Ppfd :-)

Kingrow1 said:

Ya led is anything but clear cut yet.

Consider this though - not many plant species go past 1000umol indoors according to most data ive read.

Outdoors at peak sun they may push 1500+ but that is for a short time and much lower values either side for many hours. Indoors 1000 gives a respectable daily light integral dli like any good outdoor spot for flowering.

I find mj not such a high light plant as we think and those in very bright hot places use much thinner leaves than say your afghan variety.

More speculation for me atm but i hope to dial.in light and see increased results eventually

Click to expand...

That's an interesting thought. My plant in the ground this summer was a Bakerstreet, which if you believe the breeder is a Hindu Kush landrace. It started indoors with the second fattest leaves I've ever grown, but as she got bigger outdoors and temps got above 30 C the leaflets got a lot thinner. Not as thin as my neighbour's sativa, but fairly close.

Kingrow1 said:

Ya led is anything but clear cut yet.

Consider this though - not many plant species go past 1000umol indoors according to most data ive read.

Outdoors at peak sun they may push 1500+ but that is for a short time and much lower values either side for many hours. Indoors 1000 gives a respectable daily light integral dli like any good outdoor spot for flowering.

I find mj not such a high light plant as we think and those in very bright hot places use much thinner leaves than say your afghan variety.

More speculation for me atm but i hope to dial.in light and see increased results eventually

Click to expand...

You're trying led now?
I also believe there is a difference between the way the plant responds to an even ppfd & a hot spot ppfd.
A hotspot ppfd could be more like the sun causing transported energy to lower par sites. Plant energy transfer. Light mover or plant mover reduces center hotspots.
Now an evenly spread ppfd can be overwhelming to her if to intense. Which is way less then what the hotspot light reads in the center.

You end up seeing a lot of threads where peeps who buy indica grow it believing its sativa because the leaves got thin when it got stressed.

Thin leaves deal with moisture better, light and air temps can really deplete a leaf of that. Cut a leaf and leave in full sun all day and it be crisp, thats how easily a leaf can suffer if it isnt kept fully saturated

CanadianJim said:

That's an interesting thought. My plant in the ground this summer was a Bakerstreet, which if you believe the breeder is a Hindu Kush landrace. It started indoors with the second fattest leaves I've ever grown, but as she got bigger outdoors and temps got above 30 C the leaflets got a lot thinner. Not as thin as my neighbour's sativa, but fairly close.

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Excellent point - hadnt thought of that

Im not trying led anytine soon but possibly t5 leds in the near future as i own the fittings already - pay £15 a t5 24watrs so might be similar costs.

Actually ive seen leds grow from those first ufo base units to what is todays market and quite happy hps can compete in every way zero problems. Like you more intrested in dialling in any light which for me happens to be largely hps

hybridway2 said:

You're trying led now?
I also believe there is a difference between the way the plant responds to an even ppfd & a hot spot ppfd.
A hotspot ppfd could be more like the sun causing transported energy to lower par sites. Light mover or plant mover reduces center hotspots.
Now an evenly spread ppfd can be overwhelming to her if to intense. Which is way less then what the hotspot light reads in the center.

Click to expand...

Kingrow1 said:

You end up seeing a lot of threads where peeps who buy indica grow it believing its sativa because the leaves got thin when it got stressed.

Thin leaves deal with moisture better, light and air temps can really deplete a leaf of that. Cut a leaf and leave in full sun all day and it be crisp, thats how easily a leaf can suffer if it isnt kept fully saturated

Click to expand...

I fully believe it was an indica. The leaves it had indoors showed that perfectly. I just don't fully trust some of the breeders out there. As far as leaves getting thin due to stress, I see it as adaptation to local conditions. I suppose you could call it stress, however "stress" implies something that harms growth or yield.
But that would just be quibbling over semantics.

Kingrow1 said:

Excellent point - hadnt thought of that

Im not trying led anytine soon but possibly t5 leds in the near future as i own the fittings already - pay £15 a t5 24watrs so might be similar costs.

Actually ive seen leds grow from those first ufo base units to what is todays market and quite happy hps can compete in every way zero problems. Like you more intrested in dialling in any light which for me happens to be largely hps

Click to expand...

You'll see a minor difference between the 2.
Not double the light output for sure.
100w, 160-70 lm/w of strips = 480w T-5.
That's just veg talk. Flower n talk to me.

Kingrow1 said:

Well that was the purpose of the thread, im finding light levels for each stage and that most of the info and light charts have me too close at times and working in ppfd or umols gives me a better scale.

