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High PPFD is this ok

Autoflowerdreams

Active Member
PPFD centered 1ft square range at 30 inches is approximately 1050 to 1300. I have no Co2. At 24 inches the PPFD is 1800-2000. Are the plants going to have slow or limited growth? Should I simply raise light and lose out on wider area. The grow area is 3x2x8 ft.

2 Autos 4 weeks old both starting to flower.
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The Bard

Well-Known Member
I'm still pretty new, but I asked a similar question in during my first grow. The advice I got at the time was to target up to 500 during veg, and 1000 during flower (assuming no CO2, as in your case as well as mine). Here's the exchange in my journal. Wishing you good harvests!

600 ppfd is plenty of light for veg, you can go up to 1000 ppfd in flower without co2. I usually run 300-500 ppfd in veg. Maxing out at 1000 in flower.
 

Pennywise

Member of the Year: 2017 - Member of the Month: Mar & Oct 2017, Aug 2018, May 2019 - Plant of the Month: Aug 2017

Pennywise

Member of the Year: 2017 - Member of the Month: Mar & Oct 2017, Aug 2018, May 2019 - Plant of the Month: Aug 2017

The Bard

Well-Known Member
So I just raise the light for less PPFD?
Yes, that would accomplish it. Or does your light have a dimmer control?

The advantage of raising the lights is that you should get wider/more even distribution to the edges of your tent.

Cheers!
 

Barney86

Well-Known Member
It's not something you need to obsess over tbh mate. The vast majority of us just judge it.
Once they've got 5 or so nodes I lower the lights a couple inches every day untill I see signs of stress then raise it a few inches and hold that distance.
If they ain't burning or stressed then it's not too much.
Some strains can take a lot more than others. They're ability to handle light is also largely down to how well your controlling everything else.
Watering regimes, pot size, nute strength, root zone temperature , humidity levels , millions of variables that dictate how much light your plants can handle so best just to judge it imo.

Can get it scientifically "exact" if you like but it's not something to lose sleep over.

Watch your nute strength too. The one on the left is on the cusp. Too much N will slow your growth rates right down.
 

Autoflowerdreams

Active Member
It's not something you need to obsess over tbh mate. The vast majority of us just judge it.
Once they've got 5 or so nodes I lower the lights a couple inches every day untill I see signs of stress then raise it a few inches and hold that distance.
If they ain't burning or stressed then it's not too much.
Some strains can take a lot more than others. They're ability to handle light is also largely down to how well your controlling everything else.
Watering regimes, pot size, nute strength, root zone temperature , humidity levels , millions of variables that dictate how much light your plants can handle so best just to judge it imo.

Can get it scientifically "exact" if you like but it's not something to lose sleep over.

Watch your nute strength too. The one on the left is on the cusp. Too much N will slow your growth rates right down.
The one on the left has always been darker green than the right one being lighter. I was thinking the same thing i only give 1/8 Nutes. but i will continue to watch. Once again this is all new to me as this is my first grow. So to all the members thanks again.
 
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The Bard

Well-Known Member
Still to much light? The plants are really doing well with great growth.
Like @Barney86 said, a big part of this is judgement. I think that you have it dialed in "close enough" given that your plants are doing well. I'd just run with it, and keep an eye on the topmost leaves. If they start to bleach as they get taller, just raise your lights a bit more. To me, lights are kind of like nutes - I try to give as much as the plants can take, but watch for over-doing it. You got this!
 

SmokeSara

420 Sponsor
Those are some high PPFD, but plants don't need too much, during flowering over 1000 PPFD or 2000PPFD actually give you not too much difference. :51:
 
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