LED and BUD QUALITY

[CannaT]

Hard time to see much difference, at least in sparkle. Surprising similar in morphology, not what i would expect.

In this case the led bud seems to sparkle more but i think thats down to the lighting, hid bud has lower and less direct light on it. Hid bud looks a bit fluffier and less dense.

Again hard to evaluate due to differences in lighting. The last one of the HPS pic does look great, i happily admitt bit not really a slam dunk case imo.

This one actually shows something re morphology: led bud looks denser and with a bit darker sugar leaves. This is quite usual in led buds, less infra red and heat usually leads to anthocyanin accumulation which many times lead black/purplish coloration

In general: there seems to a bit of difference in trim technique and how deep you trim. They seem a bit small, like the one from my failed crop. Trichomes look fairly similar in most cases. Best looking bud for trichome cover is the HID bud i mentioned specially.

Again, wheres the relevant argument? This is a thread about led bud quality, how to achieve it etc. If youre argument is that without HPS infrared theres no trichome coverage i cant really see that you shown a clear case. In my opinion if there ever was an argument for hps and quality it would be that even though it has minimal blue (usually ive seen quoted 6% rather than 10%) the little blue is spread out over a larger section of the spectrum. But sorry no sorry i dont really see that as a "gotcha, hps > led".
If you want help growing better with leds please hit me up over PM and ill help you out, its not difficult to setup a uv channel with continuous coverage of blues an uv. Or even a nice wide red sup for more volatiles. Stop sounding your voice just cause you cant get on board with the subject matter: how to grow better weed with leds. Im sure there are plenty of threads that have the subject of led vrs hps. If you read the paper i posted you could maybe begin to get an idea why HPS create quite good results aswell, though with more watts and heat. Did you ever grow in a really hot climate? Both lights have its advantages and disadvantages depending on climate. Nobody is making you grow with leds here. Hope it helps

Im the worst for triming plants machine trim better than me.

 

[CannaT]

@CannaT you are still fixated on hps vs led and that is not what this thread is about. remember vinyl records? how they would get stuck on a groove? and you had to bump the turntable to get it off?

you are stuck the same way.

nobody gives a shit about a smackdown between two light sources except for you.

nobody is going back to hid lighting as a sole source. it's fixed, non-tunable, and creates too much heat that must be offset with too much a/c.

out of the 28 years i've been growing i have 23 years using mostly hps and metal halide. some cmh experience as well. i can show you pics of some of the heaviest plants to be shown on icmag grown with hps.

with hps you have a fixed spectrum that is not ideal but does a good job, not a great job.

the led has opened up a whole new world of possibilities because the grower is not restricted to a fixed source.

custom led builders are entering new, uncharted territory in plant lighting that would not be possible with a fixed spectrum source.

you do not offer solutions. you just keep banging away with "hps rules, dude"!

have you considered what parts of the hps spectrum produce the results you like? any part of the hps par spectrum is reproducible using leds.

there's nothing magical about hps that sets it apart from other light sources. it's simply a different combination of spectra.

i am growing high yielding, dense, high potency, high terp profile flowers with a combination of led and incandescent.

i could do it with leds alone but not as economically as i can with this combination.

i arrived at this combination by examining the hps and led spectrums and finding the obvious missing parts in each.

i am not done experimenting yet. i used 5000k for veg and the first 3 weeks of flower, the stretching phase. then switched them for 2700k plus incandescent for the duration of the grow.

in this thread folks have mostly been focused on the flowering spectrum. i think the ultimate solution is a completely tunable light that works in all phases of growth. you will not ever be able to achieve that with hps technology. it's a dead end path.

research has shown that a red-weighted spectrum produces mass but at the expense of quality. a blue-weighted one produces better quality but at the expense of mass.

i think that by manipulating the spectrum at different points of the plants' life you can have both.

you will never be able to do that with hps technology.

