12 Plants Under ~600w Cob Leds

MeGaKiLlErMaN

MeGaKiLlErMaN

Well-Known Member
I would drop the light to around 2ft, thats where I have mine for veg, then again I dont have a dimmer so its going to use the power no matter what so might as well hit the plants a bit harder.
 
butterbudface

butterbudface

Well-Known Member
MeGaKiLlErMaN said:
I would drop the light to around 2ft, thats where I have mine for veg, then again I dont have a dimmer so its going to use the power no matter what so might as well hit the plants a bit harder.
Click to expand...
im running mine at 1.55A, dropping my light to 2ft will burn them to shit?
 
MeGaKiLlErMaN

MeGaKiLlErMaN

Well-Known Member
butterbudface said:
im running mine at 1.55A, dropping my light to 2ft will burn them to shit?
Click to expand...
Idk you would have to check the PPF/D thats coming out, but yeah you might be right. You can easily get 1500PPFD then. I run mine at 50W each (1.4A) and I get 830PPFD so I would think you are good to lower them, mine are at 2ft.
 
butterbudface

butterbudface

Well-Known Member
MeGaKiLlErMaN said:
Idk you would have to check the PPF/D thats coming out, but yeah you might be right. You can easily get 1500PPFD then. I run mine at 50W each (1.4A) and I get 830PPFD so I would think you are good to lower them, mine are at 2ft.
Click to expand...
then they should be fine i think, but i wont drop the lights that low, they stress faster IMO, I'm just going to let them fill the screen as is, then ill lower them when i flower?
 
MeGaKiLlErMaN

MeGaKiLlErMaN

Well-Known Member
butterbudface said:
then they should be fine i think, but i wont drop the lights that low, they stress faster IMO, I'm just going to let them fill the screen as is, then ill lower them when i flower?
Click to expand...
I would drop slowly and look for burns or bleaching after each day, once you see it then move up 6 inches or so and then you know thats where the light is too intense... Or buy a par meter.
Think of lowering it a bit as putting the afterburners on lol.
 
butterbudface

butterbudface

Well-Known Member
MeGaKiLlErMaN said:
I would drop slowly and look for burns or bleaching after each day, once you see it then move up 6 inches or so and then you know thats where the light is too intense... Or buy a par meter.
Think of lowering it a bit as putting the afterburners on lol.
Click to expand...
I only go to the grow once every 10 days, next time i'm going there i'm flipping them for flower.
 
butterbudface

butterbudface

Well-Known Member
HydroRed said:
I'd agree it seems a bit far away from the plants? I run 8 cxb3070's run at 50W @1400mA and I have mine about 14-16" from the top of the plants with plenty of room to spare before any light burn happens. It'll keep the early flower stretch from getting too bad. I've run them as close as 10" on my last grow.
Click to expand...
Ok ill drop the light to around 700mm
 
PhotonFUD

PhotonFUD

Well-Known Member
This is one way to help guide you for height.

You want an even distribution of light across the entire canopy - uniformity. Basically spread your light outs so that the overlaps will match the centers. From there you be looking for the 'sweet spot' where your lights will hit optimal photosynthesis (~400 umoles) and that will be the 'bottom' height for you. From there on up will be the optimal 'zone' for growth. With LED you can put them close but you can burn the plants so keep that in mind. Figure that out first as the minimum height to canopy.

Here is an example. I have a panel that puts out 730 at 8" (20cms), 510 at 12" (30cms) and 260 at 18" (50cms). My target of ~400 umoles is somewhere between 12" and 18" so I can expect to have an optimal zone at ~12" from the lamp. Plants grow taller so I want to make sure that I maximize the amount of exposed leaf area to optimal light. By hanging the lamp at 12", the current top of the canopy is getting a uniform ~510 umoles and as it grows taller will be able to handle the 730 at 8" giving it at least 4" of grow room. The lower regions of the canopy will progressively increase from ~260 umoles up to the optimal zone which begins at roughly 14" from the lamp for that same 4" of grow room.

If you expect 4" of vertical growth in a week, this example would only require adjustment on a weekly basis.
 
butterbudface

butterbudface

Well-Known Member
PhotonFUD said:
This is one way to help guide you for height.

You want an even distribution of light across the entire canopy - uniformity. Basically spread your light outs so that the overlaps will match the centers. From there you be looking for the 'sweet spot' where your lights will hit optimal photosynthesis (~400 umoles) and that will be the 'bottom' height for you. From there on up will be the optimal 'zone' for growth. With LED you can put them close but you can burn the plants so keep that in mind. Figure that out first as the minimum height to canopy.

Here is an example. I have a panel that puts out 730 at 8" (20cms), 510 at 12" (30cms) and 260 at 18" (50cms). My target of ~400 umoles is somewhere between 12" and 18" so I can expect to have an optimal zone at ~12" from the lamp. Plants grow taller so I want to make sure that I maximize the amount of exposed leaf area to optimal light. By hanging the lamp at 12", the current top of the canopy is getting a uniform ~510 umoles and as it grows taller will be able to handle the 730 at 8" giving it at least 4" of grow room. The lower regions of the canopy will progressively increase from ~260 umoles up to the optimal zone which begins at roughly 14" from the lamp for that same 4" of grow room.

If you expect 4" of vertical growth in a week, this example would only require adjustment on a weekly basis.
Click to expand...
i have 4 vero 29s on a 450mm spacing driven at 1.55a, what would the optimal distance be then? also since i lowered the lights the plants seem to have burnt leave edges? Or is that just from incorrect feeding?
 
You must log in or register to reply here.
Top