HPS Lighting Penetration--Only facts please

Eagles93

New Member
I recently got into this hobby and it appears to be very easy to fall victim to misinformation. I'd love to put a lot of time into learning everything I can, but that can be difficult when you're unsure what to take as fact or fiction.

I have someone walking me through step by step. He is very knowledgeable and has 10+ years experience, I have seen 50+ of his plants and none of them have a single yellow leaf. He uses a super soil and grows completely organically. He mixes all three types of Fox Farm for the benefits of all the microorganisms in each. He uses the different types of guano for veg/flower. He provided me with a 400 watt as my previous LEDs were only the right spectrum for flowering. He only does organic soil growing as to not sacrifice the taste and smells that can result from using hydro instead.

So basically, he seems to know his shit. Here are where my questions come in.. I've done plenty of research on light/lumens/foot candles. I've looked at the charts, and everything seems to suggest that lumens are severely diminished after 18 inches+ with a 400 watt. Yet he claims and insists that "the 400 watt is plenty of light to light up my 4x8 closet, and that they have all the light they could need"...
Do they? He usually grows under 1000 watts, so obviously that has better penetration. He is completely correct in the fact that even with my light 36+ inches above, my plants are thriving. They also do not have a single yellow leaf, so they appear to be getting everything they could want. So I believe he's correct in the sense that they are getting sufficient light to survive, but let's say according to one of those lumens charts that 20+ inches down you're only at 3000ish lumens. Would my plants be growing almost twice as fast if the lights were close enough for 8,000-10,000 lumens? When I say facts only please, I don't exactly mean that, feel free to post your opinions. But I am looking for some solid evidence that they are growing slower than they potentially could be, or that those foot candle charts are technically false as it applies to plants taking in the light they need. All research I've done suggests that more light = faster growing, higher yield, and more potent bud. Especially in flowering. So pardon the pun, but can anyone shed some light on things?

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astronautrob

Well-Known Member
If I'm not mistaken lumens mean nothing to plants. In my experience you want at least 50 watts per sq ft when you're flowering, so if you have a 4x8 room a 400w is not going to cut it.
 

Gquebed

Well-Known Member
The 400 is just fine for veg. It will work for flower too, but you wont yield as much as you would with more light (in the correct spectrum) and what you do yield will likely be fluffy. If your guy knows his shit then he should know this too...
 

Eagles93

New Member
See here's where I'm confused. I also have a 5 CFL fixture and another single CFL fixture, and I wanted to use those as supplemental lighting for flower. To that he responded, "A 400 watt is sufficient enough for your room and the plants won't even be able to see your CFLs".. So correct me if I'm wrong, but I guess according to you guys, I should position my CFLs an inch or two from bud sites then for added light? And do you think my 400watt would be close enough where it is with the added CFLs? I plan on flowering in two days, and I'm obviously seeking dense, potent buds.
 

zeddd

Well-Known Member
nice looking plants there man healthy as always in supersoil, in the veg stage that you are in a 400 is fine, but if u flower ie flip12/12 with the 400 at that height then they will stretch too much and produce poor bud
 

zeddd

Well-Known Member
can u see that the plant furthest from the bulb have grown more...? this is not good in cannabis it looks nice but u wanna see what happens when u 12/12 them
 

astronautrob

Well-Known Member
Yea even with adding in the CFLs with that 400w you aren't going to achieve the dense bud that you are looking for, potent maybe, but not dense.
 

SPLFreak808

Well-Known Member
I recently got into this hobby and it appears to be very easy to fall victim to misinformation. I'd love to put a lot of time into learning everything I can, but that can be difficult when you're unsure what to take as fact or fiction.

I have someone walking me through step by step. He is very knowledgeable and has 10+ years experience, I have seen 50+ of his plants and none of them have a single yellow leaf. He uses a super soil and grows completely organically. He mixes all three types of Fox Farm for the benefits of all the microorganisms in each. He uses the different types of guano for veg/flower. He provided me with a 400 watt as my previous LEDs were only the right spectrum for flowering. He only does organic soil growing as to not sacrifice the taste and smells that can result from using hydro instead.

So basically, he seems to know his shit. Here are where my questions come in.. I've done plenty of research on light/lumens/foot candles. I've looked at the charts, and everything seems to suggest that lumens are severely diminished after 18 inches+ with a 400 watt. Yet he claims and insists that "the 400 watt is plenty of light to light up my 4x8 closet, and that they have all the light they could need"...
Do they? He usually grows under 1000 watts, so obviously that has better penetration. He is completely correct in the fact that even with my light 36+ inches above, my plants are thriving. They also do not have a single yellow leaf, so they appear to be getting everything they could want. So I believe he's correct in the sense that they are getting sufficient light to survive, but let's say according to one of those lumens charts that 20+ inches down you're only at 3000ish lumens. Would my plants be growing almost twice as fast if the lights were close enough for 8,000-10,000 lumens? When I say facts only please, I don't exactly mean that, feel free to post your opinions. But I am looking for some solid evidence that they are growing slower than they potentially could be, or that those foot candle charts are technically false as it applies to plants taking in the light they need. All research I've done suggests that more light = faster growing, higher yield, and more potent bud. Especially in flowering. So pardon the pun, but can anyone shed some light on things?

View attachment 3580279View attachment 3580280
400w is not nearly enough for dense buds in a 4x8 but it will grow popcorn no doubt. About 1000watts per 4x4 is what i aim for. Any more light and i start to have bleaching issues woth certain strains.
 

jacksthc

Well-Known Member
The chart you found is full of good info but the distance from the hood to the canopy is only down to the heat,
you want the hood really close to the canopy, do the back of the hand test, if you can't hold you hand at the canopy level because its too hot, its too hot for the plants so lift the hood a few inches

a 600w hps would look at lot better in the room
 
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