How many lumens is too much?

GodfatherKCCO

Well-Known Member
So he did a search and upon reading the results came up with a question. Problem? In fact, he probably would have been blasted and told to do a search if he had asked directly.

I'm glad he did too. I have access to LED lighting that's usually used on parking lot poles at 20 to 30' in the air and that was a concern for me as I'm pretty much going to use a 3 x 3 or 4 x 4 space initially until I can afford to build a mini grow system. The amount of light available is an actual concern for me.
 

metalback

Member
Your plants will tell you if you are giving them too much. Leaves on top will begin to turn white. Just increase the distance from the plant. I'd highly recommend an LED. They produce little heat, and save money on electric. $160 for a King Plus 1000 watt, $145 for 800 watt. LED made everything easier.
 

GodfatherKCCO

Well-Known Member
Your plants will tell you if you are giving them too much. Leaves on top will begin to turn white. Just increase the distance from the plant. I'd highly recommend an LED. They produce little heat, and save money on electric. $160 for a King Plus 1000 watt, $145 for 800 watt. LED made everything easier.
cool.. thank you
 
hi that what look like when too many light but that the first time that do that ,leaves on top are yellowing and fade ,i use a 600 watt mh apollo at one meter and humidity 60% heat 23.5 and vent in out... and even under my 2000$ platinumled p1200 at 48 inch! that do the same, theyre are ok under cfl.. my other grow i used 1000watt hps at one meter to start to finish without that shit ,i dont now if the new batch of brother grimm cinderella99 and green avenger(apollo11 like) are very sensitive,i now i need to put them in bigger pot they are 2 week old ,so i think its the last day under 600w mh or led light or using my dimmer to reduce the light to 250watt,im gonna try to take a clone of each if they survive,i forget to say that one of the green avenger is perfect nno leave fadding or yellowing.
 

Attachments

Last edited:

Billiam76

Active Member
How many lumens per square foot is absolutely too much for a plant? I know it may very with seedlings and clones and what not, I am wondering for strong plants, around 1 foot tall, what is the absolute highest lumens you can put on them, or is the only limit the heat you produce with the lights?
Actually plants don't use 'lumens' ; the better measurement is PAR, none the less it is useful for my lazy purposes to use watts per square foot. A good place to start to really understand your underlying question is here: http://www.windows2universe.org/earth/climate/sun_radiation_at_earth.html
I am informed and believe that a well run research greenhouse has about 250 watts per yd square supplemental HPS lightning (about 27-28 watts/sq ft. This assures plant growth without regard to weather.
 

twalte

Well-Known Member
I just purchased a lux meter to measure my 1000w MH bulb and I found that I was greatly exceeding the recommended levels from Grow Weed Easy by running over 105k lux in some spots. See below for their recommendations.

Quick Guide - Lux Levels for Optimal Cannabis Growth

Life Stage Maximum Good Minimum
Vegetative
70,000 lux 40,000 lux 15,000 lux
Flowering 85,000 lux 60,000 lux 35,000 lux
< 15,000 lux - sparse or "stretchy" growth - plant isn't getting enough light
15,000 - 50,000 lux - good amount of light for healthy vegetative growth
45,000 - 65,000 lux - optimal amount of light for cannabis plants in the flowering (budding) stage
70,000 - 85,000 lux - a lot of light, some strains do okay at this light level, but some plants lose their top leaves early under this light intensity, especially plants that are not resistant to heat/light (like many indicas)
> 85,000 lux - at this light intensity, you've hit the plant's "saturation point" which means your plant can't use all the light (be careful of light bleaching!)
 

Budget Buds

Well-Known Member
I just purchased a lux meter to measure my 1000w MH bulb and I found that I was greatly exceeding the recommended levels from Grow Weed Easy by running over 105k lux in some spots. See below for their recommendations.

Quick Guide - Lux Levels for Optimal Cannabis Growth

Life Stage Maximum Good Minimum
Vegetative
70,000 lux 40,000 lux 15,000 lux
Flowering 85,000 lux 60,000 lux 35,000 lux
< 15,000 lux - sparse or "stretchy" growth - plant isn't getting enough light
15,000 - 50,000 lux - good amount of light for healthy vegetative growth
45,000 - 65,000 lux - optimal amount of light for cannabis plants in the flowering (budding) stage
70,000 - 85,000 lux - a lot of light, some strains do okay at this light level, but some plants lose their top leaves early under this light intensity, especially plants that are not resistant to heat/light (like many indicas)
> 85,000 lux - at this light intensity, you've hit the plant's "saturation point" which means your plant can't use all the light (be careful of light bleaching!)
Lux is a poor tool for determining the growing potential of a light, lumens (lux) are a measure of light visible by the human eye and not the usable light a plant can use to grow. Par (watts) are a more accurate method of determining growth abilities in plants,PAR watts directly indicate how much light energy is available for plants to use in photosynthesis , that being said a google search of par will tell you everything you need to know about it . For the old schoolers out there , 5k + lumens per foot square is the standard for giving plants optimal growth, The only time I have ever seen bleaching is from a 1 k hps with super good airflow placed about 10 inches above the canopy of a group of plants, Or several times with hi quality diy led lights .
 
Top