The COB effect...

So just finished my first run with COBs. Even though i got lazy with watering and locked out my girls from nute uptake with salt build up (reducing my yield by at least 40%) i saw enough "performance" from them to become an HPS convert. I doubt i will ever use my HPS lights again. My second cob run is underway...

Speaking of performance, however... i noticed some very distinct changes to the plant under COB. As i was told, the nugs were rock solid. And not just at the top. Even the "larf" at the bottom of the plants turned out rock hard (my plants were 4 footers in tomato cages). Also, as reported, the resin production was out of this world, in both quality and quantity. Although, my bud yield was 40% less as i said, my dry ice yield for hash from the trim was almost double (not a single lower nug was put into the trim pile). Resin coated the spear leaves so much that the leaves got twisted right up. Amazing...

So the rumours i found to be true. And im convert. But this isnt what i wanted to talk about.

I want to talk about the effect that the COB light has on the plant.

My observations... the COB light made the fan leaves very... durable, thicker, less pliable, heavier. They were like fan leaves that come from grows that use a lot of silica. Deep, dark, shiny leaves. Heavy. So i wonder... how/what/why is the cob light doing that? Is it forcing uptake of nutes at a different rate? Changing the proportion of nutes being took up?

Any ideas?

At any rate, it seems like the COBs produce a stronger cellular structure in leaves, stem, stalks... all around. This appears be true of the flowers as well. And it would explain the density/weight of nugs that would appear to lighter than they should be.

Also, given that the resin is to protect the flower from harmful frequencies of light (uv and etc) can it be assumed that increased resin production under COB light suggests that COB light is somehow harmful?

Your thoughts, please...

Starting trouble huh

My take is the lack of ir light makes for less stress and coupled with a better spectrum than hps we end up with nutrient hungry plants that are just way more healthy than we are used to so the leaf mass is better/thicker/greener.idk but on the cut of mk i been running for years it is a no brainer the cobs are producing harder and healthier buds with lots of resin.it makes me think the whole "uv light stresses plants to create trichomes"is a load of crap someone made up and we all just went alongwith it lol.

The whole plant can look different, I've given cuts to friends that run HPS and grow outdoor and their plants can look like a completely different strain.

I had several runs of this mk under my Mars 1600 which is 760w at the wall (240v) and that panel supposedly has lots of different leds including fr and ir and yeah it was good but did not cover as much area as 525w of cobs,did not have as good bud development down low like hps or cobs and was every bit as hot as any 600w hid i ever ran.plus it started burning out strings of leds @ 14 months.

dandyrandy said:

Starting trouble huh

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How so?

sixstring2112 said:

My take is the lack of ir light makes for less stress and coupled with a better spectrum than hps we end up with nutrient hungry plants that are just way more healthy than we are used to so the leaf mass is better/thicker/greener.idk but on the cut of mk i been running for years it is a no brainer the cobs are producing harder and healthier buds with lots of resin.it makes me think the whole "uv light stresses plants to create trichomes"is a load of crap someone made up and we all just went alongwith it lol.

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It's not crap. The university of Utah has proven that a fuller spectrum including 50% blue light to red will enhance plant health and vigor.

And uv added can increase thc content up to 4%.

There are commercial medical growers who have tested and confirmed these results as well.

And in my opinion adding the 315 LEC to my Hortilux HPS room has increased quality noticably and helped keep plants healthier to the end already.

This added a bit of uv and a way more sun like spectrum to the flower room.

sixstring2112 said:

My take is the lack of ir light makes for less stress and coupled with a better spectrum than hps we end up with nutrient hungry plants that are just way more healthy than we are used to so the leaf mass is better/thicker/greener.idk but on the cut of mk i been running for years it is a no brainer the cobs are producing harder and healthier buds with lots of resin.it makes me think the whole "uv light stresses plants to create trichomes"is a load of crap someone made up and we all just went alongwith it lol.

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So as i said...i have done just one run.... little experience with the cobs... so... they seem to want more nutes thats for sure. But how much? I realize that is strain dependant, but in general would you same 20% more nutes or 30% or??? Can you ballpark?

Gquebed said:

How so?

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It can be a bit touchy to some. I don't know. I have only used cobs. So I can't say. I know I can't complain. Except this time of year it's a bit cool for my cobs. I may have to add heat.

MichiganMedGrower said:

It's not crap. The university of Utah has proven that a fuller spectrum including 50% blue light to red will enhance plant health and vigor.

And uv added can increase thc content up to 4%.

There are commercial medical growers who have tested and confirmed these results as well.