the plant exhibits hysteresis in many functions, such as acquired stomatal resistance to drought. that is, the plant reacts to previous entraining by abiotic stress and continues that entraining into a non-drought situation.

there is a lag time in the start up of photosynthesis when the lights come on. in my system, the ppk system, this is readily demonstrated by turning off the top watering apparatus during the dark phase and then observing the float valve when the lights turn on.

the system is sub-irrigated as well as top-irrigated. the sub-irrigation is accomplished via a tube filled with media displaying capillary rise that is in contact with the reservoir. so the plant draws water upward. the amount depends on many factors.

when the lights first turn on you can observe an occasional drip from the float valve. as you watch, this drip increases in frequency until it is a steady, rhythmic, drip, drip, drip. it takes about 30 minutes to reach this state.

what i witnessed was the lag time in the startup of photosynthesis.

i use this example and the stomatal entraining just to illustrate that the plant's responses all have a lag time.

and can be entrained to conditions.

it seems to me that training a plant with one spectrum and then switching to another both retains the characteristics of the first, at least for some time, as it simultaneously begins to exhibit the characteristics of the second. there is a possibility of creating a synergistic effect by manipulating light spectrum.

plants don't have vascular or nervous systems. they are hormonally driven.

it's a chemical signalling system. increasing or lessening the signals in reaction to external conditions.

you will never be able to explore this kind of stuff by using hps lighting where the manufacturer dictates the spectrum.

this flower was grown with led plus incandescent. it is the first time i have gotten hps size flowers that also have great potency and terpene profile.

it is one of the most potent strains i have ever grown, and it reeks to high heaven!

so, please, pretty please with sugar on it, help us complete the puzzle!


View attachment 19044016


View attachment 19044017

So you use led + something its ok atm Im also using 50% hps 50% leds...and maybe like it the best.
Will try 30%leds 70% hps....
Im doing my own experiments and here I say about my expiriences.
I said 1000000 times that I know that you can made out of led any light spectrum...Im just debating here about Led boards that you can buy in regular growshop these days.

 

[Rocket Soul]

Im the worst for triming plants machine trim better than me.

Fair dues but can we drop this now?. We all grow weed dont we? Youre kinda coming off like someone who just want to annoy and be contrarian. Fair dues again and id be guilty of that as well sometimes but i try not to do it here or to other growers. If youre actually into that i just ask you to go and do it to someone in the real world rather than bothering other growers. There are plenty of people in real life that deserve a nice argument, go bother them.
Or maybe we can all chip in for this on your birthday:


I joke a bit and i respect a man for standing their ground and for their opinions but its also a virtue and sign of intelligence to understand how you come off to the people around you. Youve not come off great here but im sure youre not a terrible person. After all you grow and smoke so how bad could you be?




I think the HID plus led approach is very valid. Greyfader made it work with incandescants which is also cool. I wanna try this myself some time but its hard for me to push for whatever i want in the grow since we are several people and dont have an infinity of amps and AC. Low K high cri whites + incandescant/halogen or similar + wide uva + uvb would be a killer combo covering everything you seem to like better than just plain hps. Maybe this winter but i already have my experiment schedule quite full, hard to do everything at the same time.

If youre already into experimenting then get on board and lets move the knowledge forwards instead of insisting that there will be no good weed unless we all go back to before.

The leds you can buy that have what you need are here on the forum: Growlights australia in the sponsor section. Awesome gear, not only on spectrum and efficiency, theyre fully sealed so you can hose them down. But obviously at a premium price. Ymmv and peace

 

[Ca++]

No and also not in my experience with the migro uv lamp.

Non of my trials were fruitful either.
I do note they used 80umol, or almost 10% extra lighting load, just on their UV idea.
Bugbee in comparison, seems to have a graph labeled in fractions of a umol. So low in fact, that something must be wrong.

