Noob LED question about Kelvin!

SonsOfAvery

SonsOfAvery

Well-Known Member
I'm now confused about Kelvin when considering a cob or QB DIY build.
I realise that I risk sounding like a total idiot here, but hopefully someone with the right knowledge can explain.
In almost every piece of information I've read regarding growing it states something like 5000-6500k for veg and then 3000-3500k for flower.(roughly).
But when it comes to cobs or quantum boards I see a lot of people going with 3500k or 4000k for the full grow. Why is this?
Surely this will cause the plants to stretch a bit during veg?
Thanks in advance for any information.
 
MonkeyPickAss

MonkeyPickAss

Well-Known Member
It will indeed cause a little more stretching but it's a compromise. 3500k is the best solution for a grower who only wants one set of lights for both veg and flower. I have a separate veg setup that's about 1/3 the power of my flower setup. I do 4000k for veg and 3000k for flower.
 
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Nugachino

Nugachino

Well-Known Member
If you were to look at the graphs of these cobs. You would find that 5000k is very blue and has very little red in it. 4000k is almost an even balance of red and blue outputs. And 3500k has a much smaller peak of blue than it does of the red.

Having said that. The 3500k chips have enough blue in them to get through vegetation cycle without needing to supplement with another, more blue cob/globe. It's in the flower stage that the 3500k chips really excel. The added red is supposed to help speed along flowering.

I'm too new a grower to really comment on the validity of such claims. But, I will say. My plants are doing quite well under these Vero29 cobs. 3 weeks into flower. And they've spread out a little further into the mesh. And the buds do seem to be developing rather nicely. All in all. They are money well spent. Much better than my pissant little 90w blurple I got for the same price.
 
420Barista

420Barista

Well-Known Member
SonsOfAvery said:
I'm now confused about Kelvin when considering a cob or QB DIY build.
I realise that I risk sounding like a total idiot here, but hopefully someone with the right knowledge can explain.
In almost every piece of information I've read regarding growing it states something like 5000-6500k for veg and then 3000-3500k for flower.(roughly).
But when it comes to cobs or quantum boards I see a lot of people going with 3500k or 4000k for the full grow. Why is this?
Surely this will cause the plants to stretch a bit during veg?
Thanks in advance for any information.
Click to expand...
you got the info correct on veg and flower spectrums.
as for why people are using 3500k-4000k for a full grow I can fathom is COST
with an led fixture if your growing for yourself alot of growers will buy one fixture to fit the grow space or tent.
in the past with HID lighting veg was with a MH bulb(s) and when it came time to flower you swapped out the bulb with a HPS and were good to go
so the cost was an additional bulb, led fixtures arent as cheap as a hid bulb so many growers will get a 3000k led fixture and use it for both veg and flower

if your running a few tents then go with a 5000k fixture for veg tent and 3000k for each flower tent
 
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