LED LIGHTS THE ACTUAL TRUTH!

Haha I hear that. Yes for the most part I will take in outside air if it is dry whenever possible. If we get a heat wave I don't mind closing up and running a bit of AC, but this year with all LEDs I am looking forward to see what I can get away with. My central air conditioning is slightly more efficient at removing water than my dehumidifier (1.8L/kWh vs 1.6 L/kW) and it has the bonus of cooling the air rather than heating it. So when I run my AC I consider it dehumidification.

Same here, never have had to deal with PM thank god. But if I let my RH hang at or above 70%, I can start to get bud rot in the biggest colas on the slowest finishers. This year I will make sure to let my circulation fans run more during lights out and I will add a circulation fan to the trimming room.

When it comes down to it my electric bill is no problem we have a pretty decent rate, but I consider all this preparation for the future. I expect a rising trend in electric prices over time. We are lucky in the US so far but many other countries are paying much more. Also I want to reduce my energy consumption as much as possible out of respect/concern for our ecosystem. On average coal power plants are only 33% efficient and another 8-10% is lost in transmission. So when you reduce your power usage, that reduction is multiplied by 4.

HolyGhost23 said:

i know a chinese nock off is not going perform as well as an american made CREE cob style light but i believe the idea is the same... hell when i was a lad.. we used mercury vapour lights.. and those put out about 6-8000 lumens a piece.. they did wonders when chronic was the king strain.. so yeah the cheap 50x1w might not be the best of the LED world. but i think a grow can still be done..

also you have no idea what im planning for my grow journal.. ive been on this fourm for years and what im planning for my first real grow journal is going to be an idea ive wanted to put out there for a while.. so don't go assuming im all words..

on that note is there any way of testing thc content of a plant in your own home.. and if not is there a lab that will take samples?

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Yes, there is a way of testing in your own home. I'm doing it right now.

Sativied said:

Yeah it does suck, especially during the fall you can actually notice the decreased quality in coffeeshops, sometimes referred to as 'wet-basement-weed' (sounds better in dutch). You say the HPS is not 'going' to help, yet the reality is it has been successfully doing so for many decades, and again in combination with a tried and proven design in which the HPS+exhaust+space balance is key to creating a workeable environment without having to spend a lot on airco and climate control.

It is high humidity combined with cold that causes rot and mold and some of the abundant airborne spores and plant diseases to thrive. The HPS warmth/heat helps prevent problems that arise from not being able to suck in air that's far less humid than what the plants create by transpiration during lights on. HPS causes more transpiration than LED, of course, the better temp alone will do that. Although there is a point of no return, generally more transpiration isn't a bad thing unless it becomes too much, on the contrary. Also warm air can retain humid more easily, a good exhaust takes care of that increase. Lowering the exhaust output, as would be necessary to prevent it from getting too cold, is only going to make matters worse.

Indeed, but at least with HPS and the inherit high exhaust output it lowers and warms up significantly during lights on. When replacing that HPS with LED and lowering the exhaust it will remain closer to the 'true humidity level' which is a combination of the environment the plants create AND the air sucked in.


So do some large greenhouses here, stacking many layers of clones and tissue culture and using LED, in which case it is specifically meant to replace T5 and T8 and not HPS SON-T. Stacking multiple grows that normally use HPS isn't going to work in our rooms, basements, tents, and attics so I cannot really consider that a valid argument.

That's good enough to match HPS in gpw but again you underestimate the surface area factor. Someone with a 4x5' space here is going to use a 600 watt HPS +10% boast and get 20+ oz instead. Or use a 1000watter with dimmer to save some electricity the first weeks before the canopy fully fills the room and get 30+ oz from it. Saving 100W would effectively mean a pretty huge loss for a typical 'breadgrower' here (based on 6 cycles a year that would be roughly $4500. Not even mentioning the additional investment and climate control costs as I outlined in previous posts. When you actually need to pay bills and put food on the table by growing mj 'efficiency' takes on a more realistic, and practical form.

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Good points grower........just remember that a 1000w hps it's at it's most efficient running at full blast. Dimming is not recommended by most manufacturers. Neither is cooling the bulb directly

As with all HID bulbs dimming lowers efficiency and creates a spectral shift

1000w hps bulb dimmed to 600w IS NOT equal too 600w hps bulb running @ 600w when it comes to efficiency and spectral distribution

Growershouse has a nice little video of the spectral shift and efficiency of dimming a HPS 1000w bulb. There are changes in both, but not drastic. Check it out..........http://growershouse.com/blog/1000w-hortilux-hps-bulb-spectrum-intensity-as-wattage-changes/

Red1966 said:

Growershouse has a nice little video of the spectral shift and efficiency of dimming a HPS 1000w bulb. There are changes in both, but not drastic. Check it out..........http://growershouse.com/blog/1000w-hortilux-hps-bulb-spectrum-intensity-as-wattage-changes/

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you beat me to it

What do I win?

