Light distance at professional facilities

Bubblegum31

Well-Known Member
I have just made the video and after uploading it youtube tell me that I need to verify my account and I cant do that guys..

Any sloution to upload that video, any other website maybe?
 

Bubblegum31

Well-Known Member
yeah and I only grew it for the CBD oil for a friend so I didn't care LOL
Hay RM,is it possible to upload this video on your channel?
My max on youtube is 15 minutes and my video is 17:30 and am not really in the mood to make another one :s!
 

Urbz

Well-Known Member
I ran a 1000w HPS eight inches from my canopy in a 4x4 tent for three weeks in flowering. Never saw plants yellow from the top down before. It was like reverse N deficiency. Haha.
 

SPLFreak808

Well-Known Member
I ran a 1000w HPS eight inches from my canopy in a 4x4 tent for three weeks in flowering. Never saw plants yellow from the top down before. It was like reverse N deficiency. Haha.
I run the same distances when i can get away with it. Some strains no matter how far i start them off actually never stay green at 8"
 

testiclees

Well-Known Member
I had been in the school of closer is better until I read a post where @Greengenes707 was addressing a gardener's light intensity/distance question. Greengenes is master level grower he is also led light designer, gardener, and PLC.

He said this to a dude who has about the same ppfd as me (1290µmols/m^2/sec) and similar environment ;"No matter how high you hang it in the tent with that much light, you should actually notice the best performance with the most clearance as opposed to very close or even at what is considered high normally."

After reading that post I raised my light. Raising it improved my grow. Reading through this thread i think the greengenes was saying the same as the theory that was raised a few posts back i.e. a space that is closed and reflective with high irradiance takes good advantage of the diffused and reflected light. Under this condition low canopy clearance would be counterproductive.

http://biology.mcgill.ca/Phytotron/LightWkshp1994/1.5 Bugbee/Bugbee text.htm
CONCLUSIONS
Differences in radiation quality from the six most common electric lamps have little effect on photosynthetic rate. Radiation quality primarily alters growth because of changes in branching or internode elongation, which change radiation absorption. Growth and yield in wheat appear to be insensitive to radiation quality. Growth and yield in soybeans can be slightly increased under high pressure sodium lamps compared to metal halide lamps, in spite of greatly reduced chlorophyll concentrations under HPS lamps. Daily integrated photosynthetic photon flux (mol m-2 d-1) most directly determines leaf anatomy and growth. Photosynthetic photon flux levels of 800 μmol m-2 s-1 are adequate to simulate field daily-integrated PPF levels for both short and long day plants, but plant canopies can benefit from much higher PPF levels.


https://www.rollitup.org/t/what-is-my-ppfd.896429/#post-12245289
 

517BlckBerry

Well-Known Member
Someone in this thread said you would overdo the heat before the light. LMAO. Guy never saw light bleaching before apparently. I love the responses in here.

I have seen strain differences though. Some (only sativas) I have seen grow right up to the damn glass in the 1000w hood, and NOT be bleached. No bullshit. It was kinda in the corner but still. That plant pulled like 17 ounces I think. So some I do believe can handle just about whatever you throw at it light wise(rare, and dif stages of growth want dif strength). As far as commercial grows, someone said what I was going to already. You get tons of light coverage and crossed light patterns etc..
 

Arcadio

Member
Someone in this thread said you would overdo the heat before the light. LMAO. Guy never saw light bleaching before apparently. I love the responses in here.

I have seen strain differences though. Some (only sativas) I have seen grow right up to the damn glass in the 1000w hood, and NOT be bleached. No bullshit. It was kinda in the corner but still. That plant pulled like 17 ounces I think. So some I do believe can handle just about whatever you throw at it light wise(rare, and dif stages of growth want dif strength). As far as commercial grows, someone said what I was going to already. You get tons of light coverage and crossed light patterns etc..
I said that in my original post. I've found that the runts tend to prefer less light and usually much less nutrients. I don't grow sativas so don't know about them but I;ve grown plenty of hybrids mostly indica dominant. Once when I planted 7 different seeds, 3 Iced Grapefruit by Female Seeds and 4 Purple Haze by G13 Labs. I found that 2 plants were bleaching and 5 were thriving. The light was a 600W MH about 8 inches above the plants by the time they were 10 days old.
So I lowered the height of the pots on those 2 plants to get them away from the light while keeping the other plants nice and close. The 2 plants that I moved away started looking much better after I moved them further from the light but in comparison to the other 5 they were truly runts. And it showed in the end product too, one of them yielded 5 grams!!!!? Can't believe I even let her finish, just too kind I guess. Each plant was in a 7 gallon pot. The other runt yielded like 35 grams. One of the good plants yielded over 8oz by itself!!!! It was a G13 Labs Purple Haze and had delicious and very dense buds.