I tended to stick a lot of UV in the corner, so got a wide spread of levels. From bright under it, to weak across the room. Too much hurt them. That's all I could manage. I have visited this on 3 occasions, to satisfy myself I'm on the right path. Today there seems enough data coming in from bigger trials, to no longer have to do such things myself. The more holistic picture appeals to me now. Where blue light trials are not that much different to the UV one's. Leaning me away from that end of the spectrum.

 

[greyfader]

I think the HID plus led approach is very valid. Greyfader made it work with incandescants which is also cool. I wanna try this myself some time but its hard for me to push for whatever i want in the grow since we are several people and dont have an infinity of amps and AC. Low K high cri whites + incandescant/halogen or similar + wide uva + uvb would be a killer combo covering everything you seem to like better than just plain hps. Maybe this winter but i already have my experiment schedule quite full, hard to do everything at the same time.

If youre already into experimenting then get on board and lets move the knowledge forwards instead of insisting that there will be no good weed unless we all go back to before.

The leds you can buy that have what you need are here on the forum: Growlights australia in the sponsor section. Awesome gear, not only on spectrum and efficiency, theyre fully sealed so you can hose them down. But obviously at a premium price. Ymmv and peace

my view on supplementing leds with hps is that you are unnecessarily duplicating a large portion of the spectrum at a much greater cost than with incandescents supplementing only the needed part.

for instance, you don't need the blue or the green from hps if you have all the blue and green you need from white leds. it's the red spectrum above 630nm that needs to be supplemented. possibly dark red and far red as well.

you shouldn't use one large hps bulb as it will be too big and too hot to get the bulb on the same working plane as your leds.

so you need several smaller ones. the smallest i could find is a 35 watt bulb. in my experimental grow shown above i used 6 25 watt incandescents spread evenly over the canopy at the same working height as my leds. so, you would need approx 4.28 35 watt hps bulbs to equal the 150 watts from six incandescents.

the purchase price of the bulbs plus ballast is much greater than incandescent.

35 Watt High Pressure Sodium - ANSI S76 - LU35 - Plusrite 2000 | 1000Bulbs.com

Find the best price on 2000 today at 1000bulbs.com! We are the #1 online retailer for all things lighting!

www.1000bulbs.com

Sola E-SRN00F35 | HPS Ballast | 35 Watt | 1000Bulbs.com

Light your HID Lamps with Sola E-SRN00F35 35 watt High Pressure Sodium Ballast. 120 volt Magnetic HID Ballast on sale at 1000Bulbs.com!

www.1000bulbs.com

the combined cost of the bulb and ballast combination is $33.73 and you would need at least 4 so the total cost of supplementing a single 1000 watt led light would be a minimum of $134.92

i used these incandescent bulbs;

25W, Clear, Incandescent A15 Bulb, Medium Base, 130V, PLT NORM-10002 | 1000Bulbs.com

Get the PLT 25A15CL130V, a 25-watt A15 light bulb that gets the job done, inexpensively. Shop from huge selections of incandescent A15 bulbs at 1000bulbs.com!

www.1000bulbs.com

at .93 cents each so 6 would be $5.58. a radical difference. these are A15 envelope bulbs not A19 like household light bulbs. the A15 bulbs are smaller for the same wattage. they are appliance bulbs designed for temperature extremes. oven or freezer. they are vibration-resistant. they are still intact and working after 2 grows.

in places where the A19 household bulbs are banned these appliance bulbs are still available and probably will be for a long time. and quartz halogen, which has a close resemblance in spd to incandescent, is used in medical grade optical equipment. they will always produce them.

looking at spectrum this is what i used from the end of week 3 of flowering to finish. this shows a generic 2700k led superimposed with a 25 watt tungsten incandescent. this assumes equal power but i have no way of measuring the differences that would occur using incandescent at 16% of total power, which is what i used. if anyone has any input on that i could use some help here.

notice how the curve of the incandescent takes over at around 630nm. and then continues upward supplementing more dark red as a portion of par than the sun itself. a smooth continuous curve that goes on into far red and infrared red. triggering the phytochrome shade-avoidance response which, in flower, could be called the mass-building response. in the vegetative phase this causes elongation but once the stretch phase is done and flower set has occurred you don't have elongation. you get mass instead. notice that the incandescent has significant near UV as well.

this is a generic hps spd chart. notice how the curve drops off after the spike at around 630nm.

and, again, this shows how closely the incandescent follows the action spectrum above about 550nm.

