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Best colour for cannabis flower only
Posted: Sun Apr 29, 2018 1:41 pm
by FlippyNips
I'm currently vegging under T8s and looking to get an LED set up to purely to flower and use the T8's to veg until I upgrade the veg light to LED.
I can't see myself using the same light for veg and flower so what colour is best for flower only?
I have already got an HLG-240H-36A as it was very cheap and I like the area the QB132 will cover but they are only currently available in 2700k and 4000k. I could wait to see if they get any others in if 3000k or 3500k would be much better.
I would prefer to change my driver than have less than optimal colour.
Thanks for any help.
Re: Best colour for cannabis flower only
Posted: Sun Apr 29, 2018 2:14 pm
by majorana
Anywhere between 2700K and 3500K is generally what people use for flower. Often people go in the range of 3000-4000 for an all-around light, but if flowering is the only use planned for the light 2700K will work great.
(The downside of 2700K in veg is that you'll get a pretty stretchy plant.)
Re: Best colour for cannabis flower only
Posted: Sun Apr 29, 2018 5:14 pm
by LivingLight
2700k led is for sure a very good spectrum for canna flowering.
3500k and higher color temp are not very good at flowering imo
If you are looking for a good all-around spectrum go for a 3000k. Unless you want very small plants for a very small place, the 3000k will grow very well and flower pretty well too. The only downside of the 3000k is that the first 2 weeks would need additional blue to be optimal. But then it's providing good photosynthetic efficiency and decent branching.
Re: Best colour for cannabis flower only
Posted: Wed May 02, 2018 4:14 pm
by unkle_psycho
I'm just having a discussion about this in another thread. I'm used to HPS and now I did a few rounds with a 4500k sulfur plasma. Great for veg but horrific for flowering...
I'm looking at building my first led setup and using bridgelux vesta strips. They have separate channels for 2700k and 5000k. Im thinking of building a light for 2x4 where both color channels have 225w drivers so I can manage with either channel individually, or theoretically have a 3850k light for 4 x 4.
Do you think that 3850k in 90cri is warmer then it sounds? Defiantly feeling more confident about the design since your advising to flower at 3000k or less. First I was planning 150w per channel, but then I could not really go warmer then 3500k during flowering.
Re: Best colour for cannabis flower only
Posted: Fri May 04, 2018 11:29 am
by LivingLight
unkle_psycho wrote: ↑Wed May 02, 2018 4:14 pm
I'm just having a discussion about this in another thread. I'm used to HPS and now I did a few rounds with a 4500k sulfur plasma. Great for veg but horrific for flowering...
I'm looking at building my first led setup and using bridgelux vesta strips. They have separate channels for 2700k and 5000k. Im thinking of building a light for 2x4 where both color channels have 225w drivers so I can manage with either channel individually, or theoretically have a 3850k light for 4 x 4.
Do you think that 3850k in 90cri is warmer then it sounds? Defiantly feeling more confident about the design since your advising to flower at 3000k or less. First I was planning 150w per channel, but then I could not really go warmer then 3500k during flowering.
sulfur plasma isn't it the most expensive lamp ever?
Asking if the 3850k 90CRI is warmer than it sounds, i guess you wwanna know if it's gonna work better than a 3500k 80CRI or something.
It's very hard to considerate every aspect of a spectrum, specially for flowering.
Maybe you'll get the answer with the spectrums
And btw, in my calculator, the vesta full spectrum is given around 3500k. But whatever the colour temp here are the spectrums:
Re: Best colour for cannabis flower only
Posted: Fri May 04, 2018 11:38 am
by tazztone
LivingLight wrote: ↑Fri May 04, 2018 11:29 am
here are the spectrums
for this graph, did you supply each with the same input wattage?
Re: Best colour for cannabis flower only
Posted: Fri May 04, 2018 11:47 am
by LivingLight
tazztone wrote: ↑Fri May 04, 2018 11:38 am
LivingLight wrote: ↑Fri May 04, 2018 11:29 am
here are the spectrums
for this graph, did you supply each with the same input wattage?
The spectrums are normalised at 1 radiant watt
so same light output, i could get a spectrum with same input wattage but then i would need to consider at equal price
Re: Best colour for cannabis flower only
Posted: Fri May 04, 2018 11:52 am
by LivingLight
I think i'm gonna try to calculate for the vesta comparing only 2700k running at 25w to 2700k+5000k running both at 12.5w
to see if it's interesting to run only the 2700k leds for flowering
Re: Best colour for cannabis flower only
Posted: Fri May 04, 2018 12:40 pm
by LivingLight
So, considering the two options for flowering:
-5000k+2700k both running at 1A --> electrical efficiency : 46.5%
-or 2700k only running at 2A --> electrical efficiency : 41.2%
I think i would go for the full 2700k, as the leds are not losing a lot of efficiency running higher.
I don't think the higher blue light amount with the full spectrum could be really beneficial. It could even be the opposite
Re: Best colour for cannabis flower only
Posted: Fri May 04, 2018 12:48 pm
by tazztone
you could however lose more efficiency because each led is getting hotter. and 2A is at rated maximum current.
on the other hand, would you also suggest running 5000K-only in veg stage?
