Question for all LED users out there

The_Enthusiast said:

Than great, there is a break even point. I just like to hear from people that are/were growing under HPS and switched to LED using same technique and strain.
I just hate so much misinformation in this business and false promises.

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If your area is properly lit you won't see an increase in yield, plants can only absorb so much light and the light source isn't the most important thing as long as you are getting around 600-900 PPFD. These people that said they doubled or tripled their yield must have been terrible growing with HID lights, if i tripled my yield i'd be getting 3 grams per watt i'm pretty sure that's impossible. There is a whole hell of a lot of opinion on this section of the forum, not much to back those opinions up besides bashing and name calling, not much fact or science . You won't see many side by side grow logs of LEDs vs HID lights because usually they don't work out well for the guy who spent 10x more to cover the same area and yields slightly less. Just watch greengene's 1000w hps vs AT600 grow log, he confined his 1000w HPS to a 4x4 to give the AT600 the advantage (a 1000w hps easily covers a 5x5 with the proper reflector) and still yielded a few ounces less with the LEDs than the HPS. If i were looking to get a new light source i'd look into CMH lights, LEDs are just too costly, for what they are, they have zero UV, zero far red, HID lights are still superior.

@ttystikk, @CobKits This guys back^ Its not about doubling the yield, its about hitting the same or better numbers with less light and way less heat. Theres alot you're not taking into account Mr Yodaweed.

MeGaKiLlErMaN said:

@ttystikk, @CobKits This guys back^ Its not about doubling the yield, its about hitting the same or better numbers with less light and way less heat. Theres alot you're not taking into account Mr Yodaweed.

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If you don't yield more , what's the point? Saving 30$ a month in electric? That's like 2 grams of weed. Some people need the heat, it was -10F already this year where i live, my grow room is 68F with all my HPS lights running. Proper ventilation and heat exchange will do wonders for any grow.

Yodaweed said:

If your area is properly lit you won't see an increase in yield, plants can only absorb so much light and the light source isn't the most important thing as long as you are getting around 600-900 PPFD. These people that said they doubled or tripled their yield must have been terrible growing with HID lights, if i tripled my yield i'd be getting 3 grams per watt i'm pretty sure that's impossible. There is a whole hell of a lot of opinion on this section of the forum, not much to back those opinions up besides bashing and name calling, not much fact or science . You won't see many side by side grow logs of LEDs vs HID lights because usually they don't work out well for the guy who spent 10x more to cover the same area and yields slightly less. Just watch greengene's 1000w hps vs AT600 grow log, he confined his 1000w HPS to a 4x4 to give the AT600 the advantage (a 1000w hps easily covers a 5x5 with the proper reflector) and still yielded a few ounces less with the LEDs than the HPS. If i were looking to get a new light source i'd look into CMH lights, LEDs are just too costly, for what they are, they have zero UV, zero far red, HID lights are still superior.

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Most HID have so little UV it is a wash. If you put glass between the bulb and plants then no UV at all. Also yes 90 CRI has 730 nm far red and actually had a really good ratio too.

Stephenj37826 said:

Most HID have so little UV it is a wash. If you put glass between the bulb and plants then no UV at all. Also yes 90 CRI has 730 nm far red and actually had a really good ratio too.

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That's simply wrong , here's the data to backup my claims , i'd like you to provide the same and stop injecting your opinion.


Scroll to 5 mins 50 seconds for UV readings.


And also for 600w HID lights

http://www.eyehortilux.com/products/specific/600w-Hortilux-Blue

Yodaweed said:

If you don't yield more , what's the point? Saving 30$ a month in electric? That's like 2 grams of weed. Some people need the heat, it was -10F already this year where i live, my grow room is 68F with all my HPS lights running. Proper ventilation and heat exchange will do wonders for any grow.

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Yes it's true some people don't have problems with the heat in ther grow environment and the electrical savings can be small. In some places though the electrical savings can be huge. Still have to consider bulb changes in that equation as they aren't free either. In places where AC is a must that initial installation cost can be lower as well as the less energy needed to cool the area because of (A) less overall wattage/heat and (B) Overall higher temps are good for LED vs HPS.

Yodaweed said:

That's simply wrong , here's the data to backup my claims , i'd like you to provide the same and stop injecting your opinion.

Scroll to 5 mins 50 seconds for UV readings.


And also for 600w HID lights

http://www.eyehortilux.com/products/specific/600w-Hortilux-Blue

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Do you flower with Eye Blue Metal Halide or CMH? Also most of the bulbs that have UV only have a single jacket(not rated for open reflector use).

Look it up it's called ANSI rating.

Stephenj37826 said:

Do you flower with Eye Blue Metal Halide or CMH? Also most of the bulbs that have UV only have a single jacket(not rated for open reflector use).

Look it up it's called ANSI rating.

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Stop bro, those lights tested were double jacketed, you just putting out wrong statements and have no proof or facts to backup any of your baseless conjecture.

Yodaweed said:

Stop bro, those lights tested were double jacketed, you just putting out wrong statements and have no proof or facts to backup any of your baseless conjecture.

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Sucks don't it..... Maybe you should follow your own advice sometime.

Stephenj37826 said:

Do you flower with Eye Blue Metal Halide or CMH? Also most of the bulbs that have UV only have a single jacket(not rated for open reflector use).

Look it up it's called ANSI rating.

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UVB also is the only proven spectrum that actually increases trichomes. It's wavelength is 290-320 nm..... I don't see much of any in those bulbs . Remove the inner jacket and see. This is not conjecture this is fact bud.

And HPS has zero.... Straight out of Theo's mouth.

