Flower times with COBs vs....

Hey guys, I have noticed several members on several boards talking about shorter flower times with COBs. Has this been documented, any side by side comparisons or what? I am on day 36 flower but (a) just got back growing after a LONG hiatus, (b) never grew this strain and (c) never grew with COBs before this grow ever so I have nothing to compare to.

People talk of 50 day flower periods, can it be true with normal 60-70 day strains?

I noticed it slightly from clones, not really finishing faster, just the trichromes turning a little quicker but idk if that's the plant technically finishing faster. From seed? The "breeder," often doesn't know themselves lol

I have been thinking it has a lot to do with canopy temps. HPS emits an 825nm spike of infrared radiant heat that may raise the temp in the buds, causing a fluffier bud and extended flowering (smix of mature and immature calyxs). Higher temps should also result in a higher yield on the scale if CO2 level, water and nutrient availability was sufficient.

Ace of Spades run with warmer canopy temp (~82-85f with bare 600W HPS) Great bud but fluffy and slow/sloppy finish.


Same Ace cutting under HPS with a cooler winter finish. The buds that were shaded have noticeably more color.


Same Ace cutting run under LED with canopy temps (75-78f) Fast clean finish, more ice, more flavor, increased density. One of the most popular smokes I have.



A friend (HPS grower) gave me a selected cutting and said it was an 11 week finish but good yield. Normally I would not run something like that but I suspected I could get it to finish quicker and wanted to give it a shot. Glad I did, finished in 58 days under the COBs with a nice clean finish and amazing flavor (looking for a pic). Just ran that same cutting under COBs and tried to bump the canopy temp up to about 80f (cool summer finish). Here she is at 57 days, probably pull her out of the flower tent in a few more days and then sit a few days in the dark.

Ive noticed on some strains 48hrs hours 12/12 and there throwing pistils allover shorten transition maybe little? and some strains have ripened a bit sooner than expected!

Those plants look great Supra!

Jimmy, I noticed my clones threw pistils within the first few days as well. I just thought it was due to them being taken from an older plant that had already started staggering limbs.
I have a couple mother plants and their clones that are a week or two apart, I will be keeping an eye on them.

How about under a DE setup?

Well my rascal og's under hps seem to be just as far along as the ones underneath my diy led's. the only difference being and obvious weight difference. They have been 12/12 for 55 days, seems early to finish. I think I have 750w hps over 3x3 and roughly 210w led over 3x3. Next side by side I will double the watts of led and it should blow the hps out of the water. As far as pistil development the rascal threw pistil almost immediately but it took the woody kush's much longer. The ripening has been the same story, kinda opposite of what I thought going in.

Oh and thanks to all who've contributed to the led forums. I am getting around to posting my side by side.

I just chopped 3 SLH under cobs. Finished 2 weeks sooner than before under blurple. Much denser, much better flavor. I never have used hps. No idea why. Second run under cobs. These are clones. And the SSH clone I ran under the cobs is much frostier. Almost to strong for me. Under the blurple less potency. Anybody want to buy 4 300w 180 actual panels? I hate to toss them.

I will also mention that the plants under hps are showing all the uasual signs of nute deficiency whereas led plants are still green and healthy looking. May be side effects of light spectrum, all plants fed from same reservoir. So Dandy whats your cob setup, I got bridgy's, I'm super happy but need to run higher wattages.

I run 3 cobs on a "rail" 3 rails in a 46x42 inch area. Each rail is very light. Seperate dimable driver for each cob. Max of 900w approx. Pc coolers for heat sinks. Just grow for myself. I usually have several different strains. The 3 seperate bars let me adjust for different growth patterns. Last run SSH SLH and Blue Cheese.