And these were grown without supplementing co2. I've heard that when you supplement co2 they can use more light than normal. So anyway I've concluded that plants that like low light (and probably low nutes) are gonna grow more slowly and probably gonna end up yielding a little pile of low quality trash. Has been for me at least.

When I've grown outdoors I've found the exact same pattern. The plants that have shown signs of bleaching (rare case) I have taken them out of direct sun and placed them in some shade with my mint and rosemary plants (since I do know about bleaching) and they responded well. But the plants that remain thriving in the direct sunlight are the plants that are gonna be the good yielders with far better quality. And the longer the days the better they grow, they love those 17 hour days with clear skies.

And the thing (that I mention early in thread) about the sun is it provides waaayyy more light than any indoor setup does. The sun can provide over 1000W of LIGHT per square meter. And maintains well above 600W per square meter for great lengths of the day.
Put a 1000W hps in a square meter garden (which you can't do anyway due to heat not light) and you still don't even come close to the sun's light since the 1000W hps does NOT create 1000W of light. It makes about 800W of heat and 200W of light. That fact alone really shows that you'd be hard pressed to even come close to the sun's light intensity. And the fact that the HPS makes 20% light and 80% heat, that's 400% more heat than light, tells me that you would most likely overdo the heat before the light seeing as 400% is a lot and all.

That is in most cases, not for those plants wanna be shaded.
I think it makes perfect sense that the more vigorous plant is going to want more light.

And yeah the 1 time I used a cooled hood I too had the plants grow into the glass with absolutely no probelms. I don't use cooled hoods anymore though because the light distribution sucks and I was using a magnum XXXL. I swapped back to my large adjust a wings for good because the spread is that much better and the open bulb is also better to have for up to 10% more light and also more of the spectrum.
 

Arcadio

Member
But this OTHER video says closer is better. So what can you do, right?

Yeah that is an interesting video and that those are double ended bulbs that he says to keep 6-12 inches away. 6 inches is pretty damn close but I guess with enough AC.
I believe it when he says that when he tried keeping the lights 24-36 inches (as per manufacturer's recommendations) he lost nearly 60 ounces.
 

flowersforfree

Well-Known Member


Ironically putting it higher up (single bulb in tent/closet) can result in better penetration and more uniform light delivery hortizontally and vertically than hanging it as low as possible.

1mm per watt works well for 'small' hps grows as a starting point. Ie. 60 cm (24") for 600watt, little over 3' for thousand. Then lower or raise as needed or desired.
Cool thank you, so I'm right in the ball park.
 

Apical Bud

Well-Known Member
Dear OP:
I share your concern. Everything I have read and everything I have experienced while growing weed tells me more lux is better. The sun gives at least 100,000 lux around here on March sunny days. My outdoor plants cannot be matched by indoor plants, and I don't credit that growth to the compost soil in my garden.
However, recently my grow has been co-opted by more experienced growers who put all our lights 8 feet from the canopy. With 12 1000W hortilux HPS we still get almost 10,000 lux at the canopy. They claim they don't raise their lights, from veg to flower. I have to trust them because of their credentials, but their only seemingly plausible argument is that they trade light intensity at the canopy for distributed intensity from head to toe, so that their side colas will get a lot of light. That argument might hold up because I've gone around their rooms with a lux meter and the lux doesn't change much from top to bottom (because of the linear stacking effect of many bulbs).
However, I believe that their method is simply "good enough" for their purposes. They argued that one of the benefits of their technique is that canopies even out quickly, since no single cola gets more light than any other, and they claim that this disavows the need to top plants, thereby reducing stress. But when I asked them if a lighting system that provided the same even distribution of light but at higher intensity would increase growth they told me it didn't matter. I have already tested plants at 1000 FC, at 500 FC, and at 2000 FC, and I can tell you it matters.
Well, they have 2 months to prove their methods.
I will report back to you on how it goes. But damn, my other buddy grows with 50,000 lux in flower and they will be hard pressed to match his yields.
 
Top