Stephenj37826 said:

UVB also is the only proven spectrum that actually increases trichomes. It's wavelength is 290-320 nm..... I don't see much of any in those bulbs . Remove the inner jacket and see. This is not conjecture this is fact bud.

And HPS has zero.... Straight out of Theo's mouth.

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Exactly^ and that's what I push, facts is the UV isn't enough to make a difference at about 5W of UVA/UVB so at best you get around half of that from a DE HPS. Over the whole growing area.

That's like saying my car gets an extra .05 mile per gallon... It's not a big difference and really doesn't effect the performance of the car, it's not even what people look at unless they want to improve trichs, in this case they would add a UVB/A T5 (or in car terms a methonal kit) that would add a few mpg while increasing standard octane gas to premium and dropping the temperature reducing any knock to 0.

Yodaweed said:

If your area is properly lit you won't see an increase in yield, plants can only absorb so much light and the light source isn't the most important thing as long as you are getting around 600-900 PPFD. These people that said they doubled or tripled their yield must have been terrible growing with HID lights, if i tripled my yield i'd be getting 3 grams per watt i'm pretty sure that's impossible. There is a whole hell of a lot of opinion on this section of the forum, not much to back those opinions up besides bashing and name calling, not much fact or science . You won't see many side by side grow logs of LEDs vs HID lights because usually they don't work out well for the guy who spent 10x more to cover the same area and yields slightly less. Just watch greengene's 1000w hps vs AT600 grow log, he confined his 1000w HPS to a 4x4 to give the AT600 the advantage (a 1000w hps easily covers a 5x5 with the proper reflector) and still yielded a few ounces less with the LEDs than the HPS. If i were looking to get a new light source i'd look into CMH lights, LEDs are just too costly, for what they are, they have zero UV, zero far red, HID lights are still superior.

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Look at my last journal. I harvested my hps room one week before my led. Gpw for bothe were documented using the same strains cut from the same mom. Each plant is broken down to its gpw for both.

Yodaweed said:

If you don't yield more , what's the point? Saving 30$ a month in electric? That's like 2 grams of weed. Some people need the heat, it was -10F already this year where i live, my grow room is 68F with all my HPS lights running. Proper ventilation and heat exchange will do wonders for any grow.

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I used to say the same thing as a decent size hps grower.
Now, my electric bill is cut in 1/2 & I'm flowering twice as many plants in one room
& am Looking to get a 3# increase in yields.
It's all in my journals. I'm only here to share the truth as most people know. Not to get likes or make friends, although I appreciate the ones I have made.

What you say about hps & MH is true though to an extent. Hps grows bigger buds & promotes the second growth spurt, MH provides them more color, trichs & terps. Hps & MH will provide more plant Vigor, thicker stalks.
But a good color balanced led such as white or enhanced white will come pretty darn close to doing all these things while saving a ton on electricity (in a larger setting) & because the spectrum is much fuller, the bud is frostier w/ higher terps then hps.
So, good led gives higher quality & better gpw (save Electric) while matching or exceeding g/sq'.
These are facts Yoda. I document it all in my journals for everyone to see.
Not to mention I compared them for a year before making the solid switch.

Who ever changed this to my 7 second video made my day lol

Stephenj37826 said:

See above post link. Exact environment isn't what I'd shoot for. LEDs need to be ran at a higher ambient temperature. If you ran the HPS side at 84(LEDs sweet spot) it would be too hot for the HPS plants. Vise versa if you ran the LED side at 78(HPS sweet spot) you'd be running to cold for the LED side.

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Cites? Sources?

Isn't 84 degrees F maximum optimal leaf temp for Photosynthesis (regardless of light source) in most plants, before diminishing returns i.e. Photoinhibition/photorespiration?

Wouldn't Vapor Pressure Deficit, as well as atmospheric CO2 concentrations, dictate how much a plant can Photosynthesize (with a fixed amount of light/ constant temp)? If VPD is too great, wouldn't 84 degrees F, ambient or leaf surface, be substantially too warm for plants?

Well I guess that would be dependent on the amount of radiant light (ppfd). And the spectrum too since some 'colors' of light are less easily absorbed and serve to mostly raise leaf temps. Do monochromatic fixtures raise leaf temps as equivocally as white phosphor chips (using same wattage)?

Seems like optimal leaf temperatures depend on a lot of different variables that don't often stay the same.

cdgmoney250 said:

Cites? Sources?

Isn't 84 degrees F maximum optimal leaf temp for Photosynthesis (regardless of light source) in most plants, before diminishing returns i.e. Photoinhibition/photorespiration?

Wouldn't Vapor Pressure Deficit, as well as atmospheric CO2 concentrations, dictate how much a plant can Photosynthesize (with a fixed amount of light/ constant temp)? If VPD is too great, wouldn't 84 degrees F, ambient or leaf surface, be substantially too warm for plants?

Well I guess that would be dependent on the amount of radiant light (ppfd). And the spectrum too since some 'colors' of light are less easily absorbed and serve to mostly raise leaf temps. Do monochromatic fixtures raise leaf temps as equivocally as white phosphor chips (using same wattage)?

Seems like optimal leaf temperatures depend on a lot of different variables that don't often stay the same.

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84F ambient would yield lower leaf surface temps than ambient when using led. Yes optimum leaf surface temp isn't constant..... What is constant is all other conditions being the same the HPS leaf surface temperatures will be higher vs led. Which leads to the need to run different ambient temperatures to obtain equal real world Photosynthetic potential.

Stephenj37826 said:

84F ambient would yield lower leaf surface temps than ambient when using led. Yes optimum leaf surface temp isn't constant..... What is constant is all other conditions being the same the HPS leaf surface temperatures will be higher vs led. Which leads to the need to run different ambient temperatures to obtain equal real world Photosynthetic potential.

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this is true.