Watts VS PPFD: Which Do You Use?
- Thread starter John Ames
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- #grow light #plants
twalte
Well-Known Member
I measure using a lux meter that has been calibrated to work with white LEDs. I learned so much by using a meter and I highly recommend purchasing one. Even a cheap lux meter is better than nothing. There’s a phone app called Photone that seems to get some mixed reviews for measuring light.
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How to Use a Cheap Lux Meter to Increase Yields | Grow Weed Easy
An inexpensive lux meter lets you measure that amount of light at a specific point in space - learn how to use this tool to increase your yields!
www.growweedeasy.com
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StareCase
Well-Known Member
I will use total real watts to determine the size the lights to use for the tent or grow area. LUX/PPFD are then used to measure the actual lighting reaching the top of the canopy.
John Ames
Member
@twalte Thanks for share! This one is only work with white LEDs?I measure using a lux meter that has been calibrated to work with white LEDs. I learned so much by using a meter and I highly recommend purchasing one. Even a cheap lux meter is better than nothing. There’s a phone app called Photone that seems to get some mixed reviews for measuring light.
How to Use a Cheap Lux Meter to Increase Yields | Grow Weed Easy
An inexpensive lux meter lets you measure that amount of light at a specific point in space - learn how to use this tool to increase your yields!
John Ames
Member
@StareCase Do you have standard? For example, How many watt lights you think would be suite for 2x2 ft grow tent? And do you use test instrument to test LUX/PPFD?
coreywebster
Well-Known Member
30w per square foot of quality (efficient) white LED for flowering.
ANC
Well-Known Member
As an example, we make a light using an HLG 320H driver.
It comes in two flavors. One uses 3 bars totaling 45cm (1.5' approx). The wide version uses 4 bars and is about 60cm wide.
The Wide one has more diodes and produces about 55000 lumens vs 52000 on the narrow model....
That being said the narrow one with over 100W per strip punches down deeper into the canopy, even if it does it over a slightly smaller canopy.
With the correct very uniform shallow trained canopy, the wide would be a good setup. with lots of loose large or tall plants, the 3-bar is the better fit...
basically, the wider the source of the photons is spread, the shallower the goldilocks zone of the light will be. In real life, I find the answer is somewhere from about 300 to 450(very high) Watt /sq meter (a meter is about 3 ft). Anything from about 170 to 200ish lm/W diodes (so basically anything from LM561C onwards).
It comes in two flavors. One uses 3 bars totaling 45cm (1.5' approx). The wide version uses 4 bars and is about 60cm wide.
The Wide one has more diodes and produces about 55000 lumens vs 52000 on the narrow model....
That being said the narrow one with over 100W per strip punches down deeper into the canopy, even if it does it over a slightly smaller canopy.
With the correct very uniform shallow trained canopy, the wide would be a good setup. with lots of loose large or tall plants, the 3-bar is the better fit...
basically, the wider the source of the photons is spread, the shallower the goldilocks zone of the light will be. In real life, I find the answer is somewhere from about 300 to 450(very high) Watt /sq meter (a meter is about 3 ft). Anything from about 170 to 200ish lm/W diodes (so basically anything from LM561C onwards).
StareCase
Well-Known Member
For a seed to harvest light, I would recommend ~40 w/sq. ft. For a 2 x 2 - 160 to 180 watts.
I can hear some eyes rolling - but I just use the PPFD Meter app for the Galaxy smartphone then use the HLG LUX conversion factor to calculate PPFD. I just wanna know that I am in the ballpark, as it were.
In VEG, the LUX is ~42,000 and in FLOWER, the LUX is ~63,000. There is no leaf bleaching, tacoing or shielding from excess light with this method. And in the end I get chubby nugs.
ANC
Well-Known Member
I have an 80 cm tent I test small lights in... with a 200W LM561C you can get insane light levels like 70000+ lux so you need to keep an eye on height.
I've used as little as 100W to veg 20 plants probably 3ft long over winter. Currently, I have a 320W system waiting to get hanged in the tent and dimmed but it is occupied making clones right now.
John Ames
Member
Thx!