Umol goals

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Brooks530

New member

• Jan 19, 2018

• #1

Hey guys,


First post and I am looking for some information on target umol numbers. I will be growing mainly indica plants and have been trying to find more information on target umol ranges per day. I have gathered that flowering between 700-900 is the optimum level. I aim to achieve this with the Fluence Spydrx Plus lights. If anyone has experience with these lights or umol information for both Sativa and Indica please respond!

 

Bobby Boucher

Active member

• Jan 20, 2018

• #2

I always read "more is better", but was shown firsthand to keep things ~35w hps per square foot while growing sativas, 1:1 plant:light, hanging the lights high and leaving them there to encourage stretch and utilize vertical space. Just gotta trellis the shit out of 'em to compensate.

Too dunce to convert that to umol, and too dunce to understand how any of this translates into LED's, but 400w for 3x3, 600w for 4x4, 1000w for 5x5 for seems to be the general consensus, for sativas anyways.

 

Phaeton

Speed of Dark

Veteran

• Jan 20, 2018

• #3

Generalities and averages is all I can add.

When using grids of CMH as overhead lights, plants got 1000 - 1100 umols and grew well. Light is added from the sides, fluorescent or passive LED bars at 200 - 300 umol.

Using LEDs as overhead lighting the intensity was reduced to 800 - 900 umols with similar results, I am guessing the 200 unneeded umols were the green and yellow. The sidelight requirements remain the same at 200 - 300 umol.

 

coldcanna

Active member

Veteran

• Jan 21, 2018

• #4

watts per square foot is somewhat misleading because you don't consider the quality and evenness of light and how the given hood projects it. i researched this exact subject adnauseam and couldn't find anything published for cannabis specifically so went with information on tomatoes. A daily light integral of 22 is minimum for production but studies indicate that closer to 30 is ideal.

 

DunHav`nFun

Well-known member

• Jan 21, 2018

• #5

Well guys....I`m not sure if what I`ve gotta say will help with OP`s original question on umols since I`m old head schooled with HPS as well as vertical bulbs instead of horizontal lights inside reflectors.....but...

Forever and a day I was taught 50 watts per sq ft to light the room and the plants would respond accordingly with dialed environment and proper nutrient regimen.....that said.....I grew 2 1/2 lb plants with 34 watts per sq ft for a decade but the rooms and strain were dialed.....now....

Once I stopped big plants and went to increased plant numbers , I also upped my wattage to 50 per sq ft , and with the only strain I had that was @ 34 watts for a decade , and outside for at least 12 yrs before that in guerilla grows , the quality flavor and smell were as different as night and day.....and that`s a good thing....lastly....

Figure 35-50 watts per sq ft and find the appropriate umol conversion , dial your environment , and yield accordingly....anyways.....my 2 cents from all those yrs....

Peace.....DHF.....

 

P

paradoxlost

Member

• Jan 25, 2018

• #6

You should be shooting for the same PPFD as the sun which is 2500 PPFD.

Only one light on the market today which can achieve this level of photon density.

 

Lazyman

Overkill is under-rated.

Veteran

• May 19, 2018

• #7

paradoxlost said:

You should be shooting for the same PPFD as the sun which is 2500 PPFD.

Only one light on the market today which can achieve this level of photon density.

Click to expand...

Unfortunately the light quality is far from "apples to apples." If you supply 2500ppfd to your canopy, you will have bleached and burnt tops. I've done it.

2500ppfd works out to a DLI of 108. We found that far better results are achieved at exactly half that number, 1250 equals a DLI of 54 (which is a hair over the recommended 40-50 DLI for cannabis.)

Being able to cool the room effectively and fertigate frequently allow this elevated DLI to not damage flowers and terpenes, but higher levels definitely do.

 

DunHav`nFun

Well-known member

• May 19, 2018

• #8

Lazyman said:

Unfortunately the light quality is far from "apples to apples." If you supply 2500ppfd to your canopy, you will have bleached and burnt tops. I've done it.

2500ppfd works out to a DLI of 108. We found that far better results are achieved at exactly half that number, 1250 equals a DLI of 54 (which is a hair over the recommended 40-50 DLI for cannabis.)

Being able to cool the room effectively and fertigate frequently allow this elevated DLI to not damage flowers and terpenes, but higher levels definitely do.

Click to expand...

Hey Lazyman.......What`s that 1250 ppfd convert to in watts per sq ft......and.....What`s the 40-50 daily light integral.....40-50 what ?.....

Educate an old fart as to how this umol and ppfd par shit`s any different from 35-50 watts per sq ft ....

Thanks bro.....just tryin ta learn ......

Peace.....DHF..........

 

Koondense

Well-known member

Veteran

• May 19, 2018

• #9

Hey DHF, got you a link
https://en.wikipedia.org/wiki/Daily_light_integral


Cheers

 

Lazyman

Overkill is under-rated.

Veteran

• May 19, 2018

• #10

DunHav`nFun said:

Hey Lazyman.......What`s that 1250 ppfd convert to in watts per sq ft......and.....What`s the 40-50 daily light integral.....40-50 what ?.....

Educate an old fart as to how this umol and ppfd par shit`s any different from 35-50 watts per sq ft ....

Thanks bro.....just tryin ta learn ......

Peace.....DHF..........

Click to expand...

It doesn't translate to wpsf so well as it doesn't factor in distance to the canopy. You multiply your ppfd at the canopy by 3600 (to get minutes per hour) and multiply that x 12 for flowering hours of light. Divide by 10000000 and you should have your daily light Integral. His measures how many PAR photons hit your canopy a day

 

Muleskinner

Active member

Veteran

• May 19, 2018

• #11

FWIW I'm running about 630 umol/sqm of PL Light LED and the result is better than running Gavita HPS at 815 - better penetration and coverage. My lights are pumped up at 460nm and 660nm and it appears to work really well.