Leds are great lights, their history and attitude here let alone failings to discuss why that shitty hps spectrum they were meant to kill does so darn well less than reputable.

Some suggested i was inviting led argument... this just one in many environment threads where im trying to pin exact numbers down and ive done the same for wind speed recently amongst one or two other topics like temps. Ive seen research labs grow other plants using all this data and just wanted to get to that level and also work out the set for mj.

I see seedlings at 100-200umols but this is just taken from base info and leaves a 4x24w t5 unit let alone 250w hps pretty high above jusr to achieve such low level. So is this why seedlings can do so well in windows but bum out under lights.

I grow but i have so.much fine detail ahead

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My clones/seedlings are at 80-120. And that puts them at the rate I need. I think most people have an unrealistic idea of how much light you need and how close you need fixtures. When you hit 1200umol or so you end up carb limited, not light limited. You’re more or less at the point of saturation.

hybridway2 said:

Cmh has been known to equally perform to a 600w hps. Same growers hands. Because of spectrum. Better weed.

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I haven’t seen this personally. Quality is definitely improved, but I pull about 100-150g less with a 315 than a super 600. I would be interested in seeing a side by side of anyone that claims to do better with 300 watts than 600, even with a better spectrum. 600se hps puts out almost twice (1100umole)the ppfd as a 315(590umole) so I don’t know how this claim would work in pretty much any situation.

I have seen just over a pound with a 315, but I’ve personally gotten around 2 with a 600 and never over 1# with my 315s.

Kingrow1 said:

Sometimes hps can be a bit of a beast with a whacking great hot spot underneath if too close,

Click to expand...

have you tried a spreader underneath the lamp already?

CanadianJim said:

I fully believe it was an indica. The leaves it had indoors showed that perfectly. I just don't fully trust some of the breeders out there. As far as leaves getting thin due to stress, I see it as adaptation to local conditions. I suppose you could call it stress, however "stress" implies something that harms growth or yield.
But that would just be quibbling over semantics.

Click to expand...

also later in flower its possible to use the form/looks of the buds to see if its sativa or indica or a hybrid

Kingrow1 said:

less light from the led favoured them more than the brighter hps and less stress equalled more yeild

Click to expand...

if that would be true all you'd to do is increase the distance of your hps to your canopy and hps should even out. More so: this would even increase the area which that hps could support, resulting in a doubled bonus. The result should be outstanding.
But thats not what I witness...

Kingrow1 said:

Sometimes hps can be a bit of a beast with a whacking great hot spot underneath if too close,

Click to expand...

like being said, this problem can easily be overcome by using the right distance.
When I grow under hps, the plant vertically beneath it is either a slow growing indica or gets heavily topped, the plants to the sides however are allowed to shoot higher.
You grow thr canopy in the form of a *sphere* surrounding the lamp. that does mostly away with this hotspot.
further, the form and size of the reflector is also crucial to this. I see alot if silver ones which will negatively change the spectrum. Only white remains color-true

CanadianJim said:

That's an interesting thought. My plant in the ground this summer was a Bakerstreet, which if you believe the breeder is a Hindu Kush landrace. It started indoors with the second fattest leaves I've ever grown, but as she got bigger outdoors and temps got above 30 C the leaflets got a lot thinner. Not as thin as my neighbour's sativa, but fairly close.

Click to expand...

Intriguing thought. A direct comparison of 2 clones in 2 different tents running under different light/temps at the same time with most other parameters as close ad possible would perhaps be able to further clarify this mechanism.

hybridway2 said:

Light mover or plant mover reduces center hotspots.

Click to expand...

I've seen some growers moving plants around - results were poor. plants need to readjust, which uses up energy, and until its finished, photosynthesis suffers bc light falls onto leaves in a bad angle.
the stationairy light is a big bonus of indoor growth IMO.
as for moving the light, that may work... but only if the canopy is flat not spherical around HID.

CanadianJim said:

suppose you could call it stress, however "stress" implies something that harms growth or yield.

Click to expand...

if leaves get too hot photosynthesis will suffer due to increased water evaporation for cooling. isnt there a chart around here which displays that mechanism? thats why hps cannot beat led - too much excessive heat radiation

You know how low 80-120 is though?

Ive run this enough not to disagree but that rewrites a lot of info. My t5s need to go higher still and i have them higher than most.

At 50cm a 250w hps hits 400umol at centre as the data ive tried to find suggests, at a meter were still not at 200 in a 60x60.

