Is it the light or nutrients?

cobshopgrow said:

haha, yes, your sylvnia example was clearly the exeption of the rule .
HIDs are better the these ancient tech leds for sure,
while you may wonder how little you need to invest in LEDs nowadays to beat a HPS.
it is more money at first, but you save a lot on electricity and running costs later.
above 30cent a kwh and 3 bulbs later thingscould look different pricewise.
HPS is a safe bet to grow some weed with little upfront investment.

Click to expand...

one of the main reasons I don't invest in state of the art technology is IF something goes south there's less loss from hardware the cops confiscate.

But I could DIY a strip panel but I would need to get myself more into hardware specs but that's the "dry stuff" I kinda find hard reading about. Like, how much current to run through diodes etc.. but it stays on my list of things to do at some time....

cobshopgrow said:

dont think so, i veg under low intensity much blue light conditions with 20W on 2 CXB3590 .
not saying its optimal, the 6500 where simply a quite efficient bin at that time.
while it works and will have much more blue to red light in relation to the OPs light which seems to be better in heating then producing light btw.

6500K
View attachment 4592063

Click to expand...

You grow in 100% perlite? How do you water them?

Kassiopeija said:

ok so that lamp isn't that bad spectrum-wise but I suspect ridicuously overprized and may come with outdated tech...

Click to expand...

That “lamp” IS really bad spectrum-wise .Seems that plenty of folks nowdays in the LED section think or believe that light quantity is of more
importance than of light quality.

But is light quality that “shapes”
( photomorphogenesis ) the plant accordingly ,in order to use as efficiently as possible the available light quantity.
Under a bad spectrum ,growth will be far inferior than ideal ,no matter the given PPF to the plants.

(...)plant growth was clearly more closely linked to the spectral fit of the light to the maximum photosynthetic response recorded by McCree (1972) than to PPF or illuminance(...)


(...)Controlling spectral qualities of the irradiation applied enables faster growth or higher yield at a given radiation energy(...)

SDS_GR said:

That “lamp” IS really bad spectrum-wise .Seems that plenty of folks nowdays in the LED section think or believe that light quantity is of more
importance than of light quality.

But is light quality that “shapes”
( photomorphogenesis ) the plant accordingly ,in order to use as efficiently as possible the available light quantity.
Under a bad spectrum ,growth will be far inferior than ideal ,no matter the given PPF to the plants.

(...)plant growth was clearly more closely linked to the spectral fit of the light to the maximum photosynthetic response recorded by McCree (1972) than to PPF or illuminance(...)

https://www.researchgate.net/publication/316473011_Effect_of_the_Spectral_Quality_and_Intensity_of_Light-emitting_Diodes_on_Several_Horticultural_Crops

(...)Controlling spectral qualities of the irradiation applied enables faster growth or higher yield at a given radiation energy(...)

Effects of Light Quality on Growth of Crop Plants under Artificial Lighting

Download Citation | Effects of Light Quality on Growth of Crop Plants under Artificial Lighting | Major light factors affecting plant growth are light quality, light intensity, photoperiod, and the day/night cycle. These parameters can be... | Find, read and cite all the research you need on...

www.researchgate.net

Click to expand...

ok so could you please show me a spectral diagram of a light you do consider good or optimal for dicots?

because it seems like a mis-understanding to me here... Im actually argueing on behalf of spectrum (and not intensity) yet your reply seems to assume the opposite....(?!)

And since we have no spectral sheet (or else) of this light all we can go is by the distribution of the various diodes there... so the idea of them is fine, its just that they are not very efficient... so IN FACT this light isnt a very EFFICIENT photon converter but spectrum-wise is still better than the typical only red n blue blurple.

Kassiopeija said:

ok so could you please show me a spectral diagram of a light you do consider good or optimal for dicots?

Click to expand...

The McCree curve is the ideal output SPD for a general use horticultural light.

Kassiopeija said:

because it seems like a mis-understanding to me here... Im actually argueing on behalf of spectrum (and not intensity) yet your reply seems to assume the opposite....(?!)

Click to expand...

Oh ,I’m really sorry,some of my notes/comments were not directed towards you .I quoted your post mostly to emphasise that the spectrum of the lamp is bad.
We are mostly on the same boat
for more than light quality,you & me.
My bad , if you’ve understood otherwise.

Kassiopeija said:

And since we have no spectral sheet (or else) of this light all we can go is by the distribution of the various diodes there... so the idea of them is fine, its just that they are not very efficient... so IN FACT this light isnt a very EFFICIENT photon converter but spectrum-wise is still better than the typical only red n blue blurple.