 

[Ca++]

It's not very scientific, but I just grew under LED, with a HPS to the side. They went straight to the HPS, and the buds under it, well...
It seems easy to put over 1000umol on plants with an HPS, that seems unhappy under more than 650umol of LED. All other things being equal.
This echo's what a lot of people have said, regarding LED being harder to work with. It also fits the papers on blue, where 1% more blue, means 2% less yield. Much like some UV trials, though they notice before the weigh-in usually, and start switching them off (then on again?)

I might be that non-existent grower, that tried LED for a number of years, then went back to HID with LED assistance. It might not say a lot about my growing, but that more forgiving sodium light, means I can stick in more, and the extra cost of running them, is returned. I'm doing better mixing the lights, than using either alone.

One driving force for me, is that I want that heat. Warming a grow in the UK isn't easy, when your extraction is optimal. More power goes in heating than lighting, for most of the year. The radiant heat aspect might be huge for me, as it warms the plants, only where needed (and expected) instead of the whole grow, in a manner easily removed.


A bit a reflection I hope, rather than totally off topic.

 

[I Care]

XS2500 Pro vs the Sun

Indoor Strawnanna Hybrid 2wks 12 dark

Outdoor Bubba Kush

When compared to the sun, an LED is much more reliable and does what you want when you want. The sun is still reliable, Its free and it’s always burning but it will never be domesticated like an LED.

There is of course the limitless power of the sun that allows to grow large plants, but this thread is about LED.

It’s obvious that I already have better buds compared to the plant that is waiting on the sun. LED wins 11 months out of the year.

 

[I Care]

I ordered the 2200k LED Filament bulb I been wanting since I found out about them last year. I didn’t take pictures cause I was watering plants as my work for the day. This bulb comes as a glass bulb, HPS 2200k so there should be no blue. Bugger was expensive and I’m putting in an overtime week so I might not get one of the dome reflectors rigged up with a plug this weeeknd. But, I will post action shots soon.

going to try to find someone with PPFD instruments to smoke out with

 

[I Care]

That's so much info to collect it becomes difficult to compute all these different datas. I've noticed some of the clones I'm running don't have enough internodal spacing but not all strains react the same way, even in the same seeds some individuals will behave differently about stretch and that's something I'd like to homogenize if possible. The idea is to find a way to boost the stretch of some plants and limiting the size of the taller one, it's easier to cut a plant than elongate it by pulling on it

kro, you should listen to the interview migro guy does with the bugbee. the interview is conducted very well with all the right questions a bug we definitely says that light is the most effective way of crop steering cannabis. Possibky in this thread, but somewheres I processed the memory of suggesting red is what Will produce more growth or intermodal spacing.

The explanation Is that when the plant sees more red light, it will stretch to get into the more broad spectrum light. The reason that plants grow taller in the shade is that there is actually more red light in the shade.

Some people would flip to dark with MH and then go to HPS after the start of flower to slow the stretch. My personal experience with HPS is that the taller diesel pheno I grew many years ago stretched above the light in early flower, while I was on vacation. When I returned I had to remove my flood table and also bruise the tops to hang horizontal to accommodate. I believe if I had also included the veg CFL over those two plants during the first couple weeks or if I had a MH and used that for the first two weeks I would have had less stretch.


this might even be why some led bud sucks, cause the cultivar is already a dense producer selected under HPS or maybe in the shade like they used to grow the indices. then take a classic under the 5000k diodes the whole way through and maybe they perform well but not as good as they would with the less par efficient 3000k

 

[kro-magnon]

kro, you should listen to the interview migro guy does with the bugbee. the interview is conducted very well with all the right questions a bug we definitely says that light is the most effective way of crop steering cannabis. Possibky in this thread, but somewheres I processed the memory of suggesting red is what Will produce more growth or intermodal spacing.

