a week or so.
ok, thanks! I. am in a 2X2X4ft tall tent by the way. For most of this entire grow I tied the light to the top of the tent to see if it would still work, as recommended by the guy on the Welcome to the Grow Tent channel on youtube. So I was perhaps at 36 inches above the canopy, and just let it grow until now where I have the light a foot above my colas! So I ignored the manufacturer's advice to be honest.
 

Phytoplankton

Well-Known Member
Be careful about putting your light too close to the top of the tent. Most lights have a minimum amount of space you have to have between the light and tent roof, fire danger!!!
 
Be careful about putting your light too close to the top of the tent. Most lights have a minimum amount of space you have to have between the light and tent roof, fire danger!!!
Yes, good warning! I have tried feeling for warmth on the back side of the light and not found any yet. I am excited to be moving into a tent with an extra foot of space which should help keep a good distance up there :) Luckily there is a tent pole keeping the light a couple inches from the canvas.

Stop watching YouTube
Have you checked out the Welcome to the Grow Tent channel? Dude is head and shoulders above other channels. By following his directions I saw my plant finally flourish after basically screwing up my first 3 tries because of putting light too close and other mistakes newbies make ;)
 
i have decided that since there is only 12 inches between colas and light that there just isn't enough space for even 75% light intensity. I think the light would fry the buds and incinerate the trichomes.
I will finish this run on 50% even though I wish I could bump it up to 75% or 100% if I had one more foot of height in this FREEKIN 4 ft tent !!!
The buds look pretty dank though, so maybe Welcome to the Grow Tent was right after all?
 

Rocket Soul

Well-Known Member
OP: youre correct in that autos on longer hours dont need quite as much light intensity as photos. But the amount is not something you can get by asking people online, you need to read the plant. Nobody will be able to tell you how much to give without a few images of the plant in question and some info on hangheight and such.

Generally on led light intensity: when raising intensity you may wanna add a little heat (sometimes the light heating up a bit more is enough) and depending on how the plant looks and reacts; up the feed a bit.
 

Rocket Soul

Well-Known Member
Looks like quite happy plants but you have tip burn on most leaves, are you feeding too much?

It could also be from over transpiration when you turned up the light but not too sure; it goes counter to leaves becoming droopy when raising temps and light intensity.

Vipar 1500xs : this light has too high light levels (generally speaking, theres always exceptions) for an auto on +18hours of light on when hung at manufacturer recommend height and kept on 100% intensity.

75%: when you tried this, and then had a look and saw droopy leaves; why do you think it was the heat and not too much intensity which made the plant droopy? What was the te.prature difference?
 
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