Growing under COB

[Dorchid]

Anyone growing under COBs? I’m sure there’s a thread here but having trouble with the search function.

---------- Post added at 11:17 PM ---------- Previous post was at 09:19 PM ----------

I’m using some now dated cree cxa3070s. Running four atm. Seem to be doing a pretty good job but have only just set this up.




8 days growth on this phal

[Ray]

I am experimenting with a 50 watt COB LED. Damn it's bright! So bright that I'm afraid to put plants under it.

[Dorchid]

They’re bright for sure. I’m running them half powered at 1400mA which comes out to around 50 watts to each cob. The ctna went a bit red on some new growth when I put it under them but seems to have adjusted. The new growth on the phals is dark red so they may be getting a bit much and I may lower them, but they’re showing explosive growth. Currently the light is about 2 feet above the plants. These run fairly cool considering the light they produce...they keep the tent around 74F in a 65F basement. Also, have them on for 15hrs a day so may back that down as well.

[Connie Star]

What are COBs? I'm still using T5s for my lighted shelf and considering other options. Are they a type of LEDs?

[Dorchid]

It stands for Chip On Board. They’re essentially a light emitting surface with tons of leds packed together. They’re typically used for high bay and flood lighting but have recently gained traction as grow lights due to their high efficiency. These particular COBs put out something like 9,000-11,000 lumens at full power and it’s directional unlike fluorescent which throws photons in all directions. They’re also extremely efficient so the majority of the energy used is converted to light instead of heat as with HID lighting. You can order kits or build your own. I put these together for around $120 each...that includes 2 COBs, heat sink and driver (actively cooled with second hand cpu fans).

[Connie Star]

So there essentially LEDs?

[Dorchid]

Yep. Just a different format. Basically a bunch of leds packed together.

[thefish1337]

i've got a 180 watt cob setup. the problem with cobs is their spread. they are really strong at their center, be gentle or you might damage your plants while adjusting for proper light.

[Dorchid]

For sure. If building your own you can drive them at lower power to reduce the intensity if needed. I’ve got a fair amount of coverage with these and can space them out if needed with higher light orchids getting the brunt with lower light types on the perimeter or farther away from the fixtures. What kind are you running and how many COBs?

[thefish1337]

Originally Posted by Dorchid

For sure. If building your own you can drive them at lower power to reduce the intensity if needed. I’ve got a fair amount of coverage with these and can space them out if needed with higher light orchids getting the brunt with lower light types on the perimeter or farther away from the fixtures. What kind are you running and how many COBs?

2 creecxb3590s run around 70-90 watts each I adjust with a dimmer. I hang it high and grow a plumeria tree, some cacti and some orchids under it.

I like the samsung mid power chips like horticulture lighting group sells as well. I think orchids really do well with medium intensity diffused light which the boards provide better than cobs.