Watts per sq ft. How many watts in your grow space

[Death The Cultivator]

Most of the stoner-way to measure things are kind of useless.

It makes sense, in the north where the light shine 24/0 the light it is less intense than at the equator where it shine 12/12. It also shine less intense during night but it's never dark.


It's different for different species but weed don't need darkness. My opinion is that dark period for autos is nonsense but if I for some reason would want to let the plant rest I would dim it a few hours to simulate night in the far north.

That's the thing though. Everyone has an opinion. At the very least I'd like to pick the brain of a horticulturalist or plant sciences major to have a reasonable discussion.

On one hand we have people basically saying that Ruderalis can metabolize 24/7 whereas science says important processes occur during the dark period. Is Ruderalis really getting 24/0 in it's natural environment or does light spectrum+intensity play a role in the semblance of 24/0 lighting? Is the plant seeing 24/7 light that it can photosynthesize?

 

[Disburped]

That's the thing though. Everyone has an opinion. At the very least I'd like to pick the brain of a horticulturalist or plant sciences major to have a reasonable discussion.

On one hand we have people basically saying that Ruderalis can metabolize 24/7 whereas science says important processes occur during the dark period. Is Ruderalis really getting 24/0 in it's natural environment or does light spectrum+intensity play a role in the semblance of 24/0 lighting? Is the plant seeing 24/7 light that it can photosynthesize?

Oh yes, 24h is natural light regiment for ruderalis but ruderalis is kind of like a broad spectrum of landraces. In the far north the light has less blue, less UV and is less intense than at the equator. It's a warm color and weak at night. Horticulturalist brains is rare find but nature can be backward enginered by regular pot heads.

 

[BigSm0]

Is the amount of umols put out in relation to wattage and efficiency part of the soup?

Do autos need half DLI spread out over 150-200% the time a photo needs?

Would changes in spectrum allow stronger light? Can a plant manage being blasted by 3500k for 24 hours for 8 weeks or does it need a range of spectrum?

Efficiency is a huge part of figuring out the amount of light you are actually giving your plants. 100 watts of epistar leds and 100 watts of higher quality cobs is no comparison.
My thoughts early on was compare (Lights on) time while giving the plants the best quality light, coverage and intensity I could. The math will drive most people crazy and the best part of doing a grow test is you don’t end on a number you end with a grown plant. I have found the above to be the best wattage while using my cobs. One reason it’s lower than most is the cobs can be spaced as you want. Most lights sold are set up for these higher wattage per square foot even while being more efficient than Hps. The disadvantage is you can’t easily decrease the wattage. You would either need to sacrifice coverage which would happen by spacing them further apart than recommended or by dimming. Paying for a light that’s to powerful so you just use half of its power. By spacing the cobs as you want you can set the intensity and coverage to suit plants like autos better. For example you can take 500 watts and dim it to 50% or you can just run 250 watts from the start while spacing as you wanted. I started by growing at 25 watts per square foot (1/2 of 50 which is equal dli as photos at 12 hours) and the results were astonishing. I continued to go lower and lower till I saw a negative effect. What’s funny about all of this is some still won’t believe it and most didn’t when I first started talking about it 2+ years ago. I have nothing to gain by telling people less wattage. It’s actually the opposite and I regularly tell people to purchase less lights from me than they originally wanted. You just have the opportunity to gain. Better plants at a lower setup cost and operating cost

Do we know the optimum DLI for cannabis? How much does it vary by strain? Is it a constant total no matter the daily light regime, or does it vary? Lots and lots of questions. None easily tested specifically for autos due to genetic variation between seeds...

In the meantime, pragmatic experience suggests to me that trying less light may work reasonably well with autos. That will certainly be one focus of my next auto grow.

Happy light adjustment all.

Without getting to technical, most here are are at or around 50 watts per square foot. That’s miles away from where most AutoCob users are at. My thread in the Cobshop section goes over quit a few grows showing the results. Dabber here now at 9 watts per square foot with numerous other grows the same way and thousands of others in the (cobmob). Not only growing the same or better plants but doing it for a MUCH lower cost. I wish I had the time to devote to the exact specifics of every detail regarding dli and strains. I have just taken the 1+1 approach and it’s really that easy.

