Which Spectral Power Distribution Is Best For Growing (cxb 3590)?

[BGBlue]

Page 8 from the cree manual. Which relative spectral distribution is best for all around growth in veg/flower?

My guess is for the dark red line with the 3000k, 90CRI.

 

[tags420]

Page 8 from the cree manual. Which relative spectral distribution is best for all around growth in veg/flower?

My guess is for the dark red line with the 3000k, 90CRI.

Common misconception. 3K 80cri is what you want.

In the data sheet it is all made relative to 1. Also known as normalizing graphs. But in reality or "absolute power"...they show the actual output of the different phosphorus conversions and very little if anythign is better about higher CRI.

Through the graph here is for bridgelux spectrum...it shows the loss and gain vs different CRI and spectrums well, and is near identical for cree spectrums.

Here is cree...

 

[BGBlue]

Thank you Tags for the good info and Great graphs.

I see what you mean by having little gain when going for the 90CRI over the 80CRI. Although, it looks like over half of the loss for going for CRI90 is outside the range of photosynthetically usable radiation (below 630nm).

Do you mind explaining where my reasoning is off. Here is what's going through my head.

The reason I believed that CRI90 was superior to CRI80 is because the ratio of usable red:blue light is closer to 1 in CRI 80 vs. CRI 90.
I believe this is good because plant light absorbance of red and blue is close to 1:1

So, I suppose that is the point. The low level of blue-light would be the rate limiting step. In 80CRI and 90CRI the difference in blue output is negligible.

In short, my guess is that anything far above the highest levels of blue radiation is limited because both are needed for a complete photosynthesis cycle.

But now, I just read that PSI and PSII have maxima for absorbance around 680nm and 700nm. So, I suppose I was wrong and red:blue is not best at 1:1.

But then I look at this graph and think, no, a ratio closer to 1:1 is beter.

in fact the image makes me think that heavy blue could be good!

I don't see the advantage of heavy red. In general I think it's all about improving your rate limiting step.

Granted, I am a beginner. And the images I shared is not species specific. However, I am familiar with science/bio/physics (basically two B.S. in both subjects) so, i want to understand whats going on so I can know the lamp I piece together is good. Plus it's fun learning all of this information :)

But yea, CRI90 seems to be closer to 1:1 for R:B color output, based on the normalized graph from their website.

Anyways, I was having trouble finding CRI90 chips so it'll probably have to be CRI80. Even so, I want to understand this.

 

[Toaster79]

Nice explanations about 80 vs. 90 CRI. But what are you gonna choose when you have 3000K and 5000K avaliable both in 90 CRI? Will you choose 5000K for veg and add reds for flower or are you gonna take 3000K and suplement blues in veg and turn them off in flower or whatever?


What I have noticed is that plants don't grow as good in veg under 3000K as under 5000K-6500K and under same spectrum in flower the only difference is the plants under 5000K-6500K are way more frosty with same grow rate.

 

[tags420]

@BGBlue
Another misconception. Mostly driven by bullshit led companies trying to seem like they will owrk. The fact is that there very little difference between any other the colors from 400-700nm.
All those graphs come from taking the individual pigments like chlorophyll a&b and extracting them form the leaves, then mixing them with alcohol...then tested without any interaction from any other pigments or anything from the leaf. None have been used or accepted by the scientific community and never will be.

McCree is the one and only accepted action spectrum. It is an average of 22 species of plants, as well as filed vs indoor grown rates.

595-628nm has the highest efficiency for photosynthesis. Not 660 like many have been perpetuating for so long. There are morphological effects that 660 has...but for pure photosynthetic rates, 595-628nm is the cats meow. And also why hps kills it...there spectrum is not bad actually...but more importantly is pumping out the photons.


@Toaster79
Lower K temps will produce more flower biomass. I have tested it a few times years back with apache lights. Every spectrum they make, even red/blue. The R2, their warmest spectrum, was a clear winner in production and also in potency. Though the potency race was closer, within 1.5%...the yield difference was very evident in each run.

Much of the differences between 3k and 5k comes down to rate of photosynthesis and keeping u with it. 5K and cooler temps will not be as photosynthetically active and at the same time is promoting more direct chlorophyll production. Slower rate + directio green production= seeming to be healthier and growing better.

lower temps like 3k are driving photosynthesis harder and sometimes the plants and growers aren't ready for it and get behind. I still have them stall out when I try and "baby" them a little at the get go. They don't need to be, if anything the opposite.

 

[BGBlue]

@tags420
Awesome. Thanks for the great replies. Very Much appreciated. You know your stuff. I like the drive explanation. I'll read up on McCree

Would you mind helping me figure out which chips to get and how many?

I'd like to bathe the plants and saturate them in light.

I heard you want to max out around (7500 luminous flux)/ (ft^2). I'll have about 4sq. ft.

What I know, from talking to you, is that I want 3000k, and 80cri.

But should I go 2stage or three stage, and how many?

I have the Secret Jardin L90 which is a small tent for the hobbyist. It has a 60cm x 60cm x 135cm flower room, and another room for sprouting/veging/clones which is split into two rooms. 30cm x 60cm x 75cm and 30cm x 60cm x 60cm.

Thanks for the patience, help, and explanations.


