calvin.m16
Well-Known Member
HPS VS LED in my mind
vs 
vs 
vs vs 
Study finds HPS spectrum results in higher photosynthesis rate (per light quanta) than LED spectra
- Thread starter Kassiopeija
- Start date
lusidghost
Well-Known Member
Maybe 5 or 6 years ago. Also the truck and the car both get the driver from point A to point B. The truck is just burning way more gas.
I amTHE...GanjaFarmer
Member
Big trucks and old ass HID technology are for guys with little peckers.
Kassiopeija
Well-Known Member
Not sure if I confuse the memory of ur journal now here but if you'd measure PPFD in ur empty bloom room what would the averaged numbers state at (a) your normal canopy max end-height, 30cm deeper & 60cm deeper again?
I'd probably try to put a bunch of high-K 600w MH HIDS in a vertical hood that disperses the light rather to the sides so it mixes more blue to the HPS equally, in like 3:1 ratio HPS:MH
LED:
the most wide spectrum u can find, except for the cheep asian brands that sport 760nm alibi diodes
Accustomization of leaves to high irradiance during their actual growth would also be a thing. Sunleaves have 20-30% less chlorophylls naturally to take less damage from high influx. Can't see how that could be achieved by 400-500 continuous PPFD in 18/6 indoors. LED may offer super nice digital control over these things in the future IF we just could get MORE colours to high efficient output than the usual white n reds ....
Once my little shitters are there I'll be using 300w-500w MH/HPS 2-combo lamp to simulate this 6h MH, 6h MH+HPS, 6h HPS which saves 12h of 150-250w electricity per day, but still gives a long light regiment + a mid-day high irradiance
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Kassiopeija
Well-Known Member
But let's not make this a HPS vs LED thread lol
Kassiopeija
Well-Known Member
for example, this chart is highly informative, even though it shows only a very narrow snapshot of 1 side of the story.
but it's interesting what the addition of 20% yellow to blue & red does, when yellow on its fares actually rather bad.
The RBY recipe is so efficient it depletes in-leaf CO2 albeit having the most open stomatas.
calvin.m16
Well-Known Member
Need a big truck to haul your mom around in. Especially when I'm picking up bales.
Kassiopeija
Well-Known Member
Terran sun vs its radiation in space:
>> you see how the higher blueshifted the light is, the more it gets absorbed by our atmosphere. Which is the reason why when the sun is in zenith its blue aspects are the greatest.
The less filter molecules there are, the harsher it gets
But only a little comes through, but due the sun's physical properties, it may reach everywhere equally at the first incident.
How could that be replicated in artificial light-setups without frying the tops??
edit:
that last pic is interesting to see they didn't pick 315nm arbitrarily as UVA cutoff to UVB but because there the flux rapidly seems to decline/drop.
Milky Weed
Well-Known Member
I knew it, you grow hay!
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Popop
Well-Known Member
How come? Unreliable?
Milky Weed
Well-Known Member
I think he means he was throwing his spent ones under the house.
I amTHE...GanjaFarmer
Member
I got no mom. (Ima test tube baby.) Me and dad have just been sharing yours!
grotbags
Well-Known Member
@Kassiopeija you have probably already seen this, but i thought id post it up anyway.
https://escholarship.mcgill.ca/downloads/7p88cn54p
https://escholarship.mcgill.ca/downloads/7p88cn54p
Kassiopeija
Well-Known Member
nope - thx, reading it
what do you draw out of that thesis?
grotbags
Well-Known Member
i was hoping you would tell me lol...
is the higher dry mass from the hps coming from the better penertration due to the extra green light?, shows spectrum has a definite roll to play and it shouldnt all be about efficiency.
i found the nuitrient uptake of the different spectrums the most interesting. i never really realised just how important spectrum is in driving different nutrient uptake. i think most growers have seen how different spectrums from different light sources can effect nuitrient uptake, but is it not just effecting it, is it actually driving it?.
we know in general a blue shifted spectrum is better for veg and a red shifted spectrum is better for flower, and in veg generally plants need more N to grow leaf and stalk and in flower they need less N and more P and K to grow flowers.
blue heavy spectrums seems to drive N, Ca, Mg uptake, so good for veg, also the heavy blue spectrums seem drive sulfer uptake more, so makes sense with the higher terps numbers and blueing your spectrum out at the end of flower/swapping out sodiums for metal halides for the last week or so for better taste/terps.
the red heavy spectrums seem to drive P, K, uptake more so good for flower growth but not great for thc/terps production ect which ties in with led grown bud(ample blue) generally scoring higher in thc and terps than sodium grown flower(very little blue).
we know uvb light can trigger the uvr8 gene leading to increased thc levels ect, but normal led spectrums contains no uvb or uva yet they still show a bump in thc ect compared to sodium and heavy red spectrums with very little blue. is this down to the more blue in the spectrum the more nutrients that are available that faciltiate better thc, terp production ect...?.
