Cree 3590 3500k 1.3mA how far from brand new sprouted seedlings?

Uberknot

Uberknot

Well-Known Member
Hey There!
I have a light I built and I am just starting with COB lights and am trying to get a ballpark distance for fresh seedlings. I have the light placed about 30 inches above atm and have searched and read a whole bunch of threads from all over the web and the responses vary.

The 3590 COBS are spaced about 7 inches apart.IMG_0466.JPG It's running at 1.3 mA

So has anyone used just cobs to grow from new seedlings and what would be a safe distance from them?
IMG_0625.JPG

Thanks in advance, Uber.
 
nogod_

nogod_

Well-Known Member
Can you dim it?

Uberknot said:
Hey There!
I have a light I built and I am just starting with COB lights and am trying to get a ballpark distance for fresh seedlings. I have the light placed about 30 inches above atm and have searched and read a whole bunch of threads from all over the web and the responses vary.

The 3590 COBS are spaced about 7 inches apart.View attachment 3755006 It's running at 1.3 mA

So has anyone used just cobs to grow from new seedlings and what would be a safe distance from them?
View attachment 3755011

Thanks in advance, Uber.
Click to expand...
 
nogod_

nogod_

Well-Known Member
Sure if youre lazy that will work.

I have seedlings growing under a 200w 3000k bar right now dimmed to 80w. The light is <12" away and everybody looks stoked.
 
Uberknot

Uberknot

Well-Known Member
nogod_ said:
Sure if youre lazy that will work.

I have seedlings growing under a 200w 3000k bar right now dimmed to 80w. The light is <12" away and everybody looks stoked.
Click to expand...
HEH....well the idea was maybe it would just keep growing into the light and I could just let it be rather than messing with the dimming and having to lower and the raise it back up. I figure the more light the more penetration as the plant keeps growing to it. The lowest wattage I could go is around 105W so I could probably get away with what 16 inches above?

and thanks for the response it gives my something to think about for sure.
 
nogod_

nogod_

Well-Known Member
Whatever works for you. I try not to use more than I need of anything but thats a topic for another thread.

If it was me I'd dim it down all the way, drop the light to 24" and see how the plants respond.

Uberknot said:
HEH....well the idea was maybe it would just keep growing into the light and I could just let it be rather than messing with the dimming and having to lower and the raise it back up. I figure the more light the more penetration as the plant keeps growing to it. The lowest wattage I could go is around 105W so I could probably get away with what 16 inches above?

and thanks for the response it gives my something to think about for sure.
Click to expand...
 
Desmond J

Desmond J

Active Member
I'd say that as long as you dont kill them (light burn or light deff), you can do whatever you want. Tho it's just a waste to use 200w on seedlings in that space, they don't even have real leafs yet.
But my point is, use the light so your plants behave the way you prefer: closer will keep them short and bussy, and farther will to the opposite.

I just went from full dim down (~100W) at 12", to full power (~210W) at 18", in the first 3 weeks... It stayed that way till just now (week 6), that I want them to stretch a bit and have them at 24".
 
Uberknot

Uberknot

Well-Known Member
I think I will test this out at the current height just to see.
Desmond J said:
I'd say that as long as you dont kill them (light burn or light deff), you can do whatever you want. Tho it's just a waste to use 200w on seedlings in that space, they don't even have real leafs yet.
But my point is, use the light so your plants behave the way you prefer: closer will keep them short and bussy, and farther will to the opposite.

I just went from full dim down (~100W) at 12", to full power (~210W) at 18", in the first 3 weeks... It stayed that way till just now (week 6), that I want them to stretch a bit and have them at 24".
Click to expand...

I am at (1.3mA)156 watts atm and 32" ( measured ) here is day 2. seems to be growing ok I will watch it and make any adjustments. I might be to far away who knows....IMG_0626.JPG
 
edgein123

edgein123

Well-Known Member
I run a similar setup only @ 3500K, 4 CXB3590 in a 2*2*6 tent.

They're dimmed to 700ma and are on 24/0.

I started around 2ft from seedling, and it almost seemed like 3ft would still produce enough light.

They're around 2 weeks old from seed and currently 20"from light.

Go my route and you'll come out with shorter bushier plants.

Just check how they respond, one of seedlings felt she could go as close as 12" (from sprout!!!) But the others seemed a bit overwhelmed so i raised all lights.
 
Uberknot

Uberknot

Well-Known Member
12 hours later....Still plugging along. Humidity 45-65% temps 72-82F, 20/4 lights.
IMG_0627.JPG
 
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Uberknot

Uberknot

Well-Known Member
ok, here we are 24 hours later and one more seedling. Growth so far is looking ok.

I Planted one more yesterday and that should come up in 2-3 days.

IMG_0632.JPG IMG_0633.JPG
 
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The Dawg

The Dawg

Well-Known Member
Brother I Started My Seedlings At 43 1/2 Inches. Using 175 watts @1.4mA And I have Left It Their :weed:
IMG_4230.JPG IMG_4231.JPG IMG_4235.JPG IMG_4236.JPG
 
MadNyeTheHydroGuy

MadNyeTheHydroGuy

Active Member
Regarding leds and seedlings, what would the symptoms look like for having your cobs to close? Would it be heat stress or bleaching? Any pics?
 
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