@tags420
You know your stuff. What should I read/watch/do to become more knowledgeable? My dream for my hobbyist set up an arduino to keep everything in the sweet spot and log pertinent information. It's not necessary, but it's for meds and having a bit of fun. Plus the optimization game is a fun one to play :)

 

[seaslug]

I bought these for late veg and flowering: 72Vf, 3000K, 80CRI, 4 step (2 step is tighter white quality for architects and such).
CXB3590-0000-000R0HCB30G

A little off topic but I can't find a SPD for my CXA3590 2700K: CXA3590-0000-000R00AD27F

 

[REALSTYLES]

I'm still learning but I've made 13 panels in the last 5 months and waiting for 6 more heat sinks that will be here tomorrow and 80CRI is very good on the CXB's

It's a mix of CXA and CXB 3590's 3000k and 3500k

 

[testiclees]

@tags420

Hey man, i drifted over to this thread by researching photo red/ far red. I'm finishing up a build that has 4 vero29 4k and 4cree 3590s 3500k. Im using .700mA driver on 2 of the panels and ive got spare volts. Ive been asking around if folks thought there was much to be gained by adding some stars.

Appreciate any thoughts.

 

[tags420]

@tags420

Hey man, i drifted over to this thread by researching photo red/ far red. I'm finishing up a build that has 4 vero29 4k and 4cree 3590s 3500k. Im using .700mA driver on 2 of the panels and ive got spare volts. Ive been asking around if folks thought there was much to be gained by adding some stars.

Appreciate any thoughts.

From what I saw over there they covered it all pretty good.
I shoot for ~15% blue range(400-500) and >40% red range(600-700). Speaking in cree spd...3k needs more blue and 4K needs more red.
Vero's run a tad warmer in spd per K temp.

And you already have a mix that will ring in at ~3600K probably. Pretty good. UV tubes would be the most beneficial actually. If I remember your looking for more bag appeal not so much more light for yield. Right?

Just for the last 2-1/2 to 3 weeks and they make a solid difference in the frost.

 

[testiclees]

Thanks bro,

I grabbed an arcadiab t5, 54w uvb. It hasnt arrived yet. Any experience with these, distance, length of exposure?

 

[Flax]

I shoot for ~15% blue range(400-500) and >40% red range(600-700). Speaking in cree spd...3k needs more blue and 4K needs more red.

Since I did not see CXB3590 3500k mentioned I thought I would share some info for you all.

Got the numbers from and threw them into a spreadsheet for a visual comparison.
Unfortunately all they had numbers for were 3000, 3500, 4000 and 5700k.
Keep in mind they measured from less than 8 inches.

A simple comparison of each cob's PPFD output.

A simple comparison of wavelength groups by percentage.

The 3500k has 14% blue and 43% red.

So tags, is the 3500k your sweet spot for flowering?

tia

 

[mike hunt]

3500K is the sweet spot

 

[Flax]

Would a simplistic description be that reds add yield and blues add potency?

If so, would flowering under say a 3500k to start and then a 5700k (has twice the blue but less red) to finish be beneficial?

tia

 

[hybridcheef]

Would a simplistic description be that reds add yield and blues add potency?

If so, would flowering under say a 3500k to start and then a 5700k (has twice the blue but less red) to finish be beneficial?

tia

why would you veg with a red spectrum? and finish with a blue? its just the opposite, dude your ass backwards, what you said about the yield and potency is opposite. blue is grow, red is flower. everyone knows that

 

[sixstring]

why would you veg with a red spectrum? and finish with a blue? its just the opposite, dude your ass backwards, what you said about the yield and potency is opposite. blue is grow, red is flower. everyone knows that

generally yes red flower ,blue veg.but theres lots of growers who will swap out their hps in the last weeks of flower for metal halide to finish the crops off. but your answering a post from 14 months ago,im guessing the plants are done now haha.

 

[hybridcheef]

generally yes red flower ,blue veg.but theres lots of growers who will swap out their hps in the last weeks of flower for metal halide to finish the crops off. but your answering a post from 14 months ago,im guessing the plants are done now haha.

A okay. yea i didnt realize it was an old thread. my bad

 

[sixstring]

we've all done it lol

 

[AvidLerner]

Thank you Tags for the good info and Great graphs.

I see what you mean by having little gain when going for the 90CRI over the 80CRI. Although, it looks like over half of the loss for going for CRI90 is outside the range of photosynthetically usable radiation (below 630nm).

Do you mind explaining where my reasoning is off. Here is what's going through my head.

The reason I believed that CRI90 was superior to CRI80 is because the ratio of usable red:blue light is closer to 1 in CRI 80 vs. CRI 90.
I believe this is good because plant light absorbance of red and blue is close to 1:1

So, I suppose that is the point. The low level of blue-light would be the rate limiting step. In 80CRI and 90CRI the difference in blue output is negligible.

In short, my guess is that anything far above the highest levels of blue radiation is limited because both are needed for a complete photosynthesis cycle.

But now, I just read that PSI and PSII have maxima for absorbance around 680nm and 700nm. So, I suppose I was wrong and red:blue is not best at 1:1.

But then I look at this graph and think, no, a ratio closer to 1:1 is beter.

in fact the image makes me think that heavy blue could be good!

I don't see the advantage of heavy red. In general I think it's all about improving your rate limiting step.

Granted, I am a beginner. And the images I shared is not species specific. However, I am familiar with science/bio/physics (basically two B.S. in both subjects) so, i want to understand whats going on so I can know the lamp I piece together is good. Plus it's fun learning all of this information :)

But yea, CRI90 seems to be closer to 1:1 for R:B color output, based on the normalized graph from their website.

Anyways, I was having trouble finding CRI90 chips so it'll probably have to be CRI80. Even so, I want to understand this.

The 2700K mixed with the 3500k will give you what you are looking for. the 2700 has more red and you can add 6500k for more blue and balance. I would go with 2700K and 6500K mixed in one fixture with 80 or 90 cri.