Light distance at professional facilities

Arcadio

Member
Hey people, I have done a ton of reading and general research when it comes to all aspects of indoor growing and I'm happy with most of my knowledge and beliefs but I have recently come across a contradiction. Here it is,

I have always believed that it's best to keep your lights (MH and/or HPS) as close as possible (without heat stressing your plants). I have found that with good airflow, between canopy and bulb, as well as a fan pointed at the bulb itself allows the lights to be very close to the canopy, about 8-10 inches for a 600W MH and the leaf temp stays in perfect range around 78F.
I have read in many places that this is ideal since having the lights closer to the plants means more intensity and deeper penetration. Given that the plants are at ideal temps this should be the best way to go unless the high light intensity is too much hence not optimal. Most setups that I've seen try to keep the lights as close as possible and they seem to do very well. I do understand that as plants get bigger you need to sacrifice intensity for coverage but let's just consider the stages where you can keep your light/s very close without worrying about coverage, i.e. early/mid veg.

Here's the thing though, all the professional grow facilities that I have seen on videos that are in big warehouses with hundreds of plants, always keep the lights ridiculously far away from the plants, like 3 or 4 feet. And they do very very well. Why do they keep the lights so far away. I know that there are heaps of lights in these setups. Is this the reason why? So that the lights all create more coverage and they all sort of share the lights.

So in a small setup with only 1 or 2 lights, should you keep the lights as close as possible or keep a good distance? I saw a video on youtube on the "Grow Boss" channel and he shows you a small single light setup (400W MH in veg) with the light not even close and he says its way too close and its harming the plants and making them "miniaturize", then he moves it up to about 2 feet and says this will solve the problem. Here's the video. Start at 4:20 and just watch for about a minute to see what I mean.


This really made me wonder but I don't believe he is right. I have done a few grows in the past using 600W MH for veg and I kept the light nice and close like 8-10 inches with good air flow as I said earlier. I had very healthy fast growing bushy plants (nothing like the twig weeds in that video lmfao).
I believe that the plants were able to utilize the high light intensity. Seeing this guy raise a 400W MH that far up trips me out, and he's saying that this is the key to making those shitty plants less shitty. It really makes me think that although he may be wrong, perhaps I am also wrong and the right answer is somewhere in between.

My philosophy is that our beloved plants are able to soak up massive amounts of light and the more you can give them (within reason) without heat stressing them the better. Their philosophy is that HID lighting is ultra powerful so you need to tread with caution and keep the light a mile away.

I've used a light meter to measure the sun on the middle of a clear summer day and it read over 120 000 lux. I used the same meter to measure a 600W MH from 8 inches and it was well under 100 000. Furthermore the sun gives the same light intensity to the top of a 300 ft tree as it does to the ground. So that is one very powerful light they have evolved with. I know that indoor lights are kept on for much longer and they don't vary with weather but still the sun is a fair bit more powerful than even a 1000W HID at 12 inches in terms of intensity, penetration and bandwidth and it contains much more high energy radiation such as UVB which is more harmful for living organisms.

What do you guys think? I know that the professional warehouse grows have heaps of lights. Is this what justifies the lights being raised so high for them?
And what about small setups what are your thoughts on that? Is it best to keep the lights as close as possible to get better penetration and higher intensity?

Do you agree with the "Grow Boss" that its best to keep your light waaayyyyy above your plant, 2ft for a 400W MH and who knows how far up he would raise a 600W MH. Would you really keep your light that far away throughout veg? Wouldn't you get a lot more stretch and less vigorous growth?
In my opinion, that light was too far away to begin with. Even if it was a 600W MH, (much hotter and brighter than a 400W MH) I would be moving that light down a few inches to try and get light intensity up closer to what the sun can give. And what about if you're supplementing CO2, can't they use even more light than what the sun can provide?

I don't know but it's my gut feeling that a single 400W light at 2 feet isn't the way I'd want to be growing if I were a plant. I think I'd be wishing the light was closer.
 
