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

[pop22]

And one of the factors of DLI is that plants can only process a certain amount of phtotons per day, and that time is needed to handle all other processes involve in the production and transport of sugars, etc. I totally agree that there are too many factors to make a blanket statement

You nailed it in this post. There is no magic DLI number for plants, but there are suggestions starting to form. The engineer for Amare lights told me that with their testing, they found certain plants just have a much higher threshold for intensity. I've talked to commercial growers that have seen light bleaching on clones sitting next to non-bleached clones from the same plant, etc (I totally believe in epigenetics, stress and environment can cause gene expression.)

Going from 18/6 to 24/0 is a 25% increase in light hours (also consumption of power.) But the results aren't that apparent (certainly not a 25% increase in production or weight,) which is a huge marker in the defense of "more light hours isn't necessarily better." We know autoflowers thrive under a certain amount of light (and start to suffer with less,) but factor in light intensity and spectrum and now you've got two rolling variables (seldom talked about.) Are growers seeing better results on 24/0 using cheaper, budget lights? Are grower seeing better results at 18/6 using high PPFD lighting? Way too many variables to make a concrete statement.

There's one variable though that I know for 100% sure. If you grow all year round (autoflowers) assuming a 90 day average harvest, that's 6 hours every day you're adding on to your electric bill from lights, fans, etc. 24 hour lighting at 365 days is 8,760 hours. At 18 hours, it's 6,570 hours. That's 2,190 hours difference between the two, which is with NO EXAGGERATION an entire autoflower grow's worth of electricity. You could have pulled an ENTIRE extra grow out of that 6 hours of juice you're burning every day. I'd take a fresh harvest over a gamble of "maybe this is going to pull more weight" any day of the week personally.



The C3 statement is the most common (and in my opinion, overused and misunderstood statement) that people use in the 24/0 lighting defense. Food for thought, about 85% of all plant life on earth is a C3 plant. Very few parts of the planet have extended periods of 24 hour light or darkness. Just because plants have the ABILITY to do so, doesn't mean it's the MOST OPTIMAL thing to do. You can drive a car at 200+ mph if it's capable of doing it, but is that the most efficient thing on your gas tank? Or driving through a school zone? Or pretty much driving anywhere? lol

Plants also don't need the same amount of light during different phases of growth. You don't feed an infant a T-bone steak, right? Just like seedlings not needing much for nutrients starting out, they don't need this overpowering amount of light either.

 

[Son of Hobbes]

And one of the factors of DLI is that plants can only process a certain amount of phtotons per day, and that time is needed to handle all other processes involve in the production and transport of sugars, etc. I totally agree that there are too many factors to make a blanket statement

Exactly. That's why I think a grow with a less efficient light may see more growth, while someone with a higher efficiency light is seeing the same growth with less light hours. Could be the same amount of photons delivered, just one takes more hours to do so. Then you get into the light limitations of ambient CO2, etc etc etc.

 

[Disburped]

And one of the factors of DLI is that plants can only process a certain amount of phtotons per day, and that time is needed to handle all other processes involve in the production and transport of sugars, etc. I totally agree that there are too many factors to make a blanket statement

I have no idea cause I do mix up bro-science with real science sometimes but this daily light intake is a very un-natural process cause in nature the light is never the same, sunshine, white clouds, dark clouds and such. Then you have temperature changing, night temperature can be cold and plant processes can be slow in the day and night. Then you have humidity, it raises in the night and in the morning plants stand in fog. How to translate all of this to a daily intake for weed?
It's just a bit weird that plants don't try to use the light if they can and when they can and that it would have a clock that stops all the good stuff from happening.

 

[Son of Hobbes]

I have no idea cause I do mix up bro-science with real science sometimes but this daily light intake is a very un-natural process cause in nature the light is never the same, sunshine, white clouds, dark clouds and such. Then you have temperature changing, night temperature can be cold and plant processes can be slow in the day and night. Then you have humidity, it raises in the night and in the morning plants stand in fog. How to translate all of this to a daily intake for weed?
It's just a bit weird that plants don't try to use the light if they can and when they can and that it would have a clock that stops all the good stuff from happening.

It's not unnatural at all actually, the science behind it is simply trying to explain and quantify the variables of how/why it happens in nature. If you give too much light to a plant, or if the light is too close (increasing the PPFD (which is intensity,)) photo oxidation can begin to occur (light bleaching.) Plants become "light limited" at certain ambient CO2 levels in the atmosphere as well. So you could have this just CRAZY friggin grow light pounding down photons on your plant, but if other variables aren't in place, the plant cannot physically use that additional intensity. Why waste energy?

One thing to note in the comparison here, nature is often NOT optimal in the sense of maximizing results (there's something to be said about being able to control every variable in a grow.) Tough to control an early frost, or heavy rains that bring mold, or having neighbors that grow out male plants that pollinate your shit (grumble grumble grumble.)

