COB GROW how many lumens I go for flower

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pollen205

Well-Known Member
Hi today I buy lux meter and want to test my 200w diy cob light so I meausure the light on top of the plant and give me 25 k Lux on top of the plant and 16K-20K- on lower buds...

Is this good or do I need to dim my cobs to more w so more lumens ???But I really dont want to have a light bleech...I am at midle of flowering cycle...

I have biotabs food and hoping that is ok for strong light like this
The plant start trichomes production very good under this light but for last 2 days in my eye she is the same like nothing is happening...
And really start drinking water...I have a fealing that if I water every day that would be ok , but I always do 1 day without water
 
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pollen205

Well-Known Member
cob diy 200 w set 4x 50 w each but i can dim it to 70w each...
citizen CLU048 1212 gen 6 3500k 80cri

30 cm from plant

plant is medium size
 
Moflow

Moflow

Well-Known Member
You need to get the light up to around 40k lux for flowering, imo.
12" is a nice distance for the cobs.
I'd imagine the plant is nearly at the end of stretch by now.
I'd turn the wattage up slowly to full blast and keep an eye on the plant.
What driver are you using, is it the MW 185 1400ma?
Maybe throw up a pic or two of the plant.....
I'm not sure of the biotabs product.
Get a bottle of tomato food for the plant if things are tight :lol:
 
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pollen205

Well-Known Member
@Moflow you legend....

Yes you are correct I can see that stracth is almost done... :)
Yes you are correct about my mean well driver ;)

Ok on the Internet and in store where I buy cobs they say that are the best at 50 w so 200 w reading in wall meter...
Ok I will do so ...so tommorow I go from 200w to 208 w...

now my lux meter say 26 000 so i really must hit 40 000
and I notice that gap between my cobs give my small readings so I must put cobs closer each other...

Biotabs for me is good because I have nothing with ph...
Sound easy and see some good resault on forums...

So what nutrients line can you recommend for new grower who dont want to have any ph problem...
with bio tabs pure water and plants looking really good

tommorow picture
 
Kkesu

Kkesu

Active Member
Lumens are for humans, they're based on how the human eye sees light, plants don't see light like that, look up a video on PAR(Photosyntetically Available Radiation) as it's how much usable light the plant is actually getting to grow with, it's far more accurate for what's actually important to them.
 
Moflow

Moflow

Well-Known Member
I spot measured PAR with an APOGEE par meter for 4 x cxb3590 on an 18" x 12" frame connected to a MW 185h 1400mA driver in a 32" x 32" tent with 4 plants.
183 wall watts.
10" - 12" from canopy.
Average reading of around 800 umols.
PAR meters are quite expensive for a hobby grower and unnecessary lol but it was a group buy.
Also, some lux meters are better than others.
@Randomblame has a half decent lux meter he uses, I can't remember the model, perhaps he'll chip in.......:lol:
 
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pollen205

Well-Known Member
haha I know for par metar but i am hobby and new ....and that shit is ton of money...
this is not china lux meter so I hope that is good
 
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pollen205

Well-Known Member
Moflow said:
I spot measured PAR with an APOGEE par meter for 4 x cxb3590 on an 18" x 12" frame connected to a MW 185h 1400mA driver in a 32" x 32" tent with 4 plants.
Click to expand...
my frame for grow tent 80x 80 is 60x60 or 24x24 inches...
and the cobs are on the every corner so distance between them is 40 cm....
I must concetrate light closely​
 
Randomblame

Randomblame

Well-Known Member
pollen205 said:
my frame for grow tent 80x 80 is 60x60 or 24x24 inches...
and the cobs are on the every corner so distance between them is 40 cm....
I must concetrate light closely​
Click to expand...