I was recently annoyed by this or maybe unprepared to run hps for veg over my t5s

kmog33 said:

My clones/seedlings are at 80-120. And that puts them at the rate I need. I think most people have an unrealistic idea of how much light you need and how close you need fixtures. When you hit 1200umol or so you end up carb limited, not light limited. You’re more or less at the point of saturation.

Click to expand...

No transpiration is mother natures most efficient cooling system, even humans and big industry use similar energy transport water cooling systems due to their high efficiency.

At a certain ligh saturation too much heat is generated and cannot be dispersed which is infinitly more damaging than ir which is easily budgeted for. Singlet and triplet oxygen damage is high on a leafs stress and repair list. Ir is natural and dosent just heat leaves but soil as does light when it strikes stuff.

Leds falsley say to increase air temps to make up for lack of natural spectrum warmth, this would slow down water transport and growth not speed up. There is a lot of bad or bending of science leds can do and basically did which made the whole subject very toxic, oh that whole leds need more cal mag science bending and every bending of spectrum they always fail with

Kassiopeija said:

if that would be true all you'd to do is increase the distance of your hps to your canopy and hps should even out. More so: this would even increase the area which that hps could support, resulting in a doubled bonus. The result should be outstanding.
But thats not what I witness...


like being said, this problem can easily be overcome by using the right distance.
When I grow under hps, the plant vertically beneath it is either a slow growing indica or gets heavily topped, the plants to the sides however are allowed to shoot higher.
You grow thr canopy in the form of a *sphere* surrounding the lamp. that does mostly away with this hotspot.
further, the form and size of the reflector is also crucial to this. I see alot if silver ones which will negatively change the spectrum. Only white remains color-true


Intriguing thought. A direct comparison of 2 clones in 2 different tents running under different light/temps at the same time with most other parameters as close ad possible would perhaps be able to further clarify this mechanism.


I've seen some growers moving plants around - results were poor. plants need to readjust, which uses up energy, and until its finished, photosynthesis suffers bc light falls onto leaves in a bad angle.
the stationairy light is a big bonus of indoor growth IMO.
as for moving the light, that may work... but only if the canopy is flat not spherical around HID.


if leaves get too hot photosynthesis will suffer due to increased water evaporation for cooling. isnt there a chart around here which displays that mechanism? thats why hps cannot beat led - too much excessive heat radiation

Click to expand...

Ive just not used hps for seedlings much, it made me think i have to know light levels better

Kassiopeija said:

have you tried a spreader underneath the lamp already?

also later in flower its possible to use the form/looks of the buds to see if its sativa or indica or a hybrid

Click to expand...

Kingrow1 said:

You know how low 80-120 is though?

Ive run this enough not to disagree but that rewrites a lot of info. My t5s need to go higher still and i have them higher than most.

At 50cm a 250w hps hits 400umol at centre as the data ive tried to find suggests, at a meter were still not at 200 in a 60x60.

I was recently annoyed by this or maybe unprepared to run hps for veg over my t5s

Click to expand...

I have a par meter so It is what I actually have, mother’s at 200 or so. I’m really not looking for growth rate until they hit the veg space, then they’re 500-900umole

Kingrow1 said:

No transpiration is mother natures most efficient cooling system, even humans and big industry use similar energy transport water cooling systems due to their high efficiency.

At a certain ligh saturation too much heat is generated and cannot be dispersed which is infinitly more damaging than ir which is easily budgeted for. Singlet and triplet oxygen damage is high on a leafs stress and repair list. Ir is natural and dosent just heat leaves but soil as does light when it strikes stuff.

Leds falsley say to increase air temps to make up for lack of natural spectrum warmth, this would slow down water transport and growth not speed up. There is a lot of bad or bending of science leds can do and basically did which made the whole subject very toxic, oh that whole leds need more cal mag science bending and every bending of spectrum they always fail with

Click to expand...

What are you talking about?

Kassiopeija said:

if that would be true all you'd to do is increase the distance of your hps to your canopy and hps should even out. More so: this would even increase the area which that hps could support, resulting in a doubled bonus. The result should be outstanding.
But thats not what I witness...


like being said, this problem can easily be overcome by using the right distance.
When I grow under hps, the plant vertically beneath it is either a slow growing indica or gets heavily topped, the plants to the sides however are allowed to shoot higher.
You grow thr canopy in the form of a *sphere* surrounding the lamp. that does mostly away with this hotspot.
further, the form and size of the reflector is also crucial to this. I see alot if silver ones which will negatively change the spectrum. Only white remains color-true


Intriguing thought. A direct comparison of 2 clones in 2 different tents running under different light/temps at the same time with most other parameters as close ad possible would perhaps be able to further clarify this mechanism.