Think of photons like a bunch of ping pong balls you're throwing at the plant. The plant can take so many of those direct hits, but after 24 hours of X amount of hits, it's saying "bro, let's do this tomorrow, I need a rest." Sure, you could keep going. But you could also give it a rest. What is best? It's not clear or obvious that throwing 6 more hours of ping pong balls is doing anything (anecdotal at best.)

If there's a way to find common ground on "how much light is enough" vs "how much light is NOT enough," we can help growers everywhere make better, more informed decisions (and possibly save money.) And the science is there as dots, we just have to connect them to make it the picture.

 

[Disburped]

Btw we know plants can use lights 24/7 cause if we flash a photoperiod it will stop the process, that is a photosynthetic reaction. If we can measure it in harvest yield is a different question cause what's best for us may not be best for the plant. So if you push the light intensity above sunshine level on earth you will come to a limit, duh, for weed that limit is high. When that limit is passed it becomes strange to talk about optimal growth cause the limits are pushed so far we have to adjust all other variables to make the plant survive. I can do it but I can't call it natural or optimal growth cause I need a plant adjusted to life on mars, weed is a tough plant and in nature optimal growth is the plant that makes it and make offspring that survive and do the same.
All I want to know is, how to the plant react if I do this or that, why and how!

 

[Son of Hobbes]

Btw we know plants can use lights 24/7 cause if we flash a photoperiod it will stop the process, that is a photosynthetic reaction. If we can measure it in harvest yield is a different question cause what's best for us may not be best for the plant. So if you push the light intensity above sunshine level on earth you will come to a limit, duh, for weed that limit is high. When that limit is passed it becomes strange to talk about optimal growth cause the limits are pushed so far we have to adjust all other variables to make the plant survive. I can do it but I can't call it natural or optimal growth cause I need a plant adjusted to life on mars, weed is a tough plant and in nature optimal growth is the plant that makes it and make offspring that survive and do the same.
All I want to know is, how to the plant react if I do this or that, why and how!

Understanding the "why" of those limitations is part of what we're discussing And the thresholds aren't as high as you'd think IMO.

The ambient CO2 available in the atmosphere in most places is around ~400 ppm, which limits the effectiveness of photosynthesis (meaning that photosynthesis becomes "light limited" based on the CO2 level.) Temperature, humidity, CO2, strength and type of nutrients used, humidity, etc, all have limiting factors (and they all factor in with each other.) There is nothing wrong at all with growing at normal ranges for these variables, but you can't ignore the science behind the limitations (knowing that if we increase variables X, Y, and Z in the right proportions, that it's possible increase the overall effectiveness.)

I could just switch to light beer to drop a few pounds, or I could change several variables in my life style and REALLY get in shape. See what I mean?

 

[Son of Hobbes]

I'm not switching to light beer, that was just an example. Don't want to worry anyone.

 

[pop22]

Guinness Photon?

I'm not switching to light beer, that was just an example. Don't want to worry anyone.

:smoking:

 

[Disburped]

Understanding the "why" of those limitations is part of what we're discussing And the thresholds aren't as high as you'd think IMO.

The ambient CO2 available in the atmosphere in most places is around ~400 ppm, which limits the effectiveness of photosynthesis (meaning that photosynthesis becomes "light limited" based on the CO2 level.) Temperature, humidity, CO2, strength and type of nutrients used, humidity, etc, all have limiting factors (and they all factor in with each other.) There is nothing wrong at all with growing at normal ranges for these variables, but you can't ignore the science behind the limitations (knowing that if we increase variables X, Y, and Z in the right proportions, that it's possible increase the overall effectiveness.)

I could just switch to light beer to drop a few pounds, or I could change several variables in my life style and REALLY get in shape. See what I mean?

Yes I understand, don't doubt it. What we discuss is how many watts we waste on electricity cause we are not allowed to grow a field cause if we did grow a field, yield per plant would be less important than yield per field. See where I am going?
We all grow the plant in sub-optimal environment cause we can't grow a field on mars yet and the sun is the best light cause it's no fuzz and free. Production cost and labour intensity per weight of resin is the boring measurement. Indoor we can't compete with sun and field so what we really discuss is how to grow an optimal grow in a sub-optimal environment by cranking up all the parameters to life on mars. Let's do it, I am all in but make no mistake, we are just cranking it like potheads and yet we don't know enough. Will the medicine be better if it's dry and hot or dry and cold, maybe moist and cold or moist, cold and low light intensity?
We don't know yet cause the knowledge is lost and we must find it again, let's do that by messing with all the variables and smoke the dope!

 

[WilliamNewbridge]

27 Watts/Square Foot....

Should be hovering right around a gram/watt in my little tent.