The explanation Is that when the plant sees more red light, it will stretch to get into the more broad spectrum light. The reason that plants grow taller in the shade is that there is actually more red light in the shade.

Some people would flip to dark with MH and then go to HPS after the start of flower to slow the stretch. My personal experience with HPS is that the taller diesel pheno I grew many years ago stretched above the light in early flower, while I was on vacation. When I returned I had to remove my flood table and also bruise the tops to hang horizontal to accommodate. I believe if I had also included the veg CFL over those two plants during the first couple weeks or if I had a MH and used that for the first two weeks I would have had less stretch.


this might even be why some led bud sucks, cause the cultivar is already a dense producer selected under HPS or maybe in the shade like they used to grow the indices. then take a classic under the 5000k diodes the whole way through and maybe they perform well but not as good as they would with the less par efficient 3000k

Thanks for the tip, I will try to find this interview, the review Migro made of the Lumatek Zeus is what convinced me to get one as he said it was the best light he had seen then.
When I see the difference in stretch between my LED and HPS grows it’s very possible the red play a part in this. I have better yield with shorter plants with LED but sometimes I’d like to see some get taller like my Black Cherry Punch clone who staid very small and compact and too prone to mold because of that.

 

[JKD]

Bugbee/Migro crop steering with temperature

 

[greyfader]

the plant senses the ratio of red to far-red to trigger the elongation response. i think you should suppress the elongation response up throughout the veg cycle and up to the end of the third week of flower with a 10-week strain. and then encourage it for the flower mass-building phase. this creates both larger and more dense flowers.

in addition to light and temperature manipulation, i also use selective defoliation to control nodal spacing. the leaf surfaces contain the most sensing cells and when you remove a leaf you remove the red/far-red signal source. this causes the stem section immediately above the removed leaf to stop elongating.

i don't think it's a good idea to train a plant to stretch. most indoor hybrids have a tendency to stretch and that should be suppressed.

topping also helps with suppressing stretch by re-distributing auxins.

 

[kro-magnon]

the plant senses the ratio of red to far-red to trigger the elongation response. i think you should suppress the elongation response up throughout the veg cycle and up to the end of the third week of flower with a 10-week strain. and then encourage it for the flower mass-building phase. this creates both larger and more dense flowers.

in addition to light and temperature manipulation, i also use selective defoliation to control nodal spacing. the leaf surfaces contain the most sensing cells and when you remove a leaf you remove the red/far-red signal source. this causes the stem section immediately above the removed leaf to stop elongating.

i don't think it's a good idea to train a plant to stretch. most indoor hybrids have a tendency to stretch and that should be suppressed.

topping also helps with suppressing stretch by re-distributing auxins.

Impressive results you obviously know how to get the best out of your plants
It’s possible I already had the same reaction the first time I’ve seen this picture

 

[CharlesU Farley]

One driving force for me, is that I want that heat. Warming a grow in the UK isn't easy, when your extraction is optimal. More power goes in heating than lighting, for most of the year. The radiant heat aspect might be huge for me, as it warms the plants, only where needed (and expected) instead of the whole grow, in a manner easily removed.


A bit a reflection I hope, rather than totally off topic.

For your environmental conditions, it sounds like primary HPS with additional LED is _perfect_ for your situation.

Living in the SouthEast US, I have the opposite problem with regard to environmental temperature and heat production by lighting equipment.

And btw, it was common knowledge, even back in the mid '90s, that light heavily tilted towards the blue spectrum resulted in short inner node length whereas light tilted towards the red spectrum resulted in longer internode length.

