DIY LED grow lights experiences

green surfer said:

Hey SDS,

For vegging, the spectrum I used with the GG was nice and worked fine.

Usually i'm using for veg: 1royal blue/1 coolwhite around 6000K (for CRI and blue)/3 red 625 or 660 (660 LH CP7P is better because more efficient and its efficiency decrease less with temperature than 625; and the 625 LR CP7P peak is narrower). 3 coolwhites/3 red 660 is fine too, but the coolwhites are a waste of energy for vegging, they are just fine for CRI. Blue/red works fine but i don't like a purplish spectrum, i can't see the green and the health of my plants.

I'm using this 1RB/1CW/3R spectrum for veg, seedlings and cuttings since 4 years and i will never change it, except for a grow with a versatile engine as this last one.

So yes, your 8WW/4LH was lacking of blue for veg.




yes, it makes sence, the plants needs to cool her leaves, so she will increase perspiration with an higher leaf area.

Just a thing:


imao, colder water is in bottom, not in top soil.



not storing more water imao, but increasing perspiration to cool her leaves.

This is a fact that the blue/red ratio influence the stretching or the branching, or the rooting.



MJ grown outside is often leafier than indoor MJ and bud quality is better. There is often a debate about the lightings MH against HPS. Even about blue enhanced HPS vs straight HPS.



for sure it will work great for veg too. Oslon CC is an high IRC led, 95CRI, that means very high cyan/green/yellow in the spectrum. The 2700K KR is 89lm @25°C @350mA, the 4000K KT is 104lm @25°C @350mA, certainly the spectrum will be very vast, but a lot of energy will go to cyan/green/yellow photons, and those wavelength are only useful for our plants when the light intensity is very high (as for HPS), because at high intensity the photons can cross the leaf and be used. So at present i think that if we use high green/yellow light, it must be with very efficient emitters (HPS has high yellow content in spectrum and plants use it for flowering, HPS 600W is around 160lm/W). And personally i think that OSLON CC has not enough efficiency. The spectrum I'm trying to build is blue (but it must be measured well), yellow/amber/red/hyper red and a hint of deep red and far red (so I need absolutely Warmwhite).

I had very good results with the 3NW4000K rebel ES/4reds spectrum, and 3x4500K/4reds, the plants were not especially leafy but yield could be improved i think. The think i don't like (maybe i'm wrong) is that in neutral white there is a lot of green. I tried two lamps with 3NW/4R, both had lenses (55° and 62°), so intensity of light was very high. I had apical chlorosis at 18cm from light! I used very high efficiency neutral whites, around 140lm @350mA 25°C.

Veg and bloom phase have a diffrent photoperiod, 18/6 and 12/12, so this is logical to have two spaces, so logical to have 2 lamps. So i'm searching for a bloom spectrum working fine for all strains. At present, the example is the HPS, so i'm trying to reproduce HPS spectrum, with an high efficiency, without reflector losses, and add 660nm to it and maybe some royal blue, but how much 660 and how much 450 to make a light available for all strains?

It seems that sativas loves a bit of blue and that indicas don't like it (it's logical because of the natural sun light is different under the tropics and under northern latitudes. But we mostly grow hybrids!

I will always prefer efficiency VS spectrum anyway, but when we see the reactions of plants to blue light in bloom phase, spectrum seems to be important too.

One last thing about blue:

because i'm growing in a cool place, I used more blue in spectrum to increase perspiration. Plant metabolism is related to perspiration. But it maybe it could be better to use infrared. Warmwhites will give some far red and infrared. I'm almost sure that the future of led lighting is very efficient warmwhite leds, with nothing else.

Anyway i will try a 3WW/1R/3HR spectrum, with very low blue, we will see. But unfortunately i didn't kept a GG mother.

I apologize for my english! it is hard for me, i can't say half the things i would like to say.

grtz

Click to expand...

Fonzarelli said:

I've been running HPS1000w+630/660nm red led 128w and getting some major density. But I still initiate flowering with more blue(MH) because the plants are still requiring chlorophyll to produce leaves in order to bud later. I try to time it so that I switch to the HPS/red spectrum when they stop "growing" veg leaves for the most part.

The blue light I had on during the last half of budding didn't seem to do anything but heat the area up more so I shut it off and got a huge yield. It's possible they lost some flavor, but they seemed to finish faster and tighter.