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BobCajun

Well-Known Member
Hey people, I have done a ton of reading and general research when it comes to all aspects of indoor growing and I'm happy with most of my knowledge and beliefs but I have recently come across a contradiction. Here it is,

I have always believed that it's best to keep your lights (MH and/or HPS) as close as possible (without heat stressing your plants). I have found that with good airflow, between canopy and bulb, as well as a fan pointed at the bulb itself allows the lights to be very close to the canopy, about 8-10 inches for a 600W MH and the leaf temp stays in perfect range around 78F.
I have read in many places that this is ideal since having the lights closer to the plants means more intensity and deeper penetration. Given that the plants are at ideal temps this should be the best way to go unless the high light intensity is too much hence not optimal. Most setups that I've seen try to keep the lights as close as possible and they seem to do very well. I do understand that as plants get bigger you need to sacrifice intensity for coverage but let's just consider the stages where you can keep your light/s very close without worrying about coverage, i.e. early/mid veg.

Here's the thing though, all the professional grow facilities that I have seen on videos that are in big warehouses with hundreds of plants, always keep the lights ridiculously far away from the plants, like 3 or 4 feet. And they do very very well. Why do they keep the lights so far away. I know that there are heaps of lights in these setups. Is this the reason why? So that the lights all create more coverage and they all sort of share the lights.

So in a small setup with only 1 or 2 lights, should you keep the lights as close as possible or keep a good distance? I saw a video on youtube on the "Grow Boss" channel and he shows you a small single light setup (400W MH in veg) with the light not even close and he says its way too close and its harming the plants and making them "miniaturize", then he moves it up to about 2 feet and says this will solve the problem. Here's the video. Start at 4:20 and just watch for about a minute to see what I mean.


This really made me wonder but I don't believe he is right. I have done a few grows in the past using 600W MH for veg and I kept the light nice and close like 8-10 inches with good air flow as I said earlier. I had very healthy fast growing bushy plants (nothing like the twig weeds in that video lmfao).
I believe that the plants were able to utilize the high light intensity. Seeing this guy raise a 400W MH that far up trips me out, and he's saying that this is the key to making those shitty plants less shitty. It really makes me think that although he may be wrong, perhaps I am also wrong and the right answer is somewhere in between.

My philosophy is that our beloved plants are able to soak up massive amounts of light and the more you can give them (within reason) without heat stressing them the better. Their philosophy is that HID lighting is ultra powerful so you need to tread with caution and keep the light a mile away.

I've used a light meter to measure the sun on the middle of a clear summer day and it read over 120 000 lux. I used the same meter to measure a 600W MH from 8 inches and it was well under 100 000. Furthermore the sun gives the same light intensity to the top of a 300 ft tree as it does to the ground. So that is one very powerful light they have evolved with. I know that indoor lights are kept on for much longer and they don't vary with weather but still the sun is a fair bit more powerful than even a 1000W HID at 12 inches in terms of intensity, penetration and bandwidth and it contains much more high energy radiation such as UVB which is more harmful for living organisms.

What do you guys think? I know that the professional warehouse grows have heaps of lights. Is this what justifies the lights being raised so high for them?
And what about small setups what are your thoughts on that? Is it best to keep the lights as close as possible to get better penetration and higher intensity?

Do you agree with the "Grow Boss" that its best to keep your light waaayyyyy above your plant, 2ft for a 400W MH and who knows how far up he would raise a 600W MH. Would you really keep your light that far away throughout veg? Wouldn't you get a lot more stretch and less vigorous growth?
In my opinion, that light was too far away to begin with. Even if it was a 600W MH, (much hotter and brighter than a 400W MH) I would be moving that light down a few inches to try and get light intensity up closer to what the sun can give. And what about if you're supplementing CO2, can't they use even more light than what the sun can provide?

I don't know but it's my gut feeling that a single 400W light at 2 feet isn't the way I'd want to be growing if I were a plant. I think I'd be wishing the light was closer.
But this OTHER video says closer is better. So what can you do, right?

 

RM3

Well-Known Member
For years my pet peeve has been growers crammin light up the plants ass without understanding that light is simply just one of the elements that needs to be dialed in.

Folks are always amazed at what I accomplish using T5's to flower and I keep em 2 feet off the canopy. The reason you see commercial lights so high up is they understand this.

This bud is is the the bottom branch of a plant that is over 3 feet away from the nearest T5 bulb 8)
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T_SAM_2888.JPG T_SAM_2865.JPG
 

BobCajun

Well-Known Member
Here is what the top looked like 8)
Ever try using pure red and blue T5s? I don't know what's available but I found this. I would think it would be more efficient to use 3 red/ 1 blue than the various shades of white. Maybe not, but in theory. Or maybe just adding a few reds to the whites.
 