You were almost right iCare, but what we did back in the day was veg plants under MH for the short internode length and then use HPS during flowering for bud development, not innernode length or stretch. The red didn't slow the stretch, it made the buds more bigger/ dense.

Since this is a LED thread, this is what I used to use to adjust the lighting spectrum for internode length and bud development :

 

[I Care]

Thanks for the tip, I will try to find this interview, the review Migro made of the Lumatek Zeus is what convinced me to get one as he said it was the best light he had seen then.
When I see the difference in stretch between my LED and HPS grows it’s very possible the red play a part in this. I have better yield with shorter plants with LED but sometimes I’d like to see some get taller like my Black Cherry Punch clone who staid very small and compact and too prone to mold because of that.

I think that’s where comes in the spectrum a traditional horticultural bulb doesn’t have.

are you the one using the same xs2500p as me?
if not man look at the comparison between let’s say the xs1500p that coco tested vs the vs1000 I used to have. Just look at the light and the proportion of diodes that are 3kk or 5kk. There are more proportion of 3kk on one than the other and also same one has lenses.

that 150w is 75 bucks right now and I don’t know why diodes are in it or the efficiency bug

it’s working

Bugbee/Migro crop steering with temperature

yes, it takes a few times listening and watching
he says that light is the best for crop steering

For your environmental conditions, it sounds like primary HPS with additional LED is _perfect_ for your situation.

Living in the SouthEast US, I have the opposite problem with regard to environmental temperature and heat production by lighting equipment.

And btw, it was common knowledge, even back in the mid '90s, that light heavily tilted towards the blue spectrum resulted in short inner node length whereas light tilted towards the red spectrum resulted in longer internode length.

You were almost right iCare, but what we did back in the day was veg plants under MH for the short internode length and then use HPS during flowering for bud development, not innernode length or stretch. The red didn't slow the stretch, it made the buds more bigger/ dense.

Since this is a LED thread, this is what I used to use to adjust the lighting spectrum for internode length and bud development :

View attachment 19056678

🥹





holiday weekend has barely begun but I do love what has come together here. tell me what you think guys, just don’t spit on the chicken salad here. stolidly if I hadn’t spent the bones on this I would buy the xs1500pro on eBay right now while it’s only sevenfive bones shipping out of cali


54w hps 22hk spectrum retrofit high bay

 

[Rocket Soul]

I think that’s where comes in the spectrum a traditional horticultural bulb doesn’t have.

are you the one using the same xs2500p as me?
if not man look at the comparison between let’s say the xs1500p that coco tested vs the vs1000 I used to have. Just look at the light and the proportion of diodes that are 3kk or 5kk. There are more proportion of 3kk on one than the other and also same one has lenses.

that 150w is 75 bucks right now and I don’t know why diodes are in it or the efficiency bug

it’s working View attachment 19056884





yes, it takes a few times listening and watching
he says that light is the best for crop steering


🥹





holiday weekend has barely begun but I do love what has come together here. tell me what you think guys, just don’t spit on the chicken salad here. stolidly if I hadn’t spent the bones on this I would buy the xs1500pro on eBay right now while it’s only sevenfive bones shipping out of cali


54w hps 22hk spectrum retrofit high bay
View attachment 19056885

View attachment 19056887 View attachment 19056888

When looking at hps replacement leds: its good to have in mind that what they are trying to copy is how a hps looks to the human eye, not to a plant. While this would be a decent flower supplement it wont give the same spectrum as a plant sees it.

 

[Hiddenjems]

It's not very scientific, but I just grew under LED, with a HPS to the side. They went straight to the HPS, and the buds under it, well...
It seems easy to put over 1000umol on plants with an HPS, that seems unhappy under more than 650umol of LED. All other things being equal.
This echo's what a lot of people have said, regarding LED being harder to work with. It also fits the papers on blue, where 1% more blue, means 2% less yield. Much like some UV trials, though they notice before the weigh-in usually, and start switching them off (then on again?)