And in my opinion adding the 315 LEC to my Hortilux HPS room has increased quality noticably and helped keep plants healthier to the end already.

This added a bit of uv and a way more sun like spectrum to the flower room.

Click to expand...

Easy bro,just thinking out loud lol.i run 50%hps and 50% mh in flower for years now and have 3 or 4 dif color tubes in my t5 setups for veg.all im saying is a cut i have been running 7 years now all the sudden patients are asking shit like,what did you do to the mk she came out awesome last batch i got,or damn bro the last batch of mk knocked my dick in the dirt.this was the crop before i added the uv lamps in with the cobs.in theory they should be blown away by this next batch with uv added and far red ?

dandyrandy said:

It can be a bit touchy to some. I don't know. I have only used cobs. So I can't say. I know I can't complain. Except this time of year it's a bit cool for my cobs. I may have to add heat.

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Well... i just know what i have experienced in the switch.

It really isnt my intention to stir up a debate about which is better. Im intetested in a discussion about the differences people have noticed in growing with cobs and how/why those differences come to be...

Gquebed said:

So as i said...i have done just one run.... little experience with the cobs... so... they seem to want more nutes thats for sure. But how much? I realize that is strain dependant, but in general would you same 20% more nutes or 30% or??? Can you ballpark?

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It's very strain dependent but most of my strains just needed more cal or mag or both and not just upping ppm.

Someone just posted a pdf from Cree about horticultural leds vs hps. It claims that 15% of the light from an hps is emitted as IR. I see lots of posts about cobs being supplemented but never with Infrared.


That can't be healthy. Any sane person would rather have that energy directed at red or blue.

Gquebed said:

So as i said...i have done just one run.... little experience with the cobs... so... they seem to want more nutes thats for sure. But how much? I realize that is strain dependant, but in general would you same 20% more nutes or 30% or??? Can you ballpark?

Click to expand...

For me bumping from 500ppm to 700-750ppm has done the trick
First run under cobs i used my normal feeds of 500 to 600 mostly 500ppm and was constantly chasing deficiencies and using calmag to correct them.these past couple rounds with nutes bumped up i have no more need for the extra calmag.

sixstring2112 said:

Easy bro,just thinking out loud lol.i run 50%hps and 50% mh in flower for years now and have 3 or 4 dif color tubes in my t5 setups for veg.all im saying is a cut i have been running 7 years now all the sudden patients are asking shit like,what did you do to the mk she came out awesome last batch i got,or damn bro the last batch of mk knocked my dick in the dirt.this was the crop before i added the uv lamps in with the cobs.in theory they should be blown away by this next batch with uv added and far red ?

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I didn't mean to come off argumentative. I was agreeing that the spectrum makes a huge difference.

I did not know the cobs made more of a difference than your previous attempts though. Interesting.

All I know is they do make solid buds. 700w of 3590's are amazing.

MichiganMedGrower said:

I didn't mean to come off argumentative. I was agreeing that the spectrum makes a huge difference.

I did not know the cobs made more of a difference than your previous attempts though. Interesting.

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Yeah its really blowing my mind to think how these lil 35w cobs are doing so well with an obvious lack of certain spectrums we all learned were important. The reason i run the hps/mh combo was for broader spectrum and that added uv the mh has.but hell im pulling more weight and better quality from almost half the power on the cob side of my shop.
Im in the process of building out a new shop/grow op now and i had planned on using all gavita lamps in there and fitting them with 50/50 hps and mh like my current rooms.but now im not even sure i will have any hid in flower lol.
Im def making plans to veg under cobs as well or maybe these damn quantum boards if i ever figure them out

captainmorgan said:

It's very strain dependent but most of my strains just needed more cal or mag or both and not just upping ppm.

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Hmmmm.... before my lockout issue i figured i should up the cal/mag too... but i start with water thats loaded with cal... out of the tap at 250ppm... would you suggest i supplement that?

sixstring2112 said:

For me bumping from 500ppm to 700-750ppm has done the trick
First run under cobs i used my normal feeds of 500 to 600 mostly 500ppm and was constantly chasing deficiencies and using calmag to correct them.these past couple rounds with nutes bumped up i have no more need for the extra calmag.

Click to expand...

Don you know what ppm your water starts at? Or are you RO?

Gquebed said:

Hmmmm.... before my lockout issue i figured i should up the cal/mag too... but i start with water thats loaded with cal... out of the tap at 250ppm... would you suggest i supplement that?

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I always use RO water and watch out for too much cal, it can cause lockouts. Maybe just mag for you.