 

[4d-Rock]

That's the thing though. Everyone has an opinion. At the very least I'd like to pick the brain of a horticulturalist or plant sciences major to have a reasonable discussion.

On one hand we have people basically saying that Ruderalis can metabolize 24/7 whereas science says important processes occur during the dark period. Is Ruderalis really getting 24/0 in it's natural environment or does light spectrum+intensity play a role in the semblance of 24/0 lighting? Is the plant seeing 24/7 light that it can photosynthesize?

Another thing to consider is that most Auto strains are only 5-10% of the Ruderalis strain. So even in the case where Ruderalis can metabolize 24/7, it wouldn't make sense to assume that a plant which is for example 95% Indica/Sativa and 5% Ruderalis to take on entirely the lighting requirements of the 5% part of its genetics.
I'm no horticulturist, just trying to reason things out in my own brain.

Also, I'm currently running 95w of COBs in a 2x3 space...so just shy of 16 w/sq ft.

 

[BigSm0]

It’s been awhile since I have done one of these.
The difference between auto and photo needs.
In a 5x5 grow room 25sq feet

At 50 watts per square you’d need 1250 watts. 50x25
Multiply that by 12 which is the length of time photos flower .
12x1250 is 15,000 watts per day.
Now if they were autos run for 24 hours
24x1250 is 30,000 watts per day.
By giving an auto the same 50 watts per square foot you are giving your plant twice the light it’s entire life.

Another factor is the efficiency of the lights. Hps with its poor design suffers many losses on top of its lower efficiency. Factoring this in and being used on top of photo period plants I agree 50 watts per square foot is ideal. I actually ran the same exact setup before going to cobs. Comparing that to an auto grow while using a directional cob for twice the length of time isn’t accurate at all.

 

[Death The Cultivator]

Efficiency is a huge part of figuring out the amount of light you are actually giving your plants. 100 watts of epistar leds and 100 watts of higher quality cobs is no comparison.
My thoughts early on was compare (Lights on) time while giving the plants the best quality light, coverage and intensity I could. The math will drive most people crazy and the best part of doing a grow test is you don’t end on a number you end with a grown plant. I have found the above to be the best wattage while using my cobs. One reason it’s lower than most is the cobs can be spaced as you want. Most lights sold are set up for these higher wattage per square foot even while being more efficient than Hps. The disadvantage is you can’t easily decrease the wattage. You would either need to sacrifice coverage which would happen by spacing them further apart than recommended or by dimming. Paying for a light that’s to powerful so you just use half of its power. By spacing the cobs as you want you can set the intensity and coverage to suit plants like autos better. For example you can take 500 watts and dim it to 50% or you can just run 250 watts from the start while spacing as you wanted. I started by growing at 25 watts per square foot (1/2 of 50 which is equal dli as photos at 12 hours) and the results were astonishing. I continued to go lower and lower till I saw a negative effect. What’s funny about all of this is some still won’t believe it and most didn’t when I first started talking about it 2+ years ago. I have nothing to gain by telling people less wattage. It’s actually the opposite and I regularly tell people to purchase less lights from me than they originally wanted. You just have the opportunity to gain. Better plants at a lower setup cost and operating cost


Without getting to technical, most here are are at or around 50 watts per square foot. That’s miles away from where most AutoCob users are at. My thread in the Cobshop section goes over quit a few grows showing the results. Dabber here now at 9 watts per square foot with numerous other grows the same way and thousands of others in the (cobmob). Not only growing the same or better plants but doing it for a MUCH lower cost. I wish I had the time to devote to the exact specifics of every detail regarding dli and strains. I have just taken the 1+1 approach and it’s really that easy.

When I did the PAR testing for my diy bridgelux build, made purely on specs, I went with 500 watts despite initially wanting 600 but not wanting c02. I prefer the strip builds and before I learned about them I wanted to do a 1212 x 12-16 cob fixture but the cost was high. But I grow photos much more than autos so I never think about adding, moving or doing much more than testing my lights.

