How close is too close?

reparboon

New Member
lets say a 1000w hps and a 600w hps. how close is too close for the plant? i can easily put a 600hps like 6 inches away from the tops with no ill effect from the buds and the temps are steady around 78-82..(air cooled hood) (i even taped a thermometer to the glass of the hood).. the 1000hps is around 9 inches from the tops of the bud and the same temp around 78-82.. im assuming that if the plants are healthy i could even drop the lights closer?? i see all these tests on different bulbs and led lights and they all test at around 36 inches. is there a reason that there testing at 36 inches? im just curious because i have moved my lights up to 14 inches before and my girls didnt like it and went into shock and got all droopy on me. as soon as i put the lights back to 6-8 inches they perked right back up. i would just like to know if im stunting the growth by having the lights too close and i dont realize it or are they alright being so close without burning them. thanks
 
I wouldn't move it any closer than 18 inches.
 
close as u can possibly get mate. so long as plant isnt showing signs of stress or light burn get it nice and close, dont waste those lumens, it loses so much strength every foot. U want it penetrating deep as it can and get the plant to soak them nutes up. obviously closer u are u sacrifice spread but depends on ur grow style. ur plants will tell u when light is too close. use up the max lumens u can, higher the light= more wasted enrgy and energy the plant wont use.
 
So much easier to burn your leaves when it's really close. You're using an HID ... so you just don't need it as close as you would be a CFL.
 
thanks C.. Mutt like i said they are air cooled hoods so there is no burning or light bleaching of the plant.. i was simply asking how close is too close and if it was wasted lumens/par being soo close that the plant cant use.. BTW Mutt at 18 inches from the 600 bulb the 263500 candle power the light has gets reduced to a mere 13000!! thats 5% of the intensity at 18 inches! im just assuming that is why all the popcorn buds dont develop as much as the top colas... im not sure on the lumens ratio of distance but as per the candle power ratio the light is best closer as it greatly decreases with every inch further away.. if your light is 18 inches from the top of your plants i believe that is way too far for optimum growing
 
And what he said .... LOL
 
i was not asking about a footprint (which im not) SCROG. i was simply asking how close is too close.... theres no other factors like foot print of light.... the question is how close can a 600w HPS and a 1000w HPS be with still being effective and if the lights could be farter away with the same output of the plant (meaning how far is too far where i wont see the same results). CUL answered this with as close as possible within limits of not burning the tops. im still curious if i would get the same output if i moved the lights 10 inches away insted of 6 inches away..
 
im asking because i was thinking about a 5x5 screen instead of the 4x4 screen that would force me to raise the light for footprint.. sooo.. would the 600 hps be just as effective over a 5x5 as it would over a 4x4?
 
no it wouldnt be just as effective but the difference wouldnt be huge. Thats in like for like grows where all conditions are equal apart from room size. the plant will tell u when its too close, if the plant is burnt, bleached or wilted its too much. if its none of those its fine and the plant will be using up that light.
 
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