I might be that non-existent grower, that tried LED for a number of years, then went back to HID with LED assistance. It might not say a lot about my growing, but that more forgiving sodium light, means I can stick in more, and the extra cost of running them, is returned. I'm doing better mixing the lights, than using either alone.

One driving force for me, is that I want that heat. Warming a grow in the UK isn't easy, when your extraction is optimal. More power goes in heating than lighting, for most of the year. The radiant heat aspect might be huge for me, as it warms the plants, only where needed (and expected) instead of the whole grow, in a manner easily removed.


A bit a reflection I hope, rather than totally off topic.

I never waste money on heat. Lights are all the heat you need. Extract heat from the tent or room that’s on and heat the tent or room that has the lights off with that heat.

 

[Ca++]

I never waste money on heat. Lights are all the heat you need. Extract heat from the tent or room that’s on and heat the tent or room that has the lights off with that heat.

It's really area specific. You describe Heating one bloom area that is dark, with heat from another that is light. Looking just at the light area, where did it's heat come from. The heat gain from inlet to exhaust, caused by LED lighting, is just a few C if extracting enough to keep RH in range. This puts all the heat demand on the incoming air, as the LED lighting isn't effective at heating that. In many scenarios the heat is leaving LED fixtures as hot air, getting sucked straight out, long before it can get down to the pots. This is alright for the dark area receiving this heated air, but what is the light area being fed.
Typically we are talking tents in bedrooms on forums. The sleeping area of dwellings is heated to 18c as a building design temperature. As the extract takes air from the home, air must enter the home to replace it. If it's winter, this could be 2 or 3c air coming in, that needs to be 25c by the time it reaches the tent. Before it's been anywhere near any lighting. This heating must be done somehow.
I'm actually doing air2air heat exchanges, to warm the cold with the hot. It's a basic trial, but industry has already told us that 50% transfer is an easily achievable number, and 80% heat recovery is a better target to aim for. I would be very happy to pull 80% of the heat out of my exhaust, to warm the inlet.


Changing direction a little, I have seen how HID buds tend to be just 2C hotter than LED, and we correct this with warmer rooms. We warm the room, and total water usage gets back on track.
What we don't see in this, is where the transpiration on the plant occurs. We do know though, that the HID bud was only 2C hotter, because it was sweating like hell to keep cool. The picture of water redistribution isn't a big leap to guess. If we then align this, with the bud redistribution on LED plants, we start to see a picture. It's about where the feed was going with HID, and where it's going with LED.
HID tended to give fewer buds, but they were more impressive to look at. I'm finding the pinnacle bud from each crop, shows a similar distribution. LED giving more of that 80% as good, but somehow the few outstanding bits, are fewer.

This is in part, why I'm heating with a radiant heat source. This HID heat, tends to warm the buds, as much of it is radiant heat. It travels like light does. It can't be sucked away by a fan. Also the HID produces things like strong 730nm, which we know plants use, but isn't counted as useful light. The 730nm HID produces, is classified as waste, when looking at efficiency. Same with an LED fixture that uses 730nm LED's. They don't count towards PAR light. Though in recent times we have started to talk about ePAR or extended-PAR. Where we count light to 750nm as useful. It gets a bit of a grey area, open to interpretation if specifics are not outlined well. The HID obviously continues right past 840nm into nothing but heat. But I feel warming the top buds, to see the feed getting to them more, is pretty much as nature intended. Plus it heats my tops better than using my heating system. As my home heating makes easily extracted hot air, that's 28c if I was lucky. While the same power sent to a radiant source over my buds, heats them without being vacuumed away. It;s more efficient.
For relative examples, we could look at outdoor heaters. A bonfire is bloody hot, because you get the radiant heat from it. The air it heats, actually goes straight up. You can see it go, as it carries to much dust. We just call it the smoke. Hot air is just up and away, but radiant heat travels like light. The patio heater is the same, or the marquee for smokers at the pub. They don't waste money heating air that will be instantly gone. To heat you, they must use a radiant source. This is why in our windy tents, a radiant heat source is good at heating the buds.
For me, I have 19c from the home, heated at intake to about 24, then the HID to warm the buds. This is more efficient than a 28c intake temp.
If you live elsewhere, you may have 28c entering the home, so LED alone is perfect.