I've seen some growers moving plants around - results were poor. plants need to readjust, which uses up energy, and until its finished, photosynthesis suffers bc light falls onto leaves in a bad angle.
the stationairy light is a big bonus of indoor growth IMO.
as for moving the light, that may work... but only if the canopy is flat not spherical around HID.


if leaves get too hot photosynthesis will suffer due to increased water evaporation for cooling. isnt there a chart around here which displays that mechanism? thats why hps cannot beat led - too much excessive heat radiation

Click to expand...

Im trellissed n locked in. Not with hps but with my white led, the centers of the plants take a beating.
Still growers error for me as i see others w/o the problems i face but see allot more facing them too.
I call it LedDefficiency.
Yeah, they hate that word over in the led section . But so many growers w/ what seems to be the exception of soil growers & that select radical few who nail it. The rest are half way there claiming they got it down 100% like @lukio For instance. The many that think they're good but still face early fading, occasional defficencies & pale leaves are usually the ones whom never used HPS/MH , therefore have no truly proven Horticultural/street light to go by. So they start going by the successors of led growing in Soiless medias methods. Some work better then others but it always comes down to a change in nutrient profile & usually VDP. 2 Things that never seemed to harm me under hps in a well less equipped room. As well as DTW now. Didn't have to keep run-off in check before.
Even the successors of led growing still get purple petitoles, which hasnt proven to cause damage like the purple stem does.
Idk! Been at it for awhile. Sometimes i get results that make me wanna sell all my hps thats collecting dust.. other times i wanna smash my LEDs.
Just to inconsist for me. But when you nail it, you freaking nail it. Like some plants in my room rn. Hps could never do that.
So, its a headache till its dialed. For me anyways.
Edit:
Not to be of topic, i feel led ppfd & hps ppfd are different #'s to be optimal for me in my room. So many more points of light coming at the plants, there is nowhere to hide or catch some shade unless its under the canopy (where all the healthy leaves are or on the edges)
But i see others w/o this issue. So, ima follow their lead if i can.

hybridway2 said:

Im trellissed n locked in. Not with hps but with my white led, the centers of the plants take a beating.
Still growers error for me as i see others w/o the problems i face but see allot more facing them too.
I call it LedDefficiency.
Yeah, they hate that word over in the led section . But so many growers w/ what seems to be the exception of soil growers & that select radical few who nail it. The rest are half way there claiming they got it down 100% like @lukio For instance. The many that think they're good but still face early fading, occasional defficencies & pale leaves are usually the ones whom never used HPS/MH , therefore have no truly proven Horticultural/street light to go by. So they start going by the successors of led growing in Soiless medias methods. Some work better then others but it always comes down to a change in nutrient profile & usually VDP. 2 Things that never seemed to harm me under hps in a well less equipped room. As well as DTW now. Didn't have to keep run-off in check before.
Even the successors of led growing still get purple petitoles, which hasnt proven to cause damage like the purple stem does.
Idk! Been at it for awhile. Sometimes i get results that make me wanna sell all my hps thats collecting dust.. other times i wanna smash my LEDs.
Just to inconsist for me. But when you nail it, you freaking nail it. Like some plants in my room rn. Hps could never do that.
So, its a headache till its dialed. For me anyways.

Click to expand...

I’ve noticed some strains like one light source better than others. Some respond well to led, some to cmh, but hps grows everything well.

hybridway2 said:

I call it LedDefficiency.

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normal people just call it lockout.

hybridway2 said:

The rest are half way there claiming they got it down 100% like @lukio For instance

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bro, my plants are loving life under led, again You're the minority

hybridway2 said:

The many that think they're good but still face early fading,

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youre just making that up.

please dont tag me in this nonsense

lukio said:

normal people just call it lockout.


bro, my plants are loving life under led, again You're the minority


youre just making that up.

please dont tag me in this nonsense

Click to expand...

Just messing with ya man. You'r alright in my book despite your HGL infatuation. Lol!
How you do it at 1 ec is beyond me? NM, smaller the plant, lower the EC.
I am deffinetly not the minority. Google that shit dude. Imagine how many more there are who are just to embarrassed to say it. Especially after seeing others results.
It is Growers Error cuz you gotta know your shit or start that way with proper advising of led.
Ok man, Peace! Thnx for taking the time.
Can we see some if that Beautiful Bean Footage?

lukio said:

bro, my plants are loving life under led, again

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yeah 'cause you finally gave them the spectrum they needed. red blue and GREEN. that's some NASA shit right there m8.