I like your NW/red/dr spectrum BECAUSE the NW have a hefty amount of deep blue. I think it works well for low watt conditions.

I don't think the WW will work better because of insufficient blue."

Click to expand...

Overall I'm willing to bet that there is more blue overall in a 400w HPS than 400w of WW led. Is there a way to find out?

Click to expand...

HPS have very little CYAN where as WW LEDs have a lot therefore the led requires less blue light overall to balance the spectrum to whatever kelvin range.

In other words I don't like WW LEDs because they are high in CYAN and seems like wasted watts.

Still will be nice to see the outcome.

Click to expand...

• I still think the use of near UV is a better choice than 450nm blue for flavor/resin production because it does not effect the spectral balance of a red heavy spectrum.​
  
  

Click to expand...

stardustsailor said:

Question #1 :

View attachment 2657992.....

Highest RQE for blue range is ~0.76 at ~430 mm
Green has ~0.87 at 550 nm ....


The few blue photons that reach the leaves -from Sun -,are mostly absorbed from photoprotective pigments .
Not by chlorophylls ...
Magnesium atoms (inside chlorophyll molecules ) " like " more the -low energy but abundant red photons ...
Simple atomic chemistry ....
A really small number of blue photons goes for PS .And they do have poor efficiency .

So why blue at veg ?

Why more than 5-10 %



Question #2 :

MH vegs better than HPS ...
Is it because of more blue or is it because of less reds and Far reds ?
Or because of it's "smoother " better distributed spectrum ,than of HPS ?
Cause vegging with HPS ,causes only stretching and nothing more ...
No less branching ,no less rooting ,no less leaves .....
Not something really noticeable ...
Everything is almost identical ,but the internodal distance ....
So ...
Is it because of more blue or less reds ?
Or both ?

Click to expand...

Fonzarelli said:

An over abundance of red light will also stunt plants. An over abundance of blue light will not on the other hand. I'm talking 460nm and lower.

Click to expand...

Fonzarelli said:

I waited not 1 minute when I made my post before I edited it and you already had replied to my non-edited post. LOL

Not sure how a guy can be wired into the internet to such an extreme degree but whatever.

Easy ...
-Computers are everywhere .Literally speaking.
-I'm kinda in "tight" economic situations.Not many "exits " ....
-There's no girlfriend around ..(at least for time being ) ...
-I "smoke" a lot..
..
And plenty more

Anyway, my best veg results have come from 2 pure blue T5 lamps mixed with 2 pure blue red lamps. The plants stay extremely short and extremely healthy. I get much better growth under this heavy blue mixture than I do from a 1000w Hortilux blue MH. The main stem is has already turned completely woody after only 2 weeks from seed. They have around 20 nodes stacked in only 12in of height.

Click to expand...

Approx the same , is easily doable with less than 10% at blue range ,with leds ....

I know you can grow with HPS because that's all I used at one time full cycle for hydro growing. Now that I've been using the blue/red t5s I will never go back to HPS for vegging.

One major fail a MH light has is the amount of green light present especially the 1000w Hortilux blue. The green peak in the lamp dominates the spectrum and accounts for nearly 30% of the overall light power.

Green light is good at signaling plants and telling them when to stop growing.

Click to expand...

...A link ?
I totally disaggree on that ....

You mentioned that you think it's blue light that's responsible for slowed growth in winter, but it's actually the amount of green light present relative to the rest of the spectrum.

Click to expand...

At winter ?
Green light at winter ?

An over abundance of red light will also stunt plants. An over abundance of blue light will not on the other hand. I'm talking 460nm and lower.

Click to expand...

An over abundance of blue light 460nm and lower will fry the plants .Period .
Simple Physics and Plant Biology .
From ~280 nm up to ~400 nm overall power density of sunlight (noon,tropics ) is ~ 5 Watts per square meter .
When the power of 400-700 nm range is ~400 Watts (~2000 umol/sec ) .

Blue light along with UV is known to boost flavonoids, etc. It's the essence of the plant world.

Click to expand...

