Do I have too much light?

whoisami · Jul 5, 2020

Hi all. I am trying to become a more informed grower and understand how to maximize my yields. I am currently 3 weeks into the flowering stage of my first grow. I am growing in a 4ftx4ft tent with 3x 240w LM301h quantum boards with . I purchased a lux meter because I read about measuing lux to prevent providing too little or too much light for my girls. With my lights on full power I get about 75k lux at the top of the canopy in the middle and about 50k at the edges. I used an online lux to ppfd convertor (https://www.waveformlighting.com/horticulture/convert-lux-to-ppfd-online-calculator) and based on the calculator that is 1331.9 umols/s/ms2.

Here is where I get confused. I have read up to 85k lux can be okay for you plants. But, above 1000 umols/s/ms2 can be too much light and can burn the plants. So I am under the "maximum" lux but above "maximum" ppfd.

Can anyone help break this down and help me understand?

Thanks in advanced

Merkn4aSquirtn · Jul 5, 2020

How close are your lights? Do they look healthy?

whoisami · Jul 5, 2020

Merkn4aSquirtn said:
How close are your lights? Do they look healthy?

I have the lights about 20in from the canopy. Pretty much all of the plants look healthy, except for one which is a seperate problem. How quickly can I see sunburning? Just look for burnt tips?

pulpoinspace · Jul 5, 2020

if the plants look healthy then its not a problem. but its definitely more light than you need. meanwell drivers are usually good for more power than they're rated, so if they are all on full blast you're prolly pulling 800w+ from the wall.

with a lot of light you boost the plants so you also need a lot of food, a lot of water, and a lot of co2 to keep plants happy. so the symptoms of too much light are deficiencies, skinny top leaves and plant looking overall unhappy.

Cannabis Light Burn & Light Bleaching Symptoms & Solutions!

Light bleaching is similar to bleached hair from spending ample time under the sun. Read for more information on how to prevent and solve light bleaching.

www.growweedeasy.com

1212ham · Jul 5, 2020

whoisami said:
Hi all. I am trying to become a more informed grower and understand how to maximize my yields. I am currently 3 weeks into the flowering stage of my first grow. I am growing in a 4ftx4ft tent with 3x 240w LM301h quantum boards with . I purchased a lux meter because I read about measuing lux to prevent providing too little or too much light for my girls. With my lights on full power I get about 75k lux at the top of the canopy in the middle and about 50k at the edges. I used an online lux to ppfd convertor (https://www.waveformlighting.com/horticulture/convert-lux-to-ppfd-online-calculator) and based on the calculator that is 1331.9 umols/s/ms2.

Here is where I get confused. I have read up to 85k lux can be okay for you plants. But, above 1000 umols/s/ms2 can be too much light and can burn the plants. So I am under the "maximum" lux but above "maximum" ppfd.

Can anyone help break this down and help me understand?

Thanks in advanced

85k lux is a lot! Especially for the less experienced, a little less light is better than too much!
Here's an old post from one of our most respected members, good info in that thread.

Slow yellowish growth under vero 29 3000k/3500k

https://imgur.com/a/uLLbG Updated pics, lights on and off with camera flash. Turned down the lights to 200 watts total and they are 22" above the canopy... I wanna say the clone looks slightly better (back right) but the one on the back left is still pretty light colored with some curling...

www.rollitup.org

Do I have too much light?

whoisami

New Member

Merkn4aSquirtn

Well-Known Member

whoisami

New Member

pulpoinspace

Well-Known Member

Cannabis Light Burn & Light Bleaching Symptoms & Solutions!

1212ham

Well-Known Member

Slow yellowish growth under vero 29 3000k/3500k

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