Red1966 said:

What do I win?

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this cap of knowledge

I'll treasure it always.

Red1966 said:

Growershouse has a nice little video of the spectral shift and efficiency of dimming a HPS 1000w bulb. There are changes in both, but not drastic. Check it out..........http://growershouse.com/blog/1000w-hortilux-hps-bulb-spectrum-intensity-as-wattage-changes/

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thanks, really surprised at how small the diff. is........ I guess these new hortis are digital complaint

hyroot said:

this cap of knowledge

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Red1966 said:

I'll treasure it always.

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lol..............

spazatak said:

why does the hans panel perform so well?

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good question!

SupraSPL said:

Sure you could stack flowering shelves with LED, whats to stop it?

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In my case a concrete ceiling and a hydro setup. You're right though, it 'could' actually work in plenty of situations (high room or low plants and a less high hydro setup in my case).

SupraSPL said:

Regarding my yield, you have to take into consideration that yield is not my first priority in selection, it is quality. Out of 120 females so far, I have never found a large yielder that had enough funk to make the cut. Also consider, when I was using 600 HPS my very best yield was .56 gr/W. As the bulbs aged I was getting .3 -.4 gr/W consistently. Using the same space, same soil, same bucket and the same rotation of cuttings LED gets me almost 1 gr/W.

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Oh, I can see now how you can double/triple your gpw if your starting point is only half a gram or less per watt under HPS. Like you I care much more about quality than quantity (all for spouse and me). I usually get 0.8-0.9 gpw without really making a quantity effort. Just finished a 0.8gpw (600watt on 4x4', 6 plants) with clones I took from plants for their quality and not for being the best yielders. 450ppm-run, no boosters/stims/hardeners or whatever.

Point is, if you aim for quality then quantity will follow eventually. I will go as far - and mean no offense - as saying that if you only get .3-.4 gpw from a 600watt the quality probably wasn't all that good either - something went wrong. With HPS a grower should aim for 1 gpw, be happy already with 0.75gpw and look for major improvements if it's 0.5gpw. What it comes down to is that you are comparing your failed HPS grows to your successful LED grows. Clearly it shows LED is the better match for you subjectively but it says little to nothing about LED vs HPS objectively. I'm all quality-over-quantity but that doesn't mean quantity automatically comes with the cost of less quality. It also doesn't mean you should accept 5% quality gain at a cost of 50% yield gain. There's a healthy balance, and you can have both quantity and quality with HPS, plug-and-play.

SupraSPL said:

So if your guys are getting 30 oz, I expect they will continue to get their 30oz but using only half the wattage and less electricity on AC and ventilation.

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Just doesn't sound realistic, and if it were we'd actually be seeing many of such grows rather than speculating about it. Gavita is a very popular manufacturer here, and their high-end HPS setups aren't that much cheaper than a LED setup (for example, the new line: http://www.greensell.nl/c-2488394/gavita-pro-line-e-serie/ with remote control p&p) so the initial investment isn't that much of any issue for the larger growers. And again the advantages are clear, and the increased stealth alone would make it an easy choice if your expectations of getting the same yields with half the power were realistic.

SupraSPL said:

Anyway, I am just trying to show the potential for improvement that exists out there,

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Well, nice try, but no cigar from me

As for the comments in the other led thread, I don't know what 2gpw looks like either. Seems the max I could physically fit (bud to bud and still some space in between) combined with long tall buds is roughly 1.5gpw and then (with the shitty weather here) that's really asking for problems. However, as I mentioned before LED manufacturers and fans often turn the negative of the narrow light direction of LED into a positive, or at the least a negative for HPS. With a good hood and wall reflection that become almost a non-issue in a small setup, but in a larger setup with multiple HPS bulbs there's the advantage of overlap, which with proper folded/setup spreading hoods has a positive effect on the gpw in the room that adds up per light. For example, 1.5gpw is a lot easier to achieve with 3x600watt in a row or 2x2 600 lights in a square setup than it is with 1x600watt. I was really being modest with that 30 oz (0.8gpw in that example) if applied to a setup with more than a couple of bulbs.

As for the comments about less efficiency when you dim HPS (which is basically per w and the context was the 4x5' example space, how that could be more optimal filled with hps), even if it were significant, running 800watt at 10% decreased efficiency is still more "efficient" for me in a way that actually matters, i.e. rather then using a 1000watt to light up the floor before the canopy closes and fills the space. Merely an example to compare to that 480w led at 1gpw. I use a separate 400 watt set the first few weeks and 600watt set for actual flowering/budding to reduce the electricity bill, improving the gpw similar to how LED theoretically does, i.e. by lowering electricity usage and not actually increasing total weight one can pull from a surface (on the contrary).

