How close to put LED to plants?

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The manufacturer has done very extensive research on that light before they sold it to you. Go off of their recommendations. Move the light in 2 inch intervals. Wait to see the results over several days..
 
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Much appreciated!!! I have it at about 18-20 inches now, so raise it up a couple? I have fans on them and the room temp is 77 degrees.
Your light recommends that you have the light at 24 inches to be able to cover a 3 by 3 evenly any closer and your area will shrink. For a Seedling it would be more like 30 inches away. To be honest your seedling would be a lot happier with just a 25 watt CFL in 6500k plus you wouldn't be burning a bunch of unnecessary Electric. You could probably get that plant 6 or 8 inches tall on one little CFL keeping it 6 inches away.
 
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Your light recommends that you have the light at 24 inches to be able to cover a 3 by 3 evenly any closer and your area will shrink. For a Seedling it would be more like 30 inches away. To be honest your seedling would be a lot happier with just a 25 watt CFL in 6500k plus you wouldn't be burning a bunch of unnecessary Electric. You could probably get that plant 6 or 8 inches tall on one little CFL keeping it 6 inches away.
I always start off my plants with 4 6500k cfl's and had no problem with them growing. I grow 2 plants at a time because of space. It seems to work well.
 
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Much appreciated!!! I have it at about 18-20 inches now, so raise it up a couple? I have fans on them and the room temp is 77 degrees.
canopy and root temps are critical, UV radiation passes through air and so dont show on standard room temp gauges.. leaves will be hotter than the air by nature of UV. Try to get a laser temp thing, this will allow you to consider the warming effects of UV.

look at Vapor Pressure Deficit and understand how changing one variable means you must adjust others
 
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Some stretch is not a bad thing depending on what your growing.

"·Core Coverage at 24" Height 2x2ft"
"Max Coverage at 24" Height 3x3ft"

from Amazon the above specs...so everything is at 24"...hmmm
 
Since your grow light is a high wattage LED, it needs to be hang about 30'' above the plant. If my memories don't fool me then there's always information on how far you should keep the light away from the plant written on the product. Maybe you should check it for the best answer.
 
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Since your grow light is a high wattage LED, it needs to be hang about 30'' above the plant. If my memories don't fool me then there's always information on how far you should keep the light away from the plant written on the product. Maybe you should check it for the best answer.
Your right!!! I just checked and its 24-26" above the tops. In flowering its 18". Thanks for the reply. Peace Out..
 
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I've had mine a lot closer than 18 inches with no problems. Every unnecessary inch further away is less light for your plants. Experiment, your plants will tell you if you're too close before any irreversible damage is done. Of course, too close and you're not getting the coverage. The last thing you want to do is follow manufacturers guides on anything. Nobody has told your plants about those guidelines, they don't follow set rules, every plant is different.
 
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I've had mine a lot closer than 18 inches with no problems. Every unnecessary inch further away is less light for your plants. Experiment, your plants will tell you if you're too close before any irreversible damage is done. Of course, too close and you're not getting the coverage. The last thing you want to do is follow manufacturers guides on anything. Nobody has told your plants about those guidelines, they don't follow set rules, every plant is different.
I agree!!!
 
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It all depends on the unit's heat output.

At full-draw [800 watts] my SolarSystem puts out 2500 BTUs. Average HPS setups run at about 3400 BTUs. Manufacturer recommends 24-inches from the tops.

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