@Kassiopeija do you know how this mechanism works? i know roughly how different nm wavelengths drive the different photosystems and hit different chlorophyll peaks ect, but how is different nm light driving different nutrient uptake?, different protein inducement/suppression?.
or is it just as simple as blue shifted spectrums signal a strong vegative response and red shifted spectrums signal a stronger generative response so the plant naturally consumes more of the nutrients the response demands?. or is that just saying the same thing i already said just in a different way???...
as for leaf and inflorescence colouration im not sure what to draw from it apart from hps and rose had similar rgb levels and both have a very similar blue to red ratio.
amber and red had the highest percent green and both are primarily red heavy with almost no blue and again with a similar blue to red ratio.
purple and blue had the lowest rgb levels and both are heavy blue spectrums but with different blue to red ratios?.
most of this is above my pay grade lol and im bombed and rambling so ill gladly be put in my place when you tell me i have got it all wrong...
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OneHitDone
Well-Known Member
It seems as though you are on the right train of thought.
One other interesting observation I that when talking Blue Light vs Red light spectrums in the HID and Fluorescent realm, nutrient solution composition does not seem to be as touchy. You can run the same formula under T5, MH, and move to HPS with the same solution and not have the wild swings in plant nutrition issues or need for "Cal-Mag bro". I would attribute this to "most" led spectrums still being MUCH narrower than lamp technologies despite the "Full Spectrum" pitch plastered on all of these led systems.
Kassiopeija
Well-Known Member
The study is largely bogus. Other studies on monochromatic LED show you need at least 3 colours for efficient photochemistry.
The writer also ignores the fundamental differences of a bulb that emits light in all directions which creates way better diffuse light and different measurement parametrics when using a non-spherical light absorber for the quantummeter.
The study didnt write down how much raw photons are released per lamp so that puts a huge question mark in the homogenity of the comparison.
If I were to speculate the study tried to investigate into minor details of HPS spec photochemistry - the little blue part emitted. That blue is already enough for photoreceptors to work properly but not enough for photosynthesis. The study now focuses on the photosynthetic properties of various blue to orange ratios, completely ignoreing the far-red aspect with its tremendous effects this has on both photochemistry & other photoreceptors.
So the amber HPS diode replicant spec cannot replicate HPS results at all. The study could have used that spec and further amend with FR, IR & blue and then play around with those relative ratios to optimize results (and thereby HPS spectrum).
But the monochromatic 440+630nm is just a different story, and for more widely accepted comparison of results a 660nm instead of 630 would've been better.
Another basic problem which I see in alot of studies is the low-fluence light setting PAR PPFD ~400 at tops! This is far from the light-saturation point of Cannabis. The plant stays in a light-hungry state and know, excitons are needed for N & S reduction as well.
Thus, any effect mediated via the photoreceptors may be offset or overwritten by a light colours inane ability to promote photosynthesis at that low-light setting. ~~30% of blue photons are screened by carotenoids and that energy never makes it to promote sugar accumulation, so 400ppfd blue is worth like 275ppfd red in that regard. You see that in the studies graphs pretty well...
A better approach to separate photosynthesis from photomorphogenesis is to apply so much light that a higher application doesn't result in a higher net photosynthesis rate (full light saturation in Cannabis starts at 1500umol at 25-30°C 380ppm CO2) and from then onward, the true effect of a light recipe on the shape & morphology can be measured.
These studies already exist and they basically show that the higher irradiance nears itself the LSP the more irrelevant becomes colour in terms of PS rates in an individual leaf.
grotbags
Well-Known Member
i have read before the effect of spectrum on photosynthesis deminishes the higher the intensity of light but not read anything about intensitys effect on morphology.
are you saying theses studys show no effect on morphology via spectrum once you hit light saturation?.