Do more lights equal more yield?

[Dr.B]

How many watts per sqft?

At 40% in a 3x3 light footprint, 9 square feet... its around 44 watts per square foot max. Going by the light output not what it draws from the wall.

 

[Dr.B]

At 40% in a 3x3 light footprint, 9 square feet... its around 44 watts per square foot max. Going by the light output not what it draws from the wall.

I think I max out, based on that math, at 122 watts per square foot in bloom. I'm the least qualified on this topic though. Really just looking deeper into it now after a couple years of learning the ropes and going into debt lol.

 

[Aqua Man]

I think I max out, based on that math, at 122 watts per square foot in bloom. I'm the least qualified on this topic though. Really just looking deeper into it now after a couple years of learning the ropes and going into debt lol.

What's the light draw from the wall?

Just woke up but going back to bed so check back in the AM

 

[Dr.B]

What's the light draw from the wall?

Just woke up but going back to bed so check back in the AM

685watt draw to 1000watt equivalent output from everything I can see. Plus another 100watts in t5 supplementing the big light... It will run on a standard outlet/breaker. I have a 20amp line/breaker feeding it, all the fans and half the room, never popped a breaker, electrical lines still cool with the ir thermometer... I'm not an electrician, that's how I gauge it.

 

[Dirtbag]

Im gonna do a post this week on DLI and light saturation to help ppl understand how this light stuff all actually affects the plants if I can find the time. There is a lot to consider and I have seen so many posts of ppl in veg burning the shit out of thier plants lately. Intensity changes the needed photoperiod and vice versa. In veg specifically you can grow under significantly less light than is needed for flower. This is because the photo period.

I somewhat respectfully disagree. I get my clones accustomed to the1000w HID's, ASAP, usually in less than a week after coming out of preveg, and I veg under them for a month. They Veg insanely fast under the 1000. I've kept plants under a 4 lamp T5 array, the same age as ones vegging under 1000's and after a month the T5 plants look about 1/6th the size of my 1k plants.

Just like the sun outdoors, it's at its peak in June and July when plants are in full on Veg mode, Light intensity from the sun actually tapers off in flower substantially.

I think what really matter is introducing them to low light first, and slowly ramping it up to full power over the course of a week, once the roots are developed. Just like moving plants outside.

Just a theory based on my techniques, and observation of plants grown under varying light intensity.

 

[Aqua Man]

I somewhat respectfully disagree. I get my clones accustomed to the1000w HID's, ASAP, usually in less than a week after coming out of preveg, and I veg under them for a month. They Veg insanely fast under the 1000. I've kept plants under a 4 lamp T5 array, the same age as ones vegging under 1000's and after a month the T5 plants look about 1/6th the size of my 1k plants.

Just like the sun outdoors, it's at its peak in June and July when plants are in full on Veg mode, Light intensity from the sun actually tapers off in flower substantially.

I think what really matter is introducing them to low light first, and slowly ramping it up to full power over the course of a week, once the roots are developed. Just like moving plants outside.

Just a theory based on my techniques, and observation of plants grown under varying light intensity.

I'm not sure what you disagree with?

1000w lights is not a good measurement. If it's 10ft or 1 ft over the plants is the important thing. It's intensity of light over photoperiod no matter the lighting used IMO. I mean the sun on the contrary to what ppl think is not at 100,000 lux for 16 hrs a day. It's the DLI that is important.

The hardening off plants is unusually UV related from the information I have seen.

I agree with what your saying. But it's very hard to compare indoor and outdoor because the sun intensity is not constant just like environment. Why we have good and bad crop years. What I'm getting at is the DLI. You can run a high light for less time with the almost identical results. Or a lower light for longer. I do feel a dark period is beneficial though

 

[Dirtbag]

I'm not sure what you disagree with?

1000w lights is not a good measurement. If it's 10ft or 1 ft over the plants is the important thing. It's intensity of light over photoperiod no matter the lighting used IMO. I mean the sun on the contrary to what ppl think is not at 100,000 lux for 16 hrs a day. It's the DLI that is important.

The hardening off plants is unusually UV related from the information I have seen.

Just the notion that they need less light in veg, but maybe I misinterpreted something.