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RM3

Well-Known Member
Ever try using pure red and blue T5s? I don't know what's available but I found this little red one. I would think it would be more efficient to use 3 red/ 1 blue than the various shades of white. Maybe not, but in theory.
I have tested many bulbs and I mix em to give a complete spectrum I even have 3 UV bulbs in there. I like more deep blue than red because it increases tric production so I run 9 deep blue with 6 reds + the 3 UV's makes 18 bulbs which = roughly 1000 watts
 

BobCajun

Well-Known Member
I have tested many bulbs and I mix em to give a complete spectrum I even have 3 UV bulbs in there. I like more deep blue than red because it increases tric production so I run 9 deep blue with 6 reds + the 3 UV's makes 18 bulbs which = roughly 1000 watts
Oh, I thought it was like warm whites and daylights. Interesting that blue makes more trics. So did you find that pure red and blue gave better yields than warm whites, for instance?
 

jafro daweedhound

Well-Known Member
I don't know but it's my gut feeling that a single 400W light at 2 feet isn't the way I'd want to be growing if I were a plant. I think I'd be wishing the light was closer.[/QUOTE]

I have found that some strains will taste bitter if too close to the light while lower branches on the same pant taste the way they should.
 

BobCajun

Well-Known Member
I have found that some strains will taste bitter if too close to the light while lower branches on the same pant taste the way they should.
Yeah buds too close to lights get very dry and woody. If there was a way to put a double layered glass sheet over the plants and pump water through the space between them, it would absorb all the IR. I guess a water cooled lamp would never pass safety regs though.
 

Bubblegum31

Well-Known Member
For years my pet peeve has been growers crammin light up the plants ass without understanding that light is simply just one of the elements that needs to be dialed in.

Folks are always amazed at what I accomplish using T5's to flower and I keep em 2 feet off the canopy. The reason you see commercial lights so high up is they understand this.

This bud is is the the bottom branch of a plant that is over 3 feet away from the nearest T5 bulb 8)
.
View attachment 3646987 View attachment 3646988
Any branch will still give buds even if its not getting direct light, but is it gonna be the same like the upper buds؟? Offcourse NOT!

Warehouses using the manfacture recommendations, they know there shit! They made it, they tested it and they know what is the best distance from the canobay.

Check gavita website they till you the best distance for each structure accoeding to thier tests.

Long short stoy, I wouldnt liesten to this maffo look how his plants are stretchy and looking shit.

I doubt that he even get a good yield!

I would let my lights get best of both. as much possible distance and coverge.

If am able to have 1000w 1 inch above my plants ill simply do it if I can have the whole plant and bud locations exposed to light!

When I bend a stem or remove a fan leaves that are blocking the light on some tops, those tops grow big in NO time!

I wouldnt liesten to this guy and if I got a big commercial grow 10k plus ill take the manfacture advise for sure in mind!
 

RM3

Well-Known Member
Very nice system, but your average grower ain't going to go there, setting up a system like yours, relying on t5's.
I have used them for years, and those you can literally put on top of your plants (not VHO), and get good results.
Totally understand that, but my point is, if I can do this with T5's imagine what you could do if only you learned to dial in all the elements not just light ???
 

Alexander Supertramp

Well-Known Member
Any branch will still give buds even if its not getting direct light, but is it gonna be the same like the upper buds؟? Offcourse NOT!

Warehouses using the manfacture recommendations, they know there shit! They made it, they tested it and they know what is the best distance from the canobay.

Check gavita website they till you the best distance for each structure accoeding to thier tests.

Long short stoy, I wouldnt liesten to this maffo look how his plants are stretchy and looking shit.

I doubt that he even get a good yield!

I would let my lights get best of both. as much possible distance and coverge.

If am able to have 1000w 1 inch above my plants ill simply do it if I can have the whole plant and bud locations exposed to light!

When I bend a stem or remove a fan leaves that are blocking the light on some tops, those tops grow big in NO time!

I wouldnt liesten to this guy and if I got a big commercial grow 10k plus ill take the manfacture advise for sure in mind!
Dude Riddle knows more about cannabis than most. His shit is some serious fire. Most of you following cannabis forum myth would do yourselves a favor by listening to him.
 
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