COBs distance from canopy

GreenSanta

GreenSanta

Well-Known Member
Hey guys, looking at a lot of pictures from COBs growers on here, seems like everybody keep their COBs much closer than I do, what is the optimal distance from canopy? one reason for me to keep them so far away is I rarely move the lights, only the plants, and there are a few times where I had a short plant under a light that was hung like 4ft from the tops and plant still grew amazing nugs... I think the sweet spot isnt as close to the canopy as people think, am I right? BTW I am talking about 3590 cxb or vero29, I use both.
 
cdgmoney250

cdgmoney250

Well-Known Member
This is a tough question to answer, because most setup's will be a little different. Depending on the number of chips, the spacing between chips, drive current of the chips, and whether optics are used or not will all play a role in keeping the proper distance from the canopy.

I know most growers don't have a PAR meter, but that is how I measue what the plants are actually receiving at the canopy.

In veg I shoot for 200-400 ppfd, which is about 36" - 48" above the canopy (for my particular light).

In flower I try to stay under 750 ppfd. The light distance from canopy is about 12" - 28" to stay in this sweet spot. And that is with my light fully dimmed down. And I removed my reflectors because I don't have enough heighth in my grow and the intensity was stressing out my plants.
 
BM9AGS

BM9AGS

Well-Known Member
cdgmoney250 said:
This is a tough question to answer, because most setup's will be a little different. Depending on the number of chips, the spacing between chips, drive current of the chips, and whether optics are used or not will all play a role in keeping the proper distance from the canopy.

I know most growers don't have a PAR meter, but that is how I measue what the plants are actually receiving at the canopy.

In veg I shoot for 200-400 ppfd, which is about 36" - 48" above the canopy (for my particular light).

In flower I try to stay under 750 ppfd. The light distance from canopy is about 12" - 28" to stay in this sweet spot. And that is with my light fully dimmed down. And I removed my reflectors because I don't have enough heighth in my grow and the intensity was stressing out my plants.
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What is your setup?
 
BM9AGS

BM9AGS

Well-Known Member
If you're in Colorado Springs could I borrow your par meter? :)

What is the spacing on your VERO 29s?
 
cdgmoney250

cdgmoney250

Well-Known Member
Haha sorry, I'm closer to Boulder. :-)

The spacing on my flower fixture is 11.5" on center. Too close together for 1.4A and limited heighth. I'd have been better off running them at 1.05A and been able to dim them more from that current.
 
BM9AGS

BM9AGS

Well-Known Member
How many grows and strains have you noticed that going over 750 PPFD stresses plants.?

I thought 1200 was the best?!? Clearly I'm wrong......

And to the OP: my distance for 4 cxb 3070 at 50 w each with Chinese reflectors would start bleaching closer than 14" for 1 strain but there were other lights adding so I can't say for certain.
 
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cdgmoney250

cdgmoney250

Well-Known Member
Quite a few grows and many different strains. Im about to finish up my second grow under the LED's with 5 different strains. ALL my plants were stressing when the intensity was higher. I experience the same thing under my HPS. The plants directly under the bulb are always a little more stressed than the others toward the outside of the footprint. Even under the sodiums, the plants stress above 800 ppfd, IME.
 
L

ledfan2

Member
hi
i want build a 25xcxb 3590 3500k cd bin at 0.35 A or 36cxb at ca. 0.25A for a 1,2mx1,2m tent.what do you think how near i can go without lense or other to the canopy at 0.25 or 0.35A.
The Tent have reflecting walls and so i will figure out about the possible near to the canopy and if it ok without lenses or not.
(im not origin english speaker,so excuse my terrible english pls ;-) )
 
CallmeTex

CallmeTex

Well-Known Member
Plants seem to like between 14" and 28" with my 8 cxb at 50 watts each over a 4'x3.5' space. I have gotten too close and bleached a couple plants, but seems like the sweet spot is higher, and allow the lights to blend nice and even.
IMG_1843.JPG
 
J

jay5coat

Well-Known Member
Good to hear I'm not the only one that can not sit the cobs on the plants! My plants like them about 18" to 24" inches away. Any closer and I get some bleaching going on.
 
GroErr

GroErr

Well-Known Member
Been running my 3590's @1.4a at 16-20" above canopy with great results, don't see any benefit (if anything maybe detriments like bleaching) going below 16", plus you lose coverage the closer you go. I don't use meters to test, just look at the results and I'm getting solid buds 30" down, almost no popcorn on pretty well anything I throw under them.
 
Humanrob

Humanrob

Well-Known Member
I'm running cxa/cxb - 3070's @50w/each (between 200w-400w depending on which are turned on) in a 2x4 tent.

I find that one critical part is when they are young, if I'm running clones they need a lot of room from the lights for the first week or two, like 30" - 36". After they get decent roots established I tend to veg between 20" - 26", I usually shoot for around 24". I've run out of room a few times during flower, and its not uncommon for the tallest colas to be around 16" - 18", but less than that and there are usually issues.

I'm also growing in soil. I think that's part of the equation. Closer than 14" I can get burning/bleaching, but even in the 16" - 18" range I'll often have nutrient deficiencies that correct themselves after I raise the lights back up.
 
Olive Drab Green

Olive Drab Green

Well-Known Member
Humanrob said:
I'm running cxa/cxb - 3070's @50w/each (between 200w-400w depending on which are turned on) in a 2x4 tent.

I find that one critical part is when they are young, if I'm running clones they need a lot of room from the lights for the first week or two, like 30" - 36". After they get decent roots established I tend to veg between 20" - 26", I usually shoot for around 24". I've run out of room a few times during flower, and its not uncommon for the tallest colas to be around 16" - 18", but less than that and there are usually issues.

I'm also growing in soil. I think that's part of the equation. Closer than 14" I can get burning/bleaching, but even in the 16" - 18" range I'll often have nutrient deficiencies that correct themselves after I raise the lights back up.
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You want them around 12-16 inches away, but I just had one of mine within 6" without any real issue.
 
Olive Drab Green

Olive Drab Green

Well-Known Member
Humanrob said:
I think the point of this thread is to share what works for you, not to tell others what they should be doing. But I could be wrong. Glad to hear 6" is working for you, that distance would kill my plants.
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..Dude, I wasn't telling him anything, I was giving him my experience to help him decide, and if my lights didn't burn my plants, unless you use HID, neither will yours. I drive my COBs pretty high, higher than most. There should be no reason yours would burn your plants that close.

You're weird, bro. What a dumb response.
 
Danielson999

Danielson999

Well-Known Member
Olive Drab Green said:
..Dude, I wasn't telling him anything
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Olive Drab Green said:
You want them around 12-16 inches away
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Olive Drab Green said:
You're weird, bro. What a dumb response.
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First of all, you were talking to him the whole time. Why suddenly go third-person?
Second, you directly contradicted yourself by saying you weren't telling him anything when you were.
Third, your 2 posts were as weird and dumb as any seen on RIU.

Maybe stop drinking bong water an hour or two before you come here to share your thoughts.
 
Diskokobaja

Diskokobaja

Well-Known Member
I must add i got one chinese blue/red panel and one diy cree 2540 cobs..
I lover it today a little maybe 2-4 inches..And I was convert long first time.. my leds were 50cm -20" apart from plant..
I lower it today to about 40cm -16".
 
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