Is my light Too Close to the plants?

BiG $m0k3

BiG $m0k3

Active Member
I showed this picture to a guy that works for a grow store today, and he said the lights are way too close. It's a 750 watt KIND LED light. Jorge Cervantes said I could put the light one foot away from the plants. He also said if you can put your hand under the light without your hand getting burned then your plants should be good at that height. Anybody have any input?
 

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ttystikk

ttystikk

Well-Known Member
Too many unknowns, like chips and performance.

I have lenses on my COB LED lights, I keep them a foot off the plants.
 
SPLFreak808

SPLFreak808

Well-Known Member
Dimensions: 23in x 17in x 3.5in
Weight: 28 lbs.
Actual Wattage: 430w
HID Wattage Equivalent: 750w
Total Diodes: 208
Diode Wattage: Perfect Mix of 3w & 5w
Footprint: 4 ft x 4 ft
Input Voltage: 100-240V AC Power Input
Work Frequency: 50/60 Hz – Suitable for Global Energy Environment
Output Voltage: UL Standard Output Voltage – Less than 76V DC
Amperage: 3.58
Kind Factor: 10/10

Just be careful putting it too close to tiny plants/clones.
 
Resinhound

Resinhound

Well-Known Member
The whole put your hand under the light and if it doesn't get burned is Bullshit and advice from a bygone Era IMHO. You can easily stress plants with intensity while feeling little to no physical heat.

In nearly all cases with small plants you want your light higher as long as you aren't stretching. The most important things to watch for are leaf margin curl and excessive stem growth. If your leaf margins are curling you are too low, if you see excessive stem growth with less foliage you are too high.

Those plants look kind of sickly, can't really see the condition of the leaves but they do look kind of stretchy, although that sometimes is par for the course with cheap inefficient diodes like those used in the kind.
 
H

harris hawk

Well-Known Member
use the "back-of-hand-test" : once at desired height put hand over the top of your tallest plant - leave for about 1-2 minutes if your hand (top) get/feels too hot - raises light - consider 12-16 inches above plant
 
MeJuana

MeJuana

Well-Known Member
Yeah you can't be using a huge light on tiny plants because it heats the medium up too much. If you insist on using such a large lamp then you need to take action to insulate the soil/planter. But you are paying a premium for your smoke at this point because most of us use a couple cheap fluoros for small plants like that.
 
BobCajun

BobCajun

Well-Known Member
Yeah it is pretty wasteful to use 430w on something that could do fine with 1/4 of that. Extra light just means more heat and more water usage because they will dry fast. I just use CFLs for cloning and veging. CFLs do have a place in modern growing, just not for flowering. I always position them horizontally with an aluminum reflector over them, which I make from disposable aluminum cooking pans, the rectangular ones used for small lasagnas and stuff. Just have to cut a notch at the back and fold it up, then push the notch down over the socket and zip tie the flap to it.
 
MeJuana

MeJuana

Well-Known Member
I don't like to argue so normally I avoid matter of factness when I post. But I've got plenty of money to use HID lights in my veg room I don't do this because using fluoros to slowly build a plant gives me a better yield from a plant with much thicker stems. Stem size is related to yield that is a simple observation. Additionally a veg room with fluorescent lights doesn't need air exchange that's a stoner myth, sorry fan companies I just said it. My 2 veg closets are completely sealed with 1 stand mounted oscillating fan (each) that doesn't even blow the plants it blows against the wall. No powdery mildew, no problem with growth and since my home is cooled by a huge central a/c unit the fluorescent lights don't need special cooling practices. I do run 2 veg rooms because I am always worried about Powdery Mildew since I had it about 7 years ago but I got rid of that Strawberry Cough pheno which was prone to it and never seen it again. For those using Google to find my post you may want to know my home is cooled to 69F in the summer and heated to 66F in the winter where my veg closets run year round as described above. So there it is there, again I am not here to argue so if you are so convinced you need HID lights and air exchange then by all means "grow the right way".
 
HydroRed

HydroRed

Well-Known Member
ttystikk said:
Too many unknowns, like chips and performance.

I have lenses on my COB LED lights, I keep them a foot off the plants.
Click to expand...
^^This exactly, along with room temps etc. I have 400W of cxb3070's and I have them approx 9-10" off the top of the canopy with no issues. Cant say I could have done the same with my 1000W HPS. Lots of variables to consider for the OP's question.
 
BobCajun

BobCajun

Well-Known Member
MeJuana said:
I don't like to argue so normally I avoid matter of factness when I post. But I've got plenty of money to use HID lights in my veg room I don't do this because using fluoros to slowly build a plant gives me a better yield from a plant with much thicker stems. Stem size is related to yield that is a simple observation. Additionally a veg room with fluorescent lights doesn't need air exchange that's a stoner myth, sorry fan companies I just said it. My 2 veg closets are completely sealed with 1 stand mounted oscillating fan (each) that doesn't even blow the plants it blows against the wall. No powdery mildew, no problem with growth and since my home is cooled by a huge central a/c unit the fluorescent lights don't need special cooling practices. I do run 2 veg rooms because I am always worried about Powdery Mildew since I had it about 7 years ago but I got rid of that Strawberry Cough pheno which was prone to it and never seen it again. For those using Google to find my post you may want to know my home is cooled to 69F in the summer and heated to 66F in the winter where my veg closets run year round as described above. So there it is there, again I am not here to argue so if you are so convinced you need HID lights and air exchange then by all means "grow the right way".
Click to expand...
I use CFLs in a 3' high cabinet that I use for veg. I cut some holes in the top and drilled several in the bottom of it, which is raised a few inches from the floor. The heat of the CFLs causes a chimney effect which provides sufficient air flow. No mold, not excessively hot, works fine. I only have three 40ws in there though, for a 3'x1.5' area. That's over 25w per sq ft, so it's plenty.
 
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Muleskinner

Active Member
you have to experiment, no way to know how the light and ventilation, temp, soil medium, etc will affect how much light the plant can take.

But 430 watts of Kind LED light is a lot. The safe thing to do is start high and move down. I would start that light at 24" and see what happens.

It can be hard to tell they're getting bleached IMO. light green leaves. Also the leaf tips will curl downward, worst at the tops of the stems. Anything bad happening at the tops but not down lower means too close.
 
BiG $m0k3

BiG $m0k3

Active Member
Really appreciate all the advice. Just gotta play around with it and experiment. Gona see what gives the best results.
 
Jmend

Jmend

Member
I started my viparspectra 900w at 30" and I had leaf burn. I moved it up to 40" and it's been fine since! Both plants are growing very fast!
 
hempygrower

hempygrower

Member
I use the cheapo Mars 300w and 600w together,I like to keep the 300w at 22"-24" and the 600w at 24"-26" at the moment, which is a few weeks into veg. Plants seem to love it.

I tried them closer, like 18" and my girls freaked. Never gonna do that again!

I think it depends on chip wattage, manufacturer, par levels, temps, humidity, co2 or not, hydro or soul (haa, I mean soil) etc... like many other people have said here, so many variables to consider.

If you have time and are adventurous, experiment ;) an excellent way to make mistakes to learn from.
 
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