One perk to using LED's over HID, cobs especially, is that you can dim them with no effects to or in fact inverse effects with increased efficiency. It's also easier to setup different 'modes' by installing switches on your LED's. Like Gaius did with his Battlestar Ganjatica build and turn off individual emitters entirely. So less power is used with no effect to efficiency.

I like the preliminary results I've seen so far with DIY COB LED panels. It's going to be even more interesting when cree 3070's and 3590's become more available. Bridgelux recently dropped the price of the vero line, which makes me wonder what they've got up their sleeve.

my next grow might be a few cree 3070's running at 1.9 amps..

Sativied said:

What it comes down to is that you are comparing your failed HPS grows to your successful LED grows. Clearly it shows LED is the better match for you subjectively but it says little to nothing about LED vs HPS objectively.

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Although my setup is very experimental in a lot of ways, I dont consider my HPS grows a failure. But if we assume there is something terribly wrong with my system, how would I suddenly start having success when switching to LED? I got .3-.4gr/W consistently for several years with overlapping HPS (admittedly, some were aged bulbs). When I scrapped the first HPS and started to replace with LED it rose to .57gr/W then .67gr/W and now with HPS completely phased out my first LED result is about .85-.9gr/W (will get this number in a few days). I somehow doubt that the explanation is I turned into a better grower and I certainly was not trying to sabotage the HPS grows.

But you are correct, LED does suit my growing style and space. For one thing I was not keeping up on HPS bulb replacement, I ran the HPS bare and I tried to keep canopy temps near 80 without AC.

Sativied said:

I'm all quality-over-quantity but that doesn't mean quantity automatically comes with the cost of less quality. It also doesn't mean you should accept 5% quality gain at a cost of 50% yield gain. There's a healthy balance, and you can have both quantity and quality with HPS, plug-and-play.

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I agree with recognizing the law of diminishing returns, but I do not agree that the big yielders are only 5% less quality than my best keepers. If that were true there would be nothing but bomb-fire-dank everywhere, all the time. It is a night and day difference. One of my favorite pastimes is to explore genetics. So far I have had the pleasure to test ~120 individual females from respected breeders (mostly under HPS) and there are about 10 that I consider keepers. They are not horrible yielders otherwise I would not consider them keepers. They sparkle with bright trichs and will turn any house into a skunk bomb for hours if anyone dares to crack open a jar. I just do not get that kind of quality with the big yielders. They tend to foxtail and the weed either has no smell or smells farmy. I have plenty of friends that grow under HPS and have swapped varieties and compared results. They select for yield with a lesser interest in quality. I select for quality with a lesser interest in yield and we all achieve our goals. I am perfectly happy with .9gr/W if it is super dank, although I do expect better numbers when I do make some changes to my system.

Sativied said:

Just doesn't sound realistic, and if it were we'd actually be seeing many of such grows rather than speculating about it.

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The LEDs I am advocating are newly available so you won't see many grows just yet. I expect lots of people who have their hands on the new COBs will outyield me. It does not require a leap of faith, for the first time these LEDs are much more efficient than HPS and they emit in a cone pattern. That puts more photons in the canopy using less power, therefore an improvement in grams/W.

Sativied said:

Gavita is a very popular manufacturer here, and their high-end HPS setups aren't that much cheaper than a LED setup... so the initial investment isn't that much of any issue for the larger growers. And again the advantages are clear, and the increased stealth alone would make it an easy choice if your expectations of getting the same yields with half the power were realistic.

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No matter how fancy they get, HID cannot achieve the efficiency levels of the best COB LEDs and no matter how fancy the reflector, HID cannot deliver the photons to the canopy as efficiently as LED, so if efficiency is your goal and the price is the same, why bother with HID?

As far as plant efficany in making THC. You have to use common sense and also remember the laws of nature.. if your going to try to get 1lb off a single plant its going to have more vegitagive matter compared to trichome coverage. As for % values of THC. It comes down to this. A plant can only focus so much energy on producing THC before it compromises producing essential nutrients to keep it alive.. I think monsanto got a cannabis plant to max out at 33.25% THC before it could no longer support itself. Nature is about balance if you make that much THC the plant will not be geneticly focused on making vegetative matter.. you need to lose one to gain another... on that note the beat weed I ever smoked looked like tiny little green raisans that looked like they got rolled in a pile of meth... it was tested at 27% THC.. the entire plant maybe got an oz dry..

