Lighting COB for single plant growth help

[CasualRascal]

Hello
Complete newbie here, read a lot and am now planning to grow my first auto soon
I am in the process of writing a shopping list and planning what to do exactly

I will get a grow tent and grow only one auto mazar at a time, therefore I'll get a somewhat small grow tent.
Planning to go with COB led for lighting
From what I read, 1x 50W white COB will not be enough for decent yields
Thinking of getting 1x 100W white COB

Questions:
How far from the plant should the 100W white COB be positioned?
Can these kind of lights stay switched on 24 hours [w/cooling fan on heatsink]?
Would you go 2x50W or 1x100W if you were to only ever grow one plant only at a time?

I have read contradicting opinions regarding LED lights: some claim they should be positioned further away from the plants otherwise they'll burn the leaves, some say they can be positioned real close with no issues. I imagine these people are talking about different kind of leds, what about the white COB I am planning to get?

Lemme know!

 

[Proph]

One 50w cob should be able to grow one plant with out a problem. 2 50w cobs will do even better. If your goal is high yeild, then use as much light as possible. With cobs its not reallt about "watts per cob".. Its more about how efficient they are running. A 100w cob (Depending on model and manufacture recommendations) is less efficeint than a 50w cob. Which means less usable light. With cobs, the lower the watts, the more effeinct the cob is. Most have great efficiency at around 50w. I would definately do two 50w over one cob running at 100w. @bob142g has an amazing example of this in his journal..

https://www.autoflower.org/threads/blue-mystic-under-bigsmos-cob-lights.58800/page-5#post-1455321

He started with one 55w [HASHTAG]#Autocob[/HASHTAG] and later added a second 55w [HASHTAG]#Autocob[/HASHTAG] for a one plant grow... And he grew a flippin TREE! Lol. So have a look around at a few journals in the Cobshop.net thread or in the DIY lighting thread and you will find plent of examples. I personally run two 55w [HASHTAG]#Autocobs[/HASHTAG] for three plants in a 3x3. Just got a third [HASHTAG]#Autocob[/HASHTAG] this week so I can run one more plant. So 3 cobs.. 4 plants (two 3gal, two 5 gal) in a 3x3 and it definitely enough. Lights are ran 24/7 and height depends on stage.. For a small grow tent, like a 2x2 or 3x3.. Just hang it at the top and let the plants grow to the light. Mine are kept at the top of my tent.. Hope this helps a tad and welcome to AFN!

 

[Green Goblin]

Hello
Complete newbie here, read a lot and am now planning to grow my first auto soon
I am in the process of writing a shopping list and planning what to do exactly

I will get a grow tent and grow only one auto mazar at a time, therefore I'll get a somewhat small grow tent.
Planning to go with COB led for lighting
From what I read, 1x 50W white COB will not be enough for decent yields
Thinking of getting 1x 100W white COB

Questions:
How far from the plant should the 100W white COB be positioned?
Can these kind of lights stay switched on 24 hours [w/cooling fan on heatsink]?
Would you go 2x50W or 1x100W if you were to only ever grow one plant only at a time?

I have read contradicting opinions regarding LED lights: some claim they should be positioned further away from the plants otherwise they'll burn the leaves, some say they can be positioned real close with no issues. I imagine these people are talking about different kind of leds, what about the white COB I am planning to get?

Lemme know!

Hit up @BigSm0 , he will put you in the right direction.

 

[BigSm0]

I would go with 2 50 watt cobs before anything else. Not because I sell them but because even at 50 watts people see light stress. You will pay a bit more up front but well worth it in the end. I don't even think I'd run a 100 watter if it was free. That's my opinion and I'm sure numerous others here agree. I have also seen a few grows with 1 cob online and a close friend here who's first grow ever pulled a couple oz off of one.

 

[KonopCh]

If you look at my signature/journals, you'll see that I grew few plants under one CREE CXB3590.

 

[WalterW]

I have just about completed a grow with 2 x cobs @50W each
I have calculated a wet weight of 339g, and still have a bit of popcorn on the tree and gifted a main cola and few samples to some people which I didnt even take into consideration when doing the wet weights.
dry. should be about 75g - so that is 0.75gpw for a complete noobie using the cheapest of cheap stuff

 

[Rusty_Shackleford]

I use 6 cxb3590 at 1500 mah (roughly 50 watts a piece) in a 4X2 and it's perfect. So for a small tent (like a 2X2) I'd run three for maximum yields. Or lst a bit and contain the plant in a smaller area and run two. IMO one may be a little short on power. Edit - at that wattage I

 

[Mr.Sparkle]

Well really comes down to how big a plant you want to grow or how much, as that dictates how much light you need.

Now tech wise i'm gonna presume your referring to the 100w eBay cobs, now with those there isn't a difference between the 100w vs 50w or even possibly the 30 watters, what makes them difference is they are run at different current ratings giving different wattage's but the cob is the same, now as stated above by @Prophetiko with LED's in general no matter what the led is, it will be more efficient if under driven as in run with less current, so say in your application 2 of the cobs running at 50w vs one running at 100w, the two will actually put out more light, plus you get the benefit of having two sources of light instead of a singular source which will run hotter, affecting how close you can get them to the plant/plants.

Now running say 4 at 25w would be even better but it all depends on what you want to do.

For ease if only talking about 100w of power usage or so, i honestly suggest just going out and getting some screw in 14ish watt led screw in bulbs and just pop the domes off, and pick up some light cleats, as for efficiency vs cost and ease, 8 of those will out pace any of those ebay 100w or 50w cobs easily watt for watt, and they are easily replaceable if needed.

But again kinda comes down to how much are you looking to grow per cycle, which actually dictates what you should be running for light and space.

As for the how close question, that is dictated by how hot or somewhat proportionally how much wattage each cob is consuming, less wattage equals, closer, more wattage equals further away.