How much light do i need
- Thread starter m99smith
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TintEastwood
Well-Known Member
What Size Grow Light Do I Need? (The Simplest Way To Figure It Out)
Determining what size grow light you need can get a bit complicated. It depends on so many different factors, but I show you how to simplify it and make the...
growlightinfo.com
Ok thank you so I have enough light that's goodWhat Size Grow Light Do I Need? (The Simplest Way To Figure It Out)
Determining what size grow light you need can get a bit complicated. It depends on so many different factors, but I show you how to simplify it and make the...
ChiefRunningPhist
Well-Known Member
That's quite a bit. Probably overkill.
Assuming a COB efficiency of 2.27μmol/J, uniform distribution, and a grow room reflectivity at 100%, 1000W of COB in 16ft2 area is...
(2.27μmol/J) × (1000W) × (J/s·W) × (1/16ft^2)
=
141.8μmol/s·ft2
(141.8μmol/s·ft2) × (10.76ft2/1m2)
=
1,526.5μmol/s·m2; ~1,526.5 PPFD
Past about 800PPFD you get into an area of diminishing returns. If they can be dimmed then I'd run them closer to ~60% power, and if they can't then I'd only use 3 and hang them high.
Id shoot for "lights on" conditions of 83°F and 55% RH ideally, else within a temperature range between 81°F/27°C - 86°F/30°C and a matching RH range between 50% - 60%.
Good luck
Oh well each light has 2 50w cobs and the rest are normal leds so 400w in cobs and 600w of the normal ledsThat's quite a bit. Probably overkill.
Assuming a COB efficiency of 2.27μmol/J, uniform distribution, and a grow room reflectivity at 100%, 1000W of COB in 16ft2 area is...
(2.27μmol/J) × (1000W) × (J/s·W) × (1/16ft^2)
=
141.8μmol/s·ft2
(141.8μmol/s·ft2) × (10.76ft2/1m2)
=
1,526.5μmol/s·m2; ~1,526.5 PPFD
Past about 800PPFD you get into an area of diminishing returns. If they can be dimmed then I'd run them closer to ~60% power, and if they can't then I'd only use 3 and hang them high.
View attachment 4429772
Id shoot for "lights on" conditions of 83°F and 55% RH ideally, else within a temperature range between 81°F/27°C - 86°F/30°C and a matching RH range between 50% - 60%.
Good luck
And my room is at 68f to bring out colors and around 65% RH I will have to get a dehumidifier soon cuz it's only week one of flower and the RH will just go up
ChiefRunningPhist
Well-Known Member
With a mix of COB + mid power LED you're probably getting even more light than calculated up above per watt of input (if higher efficiency products are used). I'm not sure what COBs or what mid power LED, or what the efficiency of the powering solution is, but if they are middle to high end then I'd still imagine 3 would be plenty, the previous post & calc was based around higher quality COBs or higher efficiency COBs.
If night temps are dropped you can achieve "colors" as well. RH drops as ambient increases, so if you were to raise ambient during the day it might help your RH? Exhausting works well too and is good for circulation along with RH control. If you were to increase the temp even more than 68F they'd grow even faster, but 20C/68F will grow the plants and to each his own.
Here's a little chart showing the photosythetic rate of cannabis (Y-axis) vs the leaf temperature (X-axis)...
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diggs99
Well-Known Member
Whats up chief,
I Seen your name on the main page for last to comment, figured this morning was a good time to learn something, you never let me down bro.
Ok thank you this helped me out a lot
ChiefRunningPhist
Well-Known Member
Lol thanks man appreciate the comradery.