Agreed .Through plant's defence (photo-protection) mechanisms ....
Anti-oxidants ,waxes,resins ,etc ....
Plants trying to protect themselves from UV radiation .Affects greatly yields and plant mass .
Great example ,sun grown tomatoes -tasty,delicious,red but small sized - and green house (no uv ) grown tomatoes ...
Great taste of nothing ,no aroma but huge ...Pumped up tomatoes ...Plants didn't have anything (uv ) to protect from ....
But ....A lot remains unknown about effects of UV at plants ....
Little we know ....

For bloom I like to use white light, but only for the blue, 565nm and >590nm.

The amount of green and yellow light needed by plants is almost nil.

Click to expand...

Based on what ?
Hard claim ....
Proofs ,please ....

I say the opposite ....
(*And along with me ,almost every plant biologist .... )

Quantum efficiency is based on the overall amount of photons delivered, not on how much is used or absorbed by plants.

Click to expand...

??????

Don't bother ....

The Quantum yield (quantum efficiency) is variously and rather confusingly defined for photosynthesis
as:

• “The number of photochemical products” [such as moles of CO2 assimilated or O2 evolved] divided by
the “Total number of quanta absorbed”, or

• “The fraction of excited molecules” [i.e., excited by the absorption of a photon] that decay via a
designated pathway [such as via photochemistry, apparently no matter how small the effect produced
per quantum] , or

• The number of times that a defined event occurs per photon absorbed by the system.

So even though the RQE is higher for green light does not mean the plant still uses 98% of the light like it does with blue/red light.

Anyway, some food for thought.

Click to expand...

Green window :

Leaves Absorb all light from ~350 nm up to ~750 nm .Period .Science says so .
Green/cyan range is reflected more from red or blue ,at about ~4% up to 10%.
This detrimental difference allows for the " green window ".

Older leaves or lower leaves or leaves deep in a thick canopy ,receive the green "leftovers " from the rest of the canopy .
They do photosynthesize with those cyan-green-yellow photons ,at ~85 % average efficiency ....
..........

Meaning


The number of photochemical products : set to 100 ....

“Total number of quanta absorbed = 100 / 0.85 = 117.64 green photons

For 100 glucose (example) molecules 117.64 green photons are needed .....

Efficiency of blue at ~430 ..0.76 ..

For 100 glucose molecules 100/ 0.76 =131.57 blue 430 nm photons are needed ......

The plant needs less green photons than blue ones to produce same amount of energy/mass ...

Green window ....


Once more (it became my favourite ....) :

http://www.heliospectra.com/sites/www.heliospectra.com/files/field_page_attachments/what_light_do_plants_need_2012-10-05.pdf

Click to expand...

Click to expand...

stardustsailor said:

internodal distance ....
So ...
Is it because of more blue or less reds ?
Or both ?

Click to expand...

green surfer said:

interesting guys, I have not enough time for a complete answer but:



i do agree, but it is not easy to find 80° UV emitters + good efficiency, anyway i don't need super potent weed.

I'm trying a skunk#1 under (@700mA) 1RB/2WWXTE2900K/1R/3HR for vegging and for the 2-3 first weeks of 12/12, after that i will change the spectrum to 3XTEs/1R/3HR.

View attachment 2658536

and i'm tryind an autoflower (thunder bloody mary, mazarxwhite dwarf) straight under 3WWXTE2900K/1R/3HR @450mA, she is vegging very well, the growth is amazing, look how she grew

here at the first day under this spectrum
View attachment 2658538View attachment 2658539

and 4! days after, no stretch
View attachment 2658540

here are 2 C99, just before harvest, grown under 1RB/2WW3200K XTES/2R/2HR (same spectrum as the GG)
View attachment 2658541View attachment 2658542View attachment 2658543View attachment 2658548View attachment 2658549
total power 36W fans included, C99 FS, 10inches diameter pots. They react better than the GG, but the GG had very low temps during the grow.

Click to expand...

PSUAGRO. said:

Felt the same about the Horti blue 400w, almost the same effect as running an hps! I couldn't understand what the issue was, and was pissed that I spent $90. The BD fems where way more compact under the 330w allstart , which is more red leaning than the Horti. So I agree with you that the green spike COULD be the issue, and will cause stretching. A flowering LED panel with NO 660nm is a mistake IMO, you don't just ignore a chlorophyll absorption peak

How are you liking the 860w all-start Fonz? any pic updates in your thread???

Click to expand...