maximum lumens per sq foot

hello my current setup is a 600w mh/hps gull wing hood with reflective mylar for the walls. a single box fan is blowing over the light and is keeping day temps at 77-75 and night temps at 72 when its off. I am using 1 plantar tha holds 5 gallons of soil with a blueberry plant that has been lst'd mildly and received mychorizzae during initial planting. it has been given superthrive every watering as well as no nutrients the first watering, 5-1-1 fish emulsion as well as 1 tbsp molasses and a tsp of 1-3-2 Alaskan seaweed throughout vegetative, and 2-15-6 bat guano with 1 tbsp molasses from beginning of flower until now.also nutrient solutions were aerated with a 30 watt gang valve airpump with 6 inch diameter bubble disc for minimum of 3 hours max of 2 days. plant was revegged blueberry plant harvested in late January put into reveg on January 29. had it in 24hr light from late January til april 21. plant was given 3 days of darkness and light cycle was switched to 12/12 on april 24. light meter measures 7457 lumens per sq ft at very bottom of leaves and measures + or - 40 lumens per sq ft deviance of 7457 lumens/sq ft around diameter of lowest leaves. top of canopy measures 24000 lumens/sq ft . light is 16 inches from top of canopr

now that you have some back ground information my question is how many lumens per sq foot is too many?

you're fine

Kite High said:

you're fine

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are you sure I read somewhere that ed Rosenthal states that over 18000 lumens per square foot can bleach the leaves can anyone confirm this? I posted this for clarification but im almost certain that 24000 at the top of the canopy is too much

you can never have too much im sure this is not actually true but i think you will be fine with what you have. If your leaves start to bleach just raise the light and the lumens will decrease.

Well,youre just using the one bulb right? How could one 600 watt bulb be too many lumens per square foot, especially when they make 1000 watt and even 1500 watt grow bulbs now. Too much light is usually only a problem when people use multiple lights in a small area and/or the bulbs are too close to the plants.

applepoop1984 said:

are you sure I read somewhere that ed Rosenthal states that over 18000 lumens per square foot can bleach the leaves can anyone confirm this? I posted this for clarification but im almost certain that 24000 at the top of the canopy is too much

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Fuck Rosenthal. He's a pos

I've had the tops of buds go pure white when I got too close.

cues said:

I've had the tops of buds go pure white when I got too close.

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Opps , been there before haha lol .. White Ganja

BustinScales510 said:

Well,youre just using the one bulb right? How could one 600 watt bulb be too many lumens per square foot, especially when they make 1000 watt and even 1500 watt grow bulbs now. Too much light is usually only a problem when people use multiple lights in a small area and/or the bulbs are too close to the plants.

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the hps bulb is rated at 86000 lumens, and at the top of my canopy the light meter reads 24000lumens. the light is about 18 inches from, the plant

i asked the same ?

60k lumens is the maxium and 5k lumens is the lowest .......u are 24k then u should be set for a good yeild


if u a worried about under light .....cfl bulbs can get with in 2 1/2 inchs and cuase no damage to plant........u could use a power strip and outlet to sockets and space the plants out more put that down on the ground to get the under leaves ( ones u think are getting to little becuase of other leaves taken it )
socket to outlet 2.50 each
power strip
blub will run yah 5-7 bucks u get about 1600/1200 lumens off them

It's been eluded to that of heat is controlled then 40k lumens is tolerated. Personally IME 20k is ok 15k optimum and 2k will still produce some growth. Below 2k growth stops. Above 20k growth slows.

I like 6-7500l/ft at the base range of my scrog screen (at the screen, that's were I veg and then the buds grow up through).
It depends on what you call optimum. Most harvest, best use of space or a combination of the 2.

I use a 10 x 10 with 4-1000s.... each bulb is 110,000 lumens... so im running 440,000 lumens or 4400 per sq ft.....anything above 3000 is good for a garden

Right now I have a 1K super sun HPS light in a 2.5'x2.5' growlab. 2 plants are 3 weeks into flower. Light is apprx 18-20" from canopy and they LOVE it! Not sure how many lumens that is a square ft but there definitely are no signs of stress or bleaching!

colonuggs said:

I use a 10 x 10 with 4-1000s.... each bulb is 110,000 lumens... so im running 440,000 lumens or 4400 per sq ft.....anything above 3000 is good for a garden

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by those calcs I am at 6000.....always can be adjusted by distance from plants so as long as adequate heat control they GROW