I could keep reading this excange of arguments for ever

Thank you Supra, others and Sativied. As I am usually more interested in leds I think these insights into "professional" horticulture are a very good and interesting read. Because I bet many people wondered "if led is that good, why does $$$$$$$ industry still use hps."
Of course any new Information I gain about led is like honey, and there is plenty of this in here.

HolyGhost23 said:

As far as plant efficany in making THC. You have to use common sense and also remember the laws of nature.. if your going to try to get 1lb off a single plant its going to have more vegitagive matter compared to trichome coverage. As for % values of THC. It comes down to this. A plant can only focus so much energy on producing THC before it compromises producing essential nutrients to keep it alive.. I think monsanto got a cannabis plant to max out at 33.25% THC before it could no longer support itself. Nature is about balance if you make that much THC the plant will not be geneticly focused on making vegetative matter.. you need to lose one to gain another... on that note the beat weed I ever smoked looked like tiny little green raisans that looked like they got rolled in a pile of meth... it was tested at 27% THC.. the entire plant maybe got an oz dry..

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a
my quantum kush (day 16 from seed) is supposed to be a huge yielder and 30% thc and high in cbn's and thcv , thca ... i don't think having high amounts of thc compromises anything... its all about genetics. you have poor genetics then that may be the case. high potency does not at all mean small buds... all my strains are 22% + thc and big cola producers

Hypothesis:
at same umol Levels of hps and led and constant RT (room temperature), hps delivers additional IR beams heat resulting in increased leaf temperature.
At very high umol Levels leaf temperature becomes a limiting factor (enzymatic and chemical reactions), besides CO2 Levels.
At same umols and constant RT: HPS outyields (g/umol) LED due to an increase in enzymatic activity

Getting the same increased leaf temperature for LED by inceasing room temperature:
Increase in Air temperature leads to a decrease in relative humudity (rh). A decrease in rh leads to an increase in vapour pressure deficit. Increased VPD leads to an increase of transpiration. An increase of Transpiration leads to an increased cooling effect, thereby cooling the leaf to a temperature below the targeted leaf temperature.

What do you say?

lax123 said:

Hypothesis:
at same umol Levels of hps and led and constant RT (room temperature), hps delivers additional IR beams heat resulting in increased leaf temperature.
At very high umol Levels leaf temperature becomes a limiting factor (enzymatic and chemical reactions), besides CO2 Levels.
At same umols and constant RT: HPS outyields (g/umol) LED due to an increase in enzymatic activity

Getting the same increased leaf temperature for LED by inceasing room temperature:
Increase in Air temperature leads to a decrease in relative humudity (rh). A decrease in rh leads to an increase in vapour pressure deficit. Increased VPD leads to an increase of transpiration. An increase of Transpiration leads to an increased cooling effect, thereby cooling the leaf to a temperature below the targeted leaf temperature.

What do you say?

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Can you explain /analyse why this will happen ?


I had the impression that exactly the opposite happens .
I've always thought that lower temps translate to lower Rel.humidity ...

Below zero Celcious ,air is totally dry . 0% rel.hum.
Water vapour has solidify into ice particles and dropped ,due to gravity ...


Less energy given,lower the energy state of matter .
If you apply heat ,water molecules start to 'move' faster .
At one point they're 'escaping' the 'matrix' of the liquid state.
They become Vapour.Gas state.

Subtract energy ,and motion becomes less .
Water molecules form a 'still' crystal matrix.
Ice .Solid state ..

Explain please ,how-contrary to thermodynamic laws-you will increase heat and the rel. humidity will
decrease ...

While evaporation of all water molecules around ,will be increasing,how on Earth rel.humidity will decrease ?
.....

stardustsailor said:

Can you explain /analyse why this will happen ?


I had the impression that exactly the opposite happens .
I've always thought that lower temps translate to lower Rel.humidity ...

Below zero Celcious ,air is totally dry . 0% rel.hum.
Water vapour has solidify into ice particles and dropped ,due to gravity ...


Less energy given,lower the energy state of matter .
If you apply heat ,water molecules start to 'move' faster .
At one point they're 'escaping' the 'matrix' of the liquid state.
They become Vapour.Gas state.

Subtract energy ,and motion becomes less .
Water molecules form a 'still' crystal matrix.
Ice .Solid state ..

Explain please ,how-contrary to thermodynamic laws-you will increase heat and the rel. humidity will
decrease ...

While evaporation of all water molecules around ,will be increasing,how on Earth rel.humidity will decrease ?
.....

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You are correct SDS..............most damage done to perennials isn't just the cold, it's the low RH drawing moisture out of the leaves that causes severe necrosis.

big reason citrus growers spray water on the fruit before frost (RH retension)