Of course they can grow with less light in Veg, and yes they do need a lot of light to flower properly. I was just saying that more light is still better than less light, even in veg, as long as you arent stressing them with too much.

I dont have any fancy light meters but I usually try to keep it around 40-50000 lux with the lamps about 20" from the canopy in Veg. If anything I raise my lights to 24" in flower when I swap to HPS.

 

[Dr.B]

I've seen it/done it both ways, both with their own issues and both ways I had and have seen good results. My only issue now that I do save a bit of energy in a lower light veg, (by necessity, not much tent space) is the transfer into more intense light.

It takes a week or two of careful monitoring but I'm working it out.

 

[Aqua Man]

Just the notion that they need less light in veg, but maybe I misinterpreted something.

Of course they can grow with less light in Veg, and yes they do need a lot of light to flower properly. I was just saying that more light is still better than less light, even in veg, as long as you arent stressing them with too much.

I dont have any fancy light meters but I usually try to keep it around 40-50000 lux with the lamps about 20" from the canopy in Veg. If anything I raise my lights to 24" in flower when I swap to HPS.

Yeah I prob worded it wrong. You benefit from more light in flower because you only have 12 hrs to provide it. I find the same 40-50k in late veg but I find I have to increase slowly from seedling. In hydro I can do it quickly in dirt it looks like about 3 week before I could run 40kish

 

[Dr.B]

I've seen it/done it both ways, both with their own issues and both ways I had and have seen good results. My only issue now that I do save a bit of energy in a lower light veg, (by necessity, not much tent space) is the transfer into more intense light.

It takes a week or two of careful monitoring but I'm working it out.

Not that they "need" much less light in veg, that's not the point. The point is you don't need to give them big light in veg indoors to get the job done.

 

[Aqua Man]

Not that they "need" much less light in veg, that's not the point. The point is you don't need to give them big light in veg indoors to get the job done.

Yes that's why I'm trying to say. And because the lighting period is shorter in flower they can handle a more intense light for that duration without stress. The demand on CO2 also goes up with light intensity.

 

[Dan789]

My 600 watt twelve 3500K cob fills the 4x4 with 37.5 watts/per square foot. In veg when the plants are smaller I just unplug the two outer rows till the plants grow and need to be spaced out... I’m only driving them at 50 watts each as it’s the sweet spot with light production over heat...

 

[Aqua Man]

It's the concept that is important for new growers to understand. In doors we have control over this. You dont need all the fancy equipment simply find the light stress point of the plant over the day and back it off a but then you know your close to peak lighting. This will be different for 24/0 or 18/6 or what ever your lighting schedule is then when you flip to flower and reduce the photo period simple math can give you the % increase in lighting need to maintain the DLI and keep you close to the peak DLI if that makes sense

Here is a video on the concept.

 

[Tech4523]

An 18-hour photoperiod in veg with 500 micromoles per metered square per second calculates to a DLI of 32, for example. In flower, a 12-hour photoperiod at the same light intensity level is a DLI of 21.

This is why during flower they call for 600-1000 micromoles per meter.

DLI needs to be around 22 for photosynthesis and weed likes upto 65 DLI but to place that much micromoles you would need to supplement Co2. Optimal DLI with out Co2 is 35-50 range...this is why 400-600 micromoles for veg and 600-1000 for flower anything over 1000+++ requires Co2 supplement

 

[Aqua Man]

An 18-hour photoperiod in veg with 500 micromoles per metered square per second calculates to a DLI of 32, for example. In flower, a 12-hour photoperiod at the same light intensity level is a DLI of 21.

This is why during flower they call for 600-1000 micromoles per meter.

DLI needs to be around 22 for photosynthesis and weed likes upto 65 DLI but to place that much micromoles you would need to supplement Co2. Optimal DLI with out Co2 is 35-50 range...this is why 400-600 micromoles for veg and 600-1000 for flower anything over 1000+++ requires Co2 supplement

This... +1 and why you see someone with the same light intensity but doing 24hr lighting having light stress and others at same intensity 18/6 being close to perfect.

I think ppl confuse the intensity needed for cannabis as a whole. Using the same intensity at different photo periods to be the same and it's absolutely not.