Nope! That will only end in an hotspot in the center. With your frame you have one COB in the center of each 40x 40cm area. Almost perfect, I'd change nothing!
Different lux-meter readings can differ a lot when not calbrated. Also some lux-meters have a switch to change the measuring range.. or you need to multiply the results. I would not worry about the readings, a 200w fixture should be in the range @Moflow mentioned above when hanging 12" above the canopy.
My lux-meter shows 40.000lx and converted into μMol/s/m2 that should be 580μmol/s. But measured with a friends PAR meter the reading were much higher and I got +700μMol/s. That's almost 20% difference and my lux-meter should actually show 50klx, not only 40.

It's much more important now that the light is properly spread across the canopy and that there is as less wall loss as possible. Means the hanging height of the fixture should be high enough to not causing damage on the plants but in the same time as low as possible to reduce wall loss.
 
BuddyColas

BuddyColas

Well-Known Member
Randomblame said:
Nope! That will only end in an hotspot in the center. With your frame you have one COB in the center of each 40x 40cm area. Almost perfect, I'd change nothing!
Different lux-meter readings can differ a lot when not calbrated. Also some lux-meters have a switch to change the measuring range.. or you need to multiply the results. I would not worry about the readings, a 200w fixture should be in the range @Moflow mentioned above when hanging 12" above the canopy.
My lux-meter shows 40.000lx and converted into μMol/s/m2 that should be 580μmol/s. But measured with a friends PAR meter the reading were much higher and I got +700μMol/s. That's almost 20% difference and my lux-meter should actually show 50klx, not only 40.

It's much more important now that the light is properly spread across the canopy and that there is as less wall loss as possible. Means the hanging height of the fixture should be high enough to not causing damage on the plants but in the same time as low as possible to reduce wall loss.
Click to expand...
Interesting aside...I bought an Apogee PAR meter and the readings are about 20% hotter than my lux meter readings. I was wondering how I was getting such good results at around 600 umols. Turns out it was a really around 720ish umols really. So as you said, 40K lux is very productive and is really over 30 DLI on a 12/12 cycle.
 
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pollen205

Well-Known Member
Randomblame said:
Nope! That will only end in an hotspot in the center. With your frame you have one COB in the center of each 40x 40cm area. Almost perfect, I'd change nothing!
Click to expand...
Ok that is true but I have just one plant , and she is on center of the tent where I have readings 25 000lux
and on the same height under cobs I have 30 000


I dont have cheap china lux meter , I have velleman lux meter DEM300 and it is a brand new so I want to bealive that the readings are correct
I water correct ,let the medium dry good and water to drainage then stop,collect water from tent and then wait again 2-3 days then water...
I dont give it any food...I give her 4 biotabs pills in soil then add on 3 week ago...
And her recive bactrex and orgratrex when she start flowering full dose...once....that is it...
that how Biotabs said,and I dont know if I can add it more

what do yoo think from the pic , is she hungry...
the steems are not purple that much but the some spots of purple are there

So please look at the picture and tell me if I need to closer my cobs and please please if you can tell me how many more days
 
Chip Green

Chip Green

Well-Known Member
BuddyColas said:
I was wondering how I was getting such good results
Click to expand...
I have pondered, suspected(secretly hoped) my Dr. Meter brand LUX device was giving "cold" readings....
My gen1 BXEB builds have been satisfyingly exceeding expectation at 40K Dr. Meter LUX for many runs...I did one saturation build with 15x 560mm 3000K Gen1 BXEB @700ma, on a 28" frame, had 65k+ at 12" from canopy, and saw little to none gain in volume...Perhaps even an overall LOSS of yield potential due to the smaller footprint, in comparison to the usual 40K Dr. Meter LUX sized framework...
Under my collective conditions, I need not exceed 40K Dr. Meter LUX.

These are great times Men, great times we live in.
 
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1212ham

Well-Known Member
Randomblame said:
My lux-meter shows 40.000lx and converted into μMol/s/m2 that should be 580μmol/s. But measured with a friends PAR meter the reading were much higher and I got +700μMol/s. That's almost 20% difference and my lux-meter should actually show 50klx, not only 40.
Click to expand...
I suspect my lux meter also reads low. Are there any easy to see signs of to much light?
 
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