Apologies for the book but thought I'd post some random thoughts related to lighting/heat as I'm more than 1/2 way through this run, and before I forget them sampling several harvests I'm pulling. Outdoor is ready to hang/dry, have a pregnant JTR drying now, Sunday I pull a pregnant PPP, and I'm 2 1/2 weeks out from pulling the JTR in the 3x3', wholly weed batman! The reserves (and payback for all the money I've spent lately!) are stacking up nicely
All comments/thoughts/experiences are more than welcome...
First off, these CMH rigs are awesome, fast flowering, low heat (running 2 of the LEC Sun Systems now in a 4'x9.5'x7'H room), low power consumption. Not much bad to say. There are a couple of things that need adjustments to get the best out of them though. I'm not seeing any reason to go smaller than 3x3 for footprint, awesome coverage for 315w. Will be looking for an opportunity to get a 240v circuit in there in the next few months to gain even more efficiency. But I have no regrets on running the 120v units, if this is inefficient, bring it on!
a) Have to test (next run and the Blue Dream I'm running under the new LEC for a few days) moving the light up further, going to run them @22" for the Blue Dream and next 3x3 or so. The PPP strain is getting stressed from the intensity. The JTR's like it fine @20". It's a fine balance between height and final yield so I'm leaving the 3x3 (PPP/JTR) alone at 20" for now since I have a reference with both strains from the first run. Although PPP got the same light stress first round, it produced very well in the end and no bud burn, just the leaves.
b) Related to a) and both a benefit and problem with some strains. imo, part of the reason these lights do well is the intensity and heat directly below the lights or top of the canopy. They haven't increased the overall room temps, you can set a beer on top of the unit while doing maintenance and it won't get warm. But you can feel the heat directly above the canopy which is where some of the stress showing on PPP is coming from. At the same time, the intensity and heat on the top canopy I think helps with crazy fast bud growth and density (will explain why in point c). Some strains, like this PPP may not like it, whereas JTR is looking like a 3.5-4 oz plant and after almost 5 weeks has 1 or 2 leaves with some slight bleaching. Both are Sat-dom and ~70% sat genes.
c) Related to b) but not CMH specific. I unwittingly got a huge yield bump, and similar bump in density recently in my breeding tent. I did a couple of runs in that tent with the 3000k 200W LED COB spot light I picked up several months ago for this purpose. The LG LED's just weren't cutting it, fluff, not as many seeds as I could have gotten so I bought a $165 200W (4x 50W) COB light on Alibaba. The build quality was horrendous, wasn't expecting anything different really, yet the basic build/components fared much better than the LG LED's, pretty well doubled my yield instantly and got a bunch more/larger seeds. I took the thing apart as soon as I got it, secured the drivers (the original drivers had come loose during shipping, speaks to Chinese QA #@$!), removed the lens and fired it up in the tent. instantly got a huge yield and density increase over the LG LED's. But they were still just "OK", not bad for the price and better/cheaper than the LG LED's. Then this last round, I started the round mid-summer and in the basement. Since it was summer and the air conditioning was running, temps were low in the tent. Instead of trying to heat it, I grabbed my GP-1000 DIY panel I'd built last year for CFL's, stuck 6x 13w CFL's in it and added it on an angle towards the canopy. Had to remove 3 CFL's and replaced them with 10w LED bulbs to get the temps consistently at 80F. WOW is all I can say, I just pulled the JTR from that tent and considering the size of the plant I would have gotten maybe 3/4 oz dry with the LG LED's, 1 1/4 with the COB spot light. It'll pull at least 2 oz dry with this current setup. That's from a low/medium yield strain and relatively small plant. The density feels similar to what I'm seeing with the CMH. So back to my thoughts on WHY this happened. imo, the additional mixed spectrum from the 3000k COB's, 2700k CFL's and 4000k LED bulbs (all white light btw) will have been a factor, an interesting factor when designing COB builds? But also, the COB spot light throws some heat directly below the light and because these plants weren't originally going into the tent, they were much bigger, even tied down than I would normally run in this tent. The tops were ~8" - 10"below the light and the main colas on both plants were within 3-4" (until they bent down with the weight!). The last notable factor with this accidental rig is that the JTR plant I just pulled is the frostiest I've grown in about 4 rounds under different light setups
Based on this "accident", I'm going to try replicating it next round. I'll be running the COB light close to the top of the canopy 8-10" and will keep my DIY fixture with the CFL/LED bulbs angled towards the canopy. The run after I'll remove the CFL's and see what happens. Going to be difficult to prove out which factor is which without controls so I'll try to run a couple of known strains in there. Whichever factor or combination of factors did this idk, but the difference is crazy, worth investigating this further. One thing for sure is I have to get those DIY 3070 COB's built and mix them with the CMH, that I'm pretty sure will be the Nirvana of indoor lighting...
Cheers