Click to expand...

I do not think that we really need a spectral sheet ,to figure out how bad the spectrum of the lamp is .

17x Blue LEDs vs 38x Red ones is
about an output power ratio R:B of 1:1 .Add also the high energy photons from the near-UV LED and the blue portion of the two cool whites.
The amount of green light from the latter is negligible in relation to
the total amount of blue light.

As for the two FR LEDs won’t aid at all ,at any aspect.

You could have 10 more of these fixtures hanging and still the plants would not look better .I bet that
on the contrary ,the plants would have had a much worse health and appearance under higher intensities
of this far-from-ideal output spectrum.

SDS_GR said:

The McCree curve is the ideal output SPD for a general use horticultural light.

Click to expand...

this is a common myth still prevalent because it lasted so long.

all the McCree experiments were flawed because at the time they didnt know that PAR is much well beyond 400-700nm.

Read up on the Emerson-effect and how low-energy photons can excite PS 1. Bugbee actually explains it very well in his vids...

The basic problem with McCree was that he made experiments with artificial light falsely assuming photosynthesis is a 1-step process.

FR has long been considered a minimal input in photosynthesis. In the early 1970’s, PhD physicist and soil crop professor Dr. Keith J. McCree lobbied for a standard definition of photosynthetically active radiation (PAR: λ=400-700 nm) which did not include FR. More recently, scientists have provided evidence that a broader spectrum called photo-biologically active radiation (PBAR: λ=280-800 nm) is more applicable terminology. This range of wavelengths not only includes FR, but also UV-A and UV-B. The Emerson Effect established that the rate of photosynthesis in red and green algae was higher when exposed to R and FR than the sum of the two individually. This research laid the ground work for the elucidation of the dual photosystems in plants. Photosystem I (PSI) and photosystem II (PSII) work synergistically; through photochemical processes PSII transports electrons to PSI. Any imbalance between R and FR leads to unequal excitation between PSI and PSII, thereby reducing the efficiency of photochemistry.

SDS_GR said:

That “lamp” IS really bad spectrum-wise .Seems that plenty of folks nowdays in the LED section think or believe that light quantity is of more
importance than of light quality.

But is light quality that “shapes”
( photomorphogenesis ) the plant accordingly ,in order to use as efficiently as possible the available light quantity.
Under a bad spectrum ,growth will be far inferior than ideal ,no matter the given PPF to the plants.

(...)plant growth was clearly more closely linked to the spectral fit of the light to the maximum photosynthetic response recorded by McCree (1972) than to PPF or illuminance(...)

https://www.researchgate.net/publication/316473011_Effect_of_the_Spectral_Quality_and_Intensity_of_Light-emitting_Diodes_on_Several_Horticultural_Crops

(...)Controlling spectral qualities of the irradiation applied enables faster growth or higher yield at a given radiation energy(...)

Effects of Light Quality on Growth of Crop Plants under Artificial Lighting

Download Citation | Effects of Light Quality on Growth of Crop Plants under Artificial Lighting | Major light factors affecting plant growth are light quality, light intensity, photoperiod, and the day/night cycle. These parameters can be... | Find, read and cite all the research you need on...

www.researchgate.net

Click to expand...

yes the lamp is probably also really bad spectrum wise, still the spectrum isnt his main problem.
he just have a good 100 PPFD, what flowers will you expect? even if you give the 100ppfd in a optimal or at least better spectrum.
you can see many grow reports here people using blurple leds with their veg and bloom switches turned to on and no to little green.
cheap blurples do grow weed and if you burn enough watts even big buds.
can your weed grow better, yes
can you influnece the plant shape and other parameters, yes
but the OP isnt after plant shape,or optimizing the last 10%, his plant needs photons and the blue portion or the uva led isnt his problem.

cobshopgrow said:

yes the lamp is probably also really bad spectrum wise, still the spectrum isnt his main problem.
he just have a good 100 PPFD, what flowers will you expect? even if you give the 100ppfd in a optimal or at least better spectrum.
you can see many grow reports here people using blurple leds with their veg and bloom switches turned to on and no to little green.
cheap blurples do grow weed and if you burn enough watts even big buds.
can your weed grow better, yes
can you influnece the plant shape and other parameters, yes
but the OP isnt after plant shape,or optimizing the last 10%, his plant needs photons and the blue portion or the uva led isnt his problem.

Click to expand...

I have also seen a grow somewhere here with some amazon blurple, but the growth in the picture posted was beautiful. Wish I could find it, remember liking the post.