I agree that epistar is not Samsung and many growers get taken paying good money for a Roleandro with a different phosphorus coating. A lot of people just seem to be concerned with yield and get misled by manufacturers saying something can yield x.x grams per watt.

What's your opinion of linear lighting compared to dense packed cob styles? UV, Reds, tunable light spectrums?

 

[Death The Cultivator]

Another thing to consider is that most Auto strains are only 5-10% of the Ruderalis strain. So even in the case where Ruderalis can metabolize 24/7, it wouldn't make sense to assume that a plant which is for example 95% Indica/Sativa and 5% Ruderalis to take on entirely the lighting requirements of the 5% part of its genetics.
I'm no horticulturist, just trying to reason things out in my own brain.

Also, I'm currently running 95w of COBs in a 2x3 space...so just shy of 16 w/sq ft.

If we consider DLI then there has to be a point of saturation where a 18/6 is enough light.

 

[Blu_tri]

As we spoke the other day dabber the numbers don’t lie. 9.6 watts per square foot and the only grow I’m seeing come close is @Blu_tri at 22 watts per square foot. Nothing gets my blood pumping like someone telling me I need to do something differently when I continuously dominat that persons wildest expectation. Math and numbers are fun but real world results are the true test.

Like many here I listened to the consensus on wattage needed for ideal growth. After a few grows years ago with my newly purchased cob lights I found it wasn’t working. When I thought about the hours of light autos receive vs photos it all made sense. I multiplied the wattage by the hours of use. My autos were getting hammered. Say you are running 500 watts on photos at 12 hours per day and running the same 500 watts on autos at 24 hours per day the autos are getting twice the light per day. It’s clear as day. So the first thing I did was messaged the owner of the light company and asked him to consider a smaller light a little more suited towards Auto growers. My 468 watts packed into a 20” square grow light was way to powerful. He laughed at my idea so that’s when I made my own. Since I have proven this isn’t just a theory and the consensus was wrong. You WILL do better with 15-20 cob watts over 50 on autos and for photos you will do better with 20-30 cob watts rather than 50.

https://www.autoflower.org/threads/bigsm0-and-the-cob-addiction.61479/

I think my average was around 11-15 watts per square foot in most grows.

@BigSm0 thanks for the heads up. You told me 6 auto cobs in a 4x4 would burn a hole in the floor. The girls are saying that you are right. They are lighter in color in the direct light, while being a lovely color below. BigSmO You gave us all a new way of thinking when it comes to lighting. Your autocobs are the best. 1 cob -1 plant. If your results aren’t good, it’s growers error. It’s too late to remove the extra cobs . I don’t want to shock my girls. My current run is looking fantastic and are just getting over transitioning @ 28 - 35 days. F1 , F2, and f3’s all looking like twins. No topping on the f3’s. It’s easy to see how amazing the cobs are. I finally have a tent I can show off and be proud off. My girls aren’t beat to heck and back. And just like the cobs, autos require a new way of thinking. Those with the discipline to Learn new skills, will be rewarded... those who refuse to learn and keep dong the same ole thing, will get crappy results and never see the magic of the autocob.

 

[4d-Rock]

@BigSm0 thanks for the heads up. You told me 6 auto cobs in a 4x4 would burn a hole in the floor. The girls are saying that you are right. They are lighter in color in the direct light, while being a lovely color below. BigSmO You gave us all a new way of thinking when it comes to lighting. Your autocobs are the best. 1 cob -1 plant. If your results aren’t good, it’s growers error. It’s too late to remove the extra cobs . I don’t want to shock my girls. My current run is looking fantastic and are just getting over transitioning @ 28 - 35 days. F1 , F2, and f3’s all looking like twins. No topping on the f3’s. It’s easy to see how amazing the cobs are. I finally have a tent I can show off and be proud off. My girls aren’t beat to heck and back. And just like the cobs, autos require a new way of thinking. Those with the discipline to Learn new skills, will be rewarded... those who refuse to learn and keep dong the same ole thing, will get crappy results and never see the magic of the autocob.

That’s an amazing looking tent!

 

[LazyNhazy]

Blueberry cheesecake under 300w qb in a 2x4.