Spectrum choice?

nachooo

Well-Known Member
Hello, and thanks for reading. I have 6 pure sativas in a 2x3 square foot size and a good reflection. I have used 6 vero 18 cobs at 5000 k 70 cri 100 total watts 16000 lumens aprox for the vegetation phase.

The two first flowering weeks, I used the same leds but I use 200 watts so aprox lumens according to the datasheets were 29000. (to avoid too much stretching cause this strain does it a lot)

The third week of flowering I added 40 more watts in 4 cobs vero 18 3000 80 cri. Aprox 8000 lumens more. So at this moment I have 29000 lumens at 5000k plus 8000 lumens at 3000k total lumens 37000 total watts 240.
Plants are happy and all is going well

From now I have 5 more weeks to come (early sativa) and two posibilities:

1) Keep using the last configuration until the end of flowering

2) Use 100 watts of 5000k cobs...16000 lumens aprox plus 100 watts more of 3000k cobs. This will be according to datasheets about 16000 lumens more (these are 3000k last generation veros...more efficient than the 5000k ones) Total 32000 lumens. watts 200

Resuming:
1) 37000 lumens (29000 5K /70cri) + (8000 3K /80cri)
2) 32000 lumens (16000 5k /70cri) + (16000 3k /80cri)

Also I have the posibility of add 10 to 20 watts of far red 730 nm leds when stretching phase stop.

Which one of the options will be the better in your opinion? and..will the add of far reds change the posibilities?

Thanks for your attention and best regards from the spanish Pyrenees.
 

GreenLogician

Well-Known Member
Hmmm, going by old MH and HPS theory, I'd say that's too much high k light, to swap some out for more 3k.
But, you say that your configuration for lower average k, is about 5/37ths less luminous in total?
Hmmmmmm. I don't know :)
 

HydoDan

Well-Known Member
I would do that..but I have only two 100 watt drivers and two 20 watt drivers... 6 5000k cobs and 4 3000k cobs...considering the way the lamps are done...these are the two main posibilities....
I would start with #2 for a good spectrum and less lumens. See how it goes... Maybe change it up if necessary..
It's all a learning experience!
 

nachooo

Well-Known Member
Probably I will do that..Have to say that I calculate bad the lumens..instead of 8000 should be 7200...
 

MeGaKiLlErMaN

Well-Known Member
3500k 90CRI is the best option for most fixtures. Has far red built in and has the second highest par output while still not making plants stretch as much.
 

nachooo

Well-Known Member
3500k 90CRI is the best option for most fixtures. Has far red built in and has the second highest par output while still not making plants stretch as much.
I have also reach this conclusion after reading lots of post...next cobs I will buy will be that, unless consensus change... Also I am following quantum boards.... But at the moment I have to work with the cobs I have.
My only problem with far red is stretching in early flowering phase...I can overcome this...but...the real problem comes with smell...plants smell much more...
 

MeGaKiLlErMaN

Well-Known Member
I have also reach this conclusion after reading lots of post...next cobs I will buy will be that, unless consensus change... Also I am following quantum boards.... But at the moment I have to work with the cobs I have.
My only problem with far red is stretching in early flowering phase...I can overcome this...but...the real problem comes with smell...plants smell much more...
Smell? Get a carbon filter I prefer phresh
 

MeGaKiLlErMaN

Well-Known Member
Yes...I got a little one ...but I have too much humidity..sometimes about 75-80%...my sativas can cope well this , but carbon filters not...
Dehumidifer is not an option in this place...
Well you need to run that fan 24/7 but if the humidity is still at that level you will get bud rot and that would make a dehumidifier a necessity to save your plants. But hey I've been there. One grow is enough to get you an roi.
 

nachooo

Well-Known Member
Well you need to run that fan 24/7 but if the humidity is still at that level you will get bud rot and that would make a dehumidifier a necessity to save your plants. But hey I've been there. One grow is enough to get you an roi.
Yes..fan is 24 hours on:)
 
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