 

[Hiddenjems]

It's really area specific. You describe Heating one bloom area that is dark, with heat from another that is light. Looking just at the light area, where did it's heat come from. The heat gain from inlet to exhaust, caused by LED lighting, is just a few C if extracting enough to keep RH in range. This puts all the heat demand on the incoming air, as the LED lighting isn't effective at heating that. In many scenarios the heat is leaving LED fixtures as hot air, getting sucked straight out, long before it can get down to the pots. This is alright for the dark area receiving this heated air, but what is the light area being fed.
Typically we are talking tents in bedrooms on forums. The sleeping area of dwellings is heated to 18c as a building design temperature. As the extract takes air from the home, air must enter the home to replace it. If it's winter, this could be 2 or 3c air coming in, that needs to be 25c by the time it reaches the tent. Before it's been anywhere near any lighting. This heating must be done somehow.
I'm actually doing air2air heat exchanges, to warm the cold with the hot. It's a basic trial, but industry has already told us that 50% transfer is an easily achievable number, and 80% heat recovery is a better target to aim for. I would be very happy to pull 80% of the heat out of my exhaust, to warm the inlet.


Changing direction a little, I have seen how HID buds tend to be just 2C hotter than LED, and we correct this with warmer rooms. We warm the room, and total water usage gets back on track.
What we don't see in this, is where the transpiration on the plant occurs. We do know though, that the HID bud was only 2C hotter, because it was sweating like hell to keep cool. The picture of water redistribution isn't a big leap to guess. If we then align this, with the bud redistribution on LED plants, we start to see a picture. It's about where the feed was going with HID, and where it's going with LED.
HID tended to give fewer buds, but they were more impressive to look at. I'm finding the pinnacle bud from each crop, shows a similar distribution. LED giving more of that 80% as good, but somehow the few outstanding bits, are fewer.

This is in part, why I'm heating with a radiant heat source. This HID heat, tends to warm the buds, as much of it is radiant heat. It travels like light does. It can't be sucked away by a fan. Also the HID produces things like strong 730nm, which we know plants use, but isn't counted as useful light. The 730nm HID produces, is classified as waste, when looking at efficiency. Same with an LED fixture that uses 730nm LED's. They don't count towards PAR light. Though in recent times we have started to talk about ePAR or extended-PAR. Where we count light to 750nm as useful. It gets a bit of a grey area, open to interpretation if specifics are not outlined well. The HID obviously continues right past 840nm into nothing but heat. But I feel warming the top buds, to see the feed getting to them more, is pretty much as nature intended. Plus it heats my tops better than using my heating system. As my home heating makes easily extracted hot air, that's 28c if I was lucky. While the same power sent to a radiant source over my buds, heats them without being vacuumed away. It;s more efficient.
For relative examples, we could look at outdoor heaters. A bonfire is bloody hot, because you get the radiant heat from it. The air it heats, actually goes straight up. You can see it go, as it carries to much dust. We just call it the smoke. Hot air is just up and away, but radiant heat travels like light. The patio heater is the same, or the marquee for smokers at the pub. They don't waste money heating air that will be instantly gone. To heat you, they must use a radiant source. This is why in our windy tents, a radiant heat source is good at heating the buds.
For me, I have 19c from the home, heated at intake to about 24, then the HID to warm the buds. This is more efficient than a 28c intake temp.
If you live elsewhere, you may have 28c entering the home, so LED alone is perfect.

This is why I use hid lighting with air cooled hoods. I’ve grown in a non heated garage with 0* ambient temps without issue.

 

[Hiddenjems]

Fwiw I’ve heated my entire home all winter with nothing but hid lights.