In the flower room last night and just sharing some observations and opinions on what I've seen so far using COBs in one half and CMH on the other.
First I took a step back and thought wholly crap that's a lot of footprint for 615w. 300w of COBs and 315w of CMH covering 3x8.5'. Try that with a 600w hps bulb
The other thing that stood out while I was watering the plants under the COBs was the smell coming off the Blue Ripper 2 pheno. I know smell is subjective but I've noticed this before under COBs in my 2x2 tent and I've run this BR pheno enough times to know how it smells. Normally at this point I'd be sticking my nose into the flowers to catch a good whiff of the terps. But last night I was just bending down to stick the watering can nozzle into the pot and it was like a wave of that blueberry perfume smell hit me in the face. Not sure why it is but COBs enhance/bring out the terps which was one of the big reasons I wanted to run some COBs in this room.
I'd previously mentioned to consider the environmental effects associated with running COBs. Particularly an all-COB room when switching from hps or CMH. I quantified my thoughts on this which is the heat/RH factor and how it can affect RH in particular. Temps haven't changed much, overall temp in the room is ~1.5 to 2F lower but RH had been averaging 5% higher before adjustments and I had to tweak my inbound and exhaust to lower it. Then I threw in the new batch of 5x 3gal + 3x 5gal that were in there, totalling 30gal of medium in the room and more in line with the capacity/coverage I can run in there with this combination of lighting. I had to make further adjustments which I didn't have to do the odd time I had run the same amount of medium under 2x LEC's, RH jumped another 5% when I threw the new batch in.
Last thing I'll mention is the difference in maturity compared to CMH. No complaints or much difference in overall growth after about week 3 (CMH seems to have a greater effect on them through stretch, likely due to the colour temp differences of my veg lights). Overall growth now heading towards week 6 is closer. But maturity is definitely behind still and I'd expect to see them go 4-6 days longer. Buds are building/fattening well, just not maturing as fast, hairs are primarily still white whereas under CMH at this point I'd be seeing more mature hairs.
Enough chat, some pics of the Blue Ripper 2 pheno at Day 38 under the COBs:
Cheers