Correct Lighting Intensity

[Bobby Smith]

Okay, have searched this site, others, and the Internet in general and am trying to come to a consensus (from people who know) about what the "ideal" amount of lux/footcandles hitting plants would be for flowering.

Setting up a DIY Coliseum grow, which will have four 600s (5 or even 6 in the winter) running down the middle (stacked vertically, either bare bulb or in a cooltube, TBD), and am ordering my light meter off of Ebay.

Going to setup the stacked lights and then take some light measurements at different distances to figure out the best specs for the octagon - don't wanna make it too large and have airy buds, but don't wanna make it too small and waste extra light.

Reading Jorge's Bible, and on page 182 he says that 10,000 foot candles (or 107,500 lux) is the "maximum" light requirements for plants - to anyone's knowledge, has this ever been confirmed/refuted?

I know some people out there have light meters and take readings..........share the knowledge, please.

Thanks,
Bob

 

[l0g1c4l]

IMO you should not necessarily base your work all on jorge...if i were you i would just read as many threads in this forum as you can.

As for you grow area, depending on how you mount your bulbs you will have a maximum grow area and depending on the strain you choose to grow and how long you plan on vegging them for all comes in to play.

 

[Bobby Smith]

IMO you should not necessarily base your work all on jorge...if i were you i would just read as many threads in this forum as you can.

As for you grow area, depending on how you mount your bulbs you will have a maximum grow area and depending on the strain you choose to grow and how long you plan on vegging them for all comes in to play.

Thanks for the reply, but we got our signals crossed somewhere.

I don't rely on Jorge that much (if at all); I feel as though his lighting data is probably a little outdated with the more recent developments in weed growing.

I know how I'm going to mount my bulbs, how long I'm going to veg, the strains, etc. - this isn't my first time growing, just my first time growing vertically in an octagon (DIY Coliseum) that I'll be designing and building.

That being said, the light readings I get when I stack my bulbs will determine how large I can make the diameter of the octagon (and how many plants I can run in there) - so my question to the experienced growers who have taken readings is: What lux do you shoot for when determining light distance from the plant?

Is 100,000 lux a good number? 85K? 115K?

That's what I'm trying to figure out - don't wanna build the octagon too large and lack light intensity, but don't wanna build it too small and hit the plants with more light than they can use efficiently.

Sorry for rambling, I'm high.

 

[Papa]

BS,

direct sunlight in the middle of a summer day is about 10,000 footcandles. that's somewhat accurate, i've measured it.

bare lamp footcandles for 1000w HPS as measured recently by Bossman were:

1000 watt HPS magnetic ballast.
2 ft away 4200 fc
3 ft away 2700 fc

1000 watt HPS digital Global Green House
2 ft away 6630 fc
3 ft away 5000 fc

1000 watt HPS digital Future Bright
2 ft away 5500 fc
3 ft away 3200 fc

which demonstrates quite a range depending on the ballast used . . . and i know from experience that these levels will also vary from other factors, both from lamp to lamp and age of the lamp/ballast, etc.

remember that a number of folks have experienced "lumen shock" from not easing the levels up slowly from veg to flower. if you pop a plant right up to 10,000 footcandles it goes into shock.






Papa

 

[ga213]

what about PAR, why does no one talk about this?

 

[pikes peak 69]

I tried to make a post just before you and computer locked up.
I was talking about watts per sq ft and par.
I know that the general consenses is you want about 50 watts per sq ft. ideally. Up to about 70 wpsf you may see some gain, after that it becomes more of a "cost in vs product returned" type of situation.
As far as par, I never learned the numbers but more growers look at par then most other things when it comes to choosing bulbs or layout of a room.
I agree with ga213, what about par, anyone?

pp69

what about PAR, why does no one talk about this?

 

[Bobby Smith]

BS,

direct sunlight in the middle of a summer day is about 10,000 footcandles. that's somewhat accurate, i've measured it.

bare lamp footcandles for 1000w HPS as measured recently by Bossman were:

1000 watt HPS magnetic ballast.
2 ft away 4200 fc
3 ft away 2700 fc

1000 watt HPS digital Global Green House
2 ft away 6630 fc
3 ft away 5000 fc

1000 watt HPS digital Future Bright
2 ft away 5500 fc
3 ft away 3200 fc

which demonstrates quite a range depending on the ballast used . . . and i know from experience that these levels will also vary from other factors, both from lamp to lamp and age of the lamp/ballast, etc.

remember that a number of folks have experienced "lumen shock" from not easing the levels up slowly from veg to flower. if you pop a plant right up to 10,000 footcandles it goes into shock.






Papa

Thanks Papa, appreciate it.

I (re)found a great thread by Ddoc regarding Coliseum lighting which seemed to shed some light on the situation - basically, 70K lux (`7K foot candles) is the goal to shoot for - anything over that, and Ddoc says that spectrum becomes more important than intensity.

Thanks again.

 

[Seamaiden]

what about PAR, why does no one talk about this?

Because it's expensive to measure and many folks have some difficulty wrapping their heads around the concept.