The COB effect...

Moflow said:

I also have noticed less stretch with cxb3590s 3500k compared to HPS which suits me fine as I've low roof height .
I'm still not dialled into the cobs but I'm getting good results and expect to do better as I fine tune my new set up
I think I force the plants to stay short due to so much light.
With the strain I'm running now I see less leaf under the cobs.

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I think that is the case too, too much light possibly and maybe if i alter the height of the lights and figure out whats best i might get the results i am looking for. Only problem is i have no easy way to raise/lower lights, especially with the plant scrog and the tent being pushed into a corner of a wall, leaves me only access via the front door, i cannot reach the lanyard release to lower the lights if i raise too high. I do have a dimmer hooked up to the drivers, i guess theoretically it would work sorta the same way as raising the light, but i prefer to have the cobs working full blast as it keeps the temps exactly where they should be.

Fuck it I may cut the scrog net down, it was the first time doing a DTW coco run, and the stalk growth is UNREAL. Its like you cannot tame the plant at all, the net looks like a bubble about to burst.

Also i have this strain i am going to be running next that won't tolerate the LED room at all. I tried vegging this strain in there before i started the flowering of the AK and it was struggling badly, i choked it up to genetics, so i moved the plants under T5's and within days started to look great... i took clones blah blah blah, and put the mothers back into the flower room. Within days the plants went back to poop and started throwing off mutations so i chopped em down in fear they may herm and pollute my lady's.

If its not the LED its definitely humidity related, the flower room gets about 35-50% humidity veg room 75-90%. And considering this strain was bred on Vancouver island the humidity is fairly high on the island.

sixstring2112 said:

this was what led me to buying the 2700k 80 cri cree and they give just a few extra inches of stretch and finish just as nice as the 3000k and 3500k cobs. i know alot of guys use the 3500k because it has great veg ability but i dont need veg lights so i went a dif direction.

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So you just run 100% 2700k? i will have to check out some more 2700k grows. Maybe the lack of IR light causing less stretch, it would contribute to less heat which would then contribute to less stretching possibly. hmm

OrganicCanuck said:

So you just run 100% 2700k? i will have to check out some more 2700k grows. Maybe the lack of IR light causing less stretch, it would contribute to less heat which would then contribute to less stretching possibly. hmm

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I have different setups in different areas of my shop.but i like the 2700k setups best.my take on the stretch problem or lack of stretch is based on spectrum alone. 3500k cobs have way more blue in them then any hps lamp.most hps are around 2200k color temp and very low cri so lots of spikes at just a few colors.shitty really when you compare it to any cob led.the 2700k has alot more blue still but also has a better spike in the red spectrum which for flowering is good for a lil extra stretch.
Im vegging plants now with a 3000 k vero panel and those plants are every bit as nice n compact as my other plants under 6500k t5 lamps.cobs just have a more uniform and broader spectrum than most any other lamp except maybe lec/cmh lamps

OrganicCanuck said:

So you just run 100% 2700k? i will have to check out some more 2700k grows. Maybe the lack of IR light causing less stretch, it would contribute to less heat which would then contribute to less stretching possibly. hmm

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more blue light would reduce stretching. red light causes plant to "reach for the light" this is why MH,CMH and fluorescent grows are so short and bushy. even a 2700k would benefit from the addition of 660nm light to compensate for the deficiency of 435nm light

wonder if the "cob effect" has a psychological component?

sixstring2112 said:

I have different setups in different areas of my shop.but i like the 2700k setups best.my take on the stretch problem or lack of stretch is based on spectrum alone. 3500k cobs have way more blue in them then any hps lamp.most hps are around 2200k color temp and very low cri so lots of spikes at just a few colors.shitty really when you compare it to any cob led.the 2700k has alot more blue still but also has a better spike in the red spectrum which for flowering is good for a lil extra stretch.
Im vegging plants now with a 3000 k vero panel and those plants are every bit as nice n compact as my other plants under 6500k t5 lamps.cobs just have a more uniform and broader spectrum than most any other lamp except maybe lec/cmh lamps

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Im using one cxb3590 3000k at 1500ma for a veg light at moment and the plants look good.

sixstring2112 said:

are you a cattle rancher in montana ?

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Does It Count If I'm A Dental Floss Tycoon

OrganicCanuck said:

I have been running cobs for a while now, and i am still on the fence about them. I am running same as most people 3500k with a few 3000K, 3590s.

As said earlier in this thread, they grow plants, buds are rock fucking hard so something is good about the spectrum regards to that. My concern is the lack of stretch, you must be thinking really lack of stretch ? that's a good thing no? Well to some extent, i just find the plants stay too short and produce intolerable amounts of leaves, this could just be the learning curve to figuring out what is the best parameters to use. Not even the AK i got in flower now would stretch. That is my only issue so far. The ultimate test for me would be a 100% sativa : )

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For the record, I am doing my first grow with COBs and I am experiencing the same issue -- no stretch and super dense amounts of leaves.

I haven't flowered yet so I don't know how much of a change that will add.

Here are my sativas (NL#5 x Haze) at end of week 6 from seed:




Indicas on the right (Afghan Kush, World of seeds) Also end of week 6 from seed

Is it possible the plants are in some kind of "saturation" and a reducing of the light might help? 50W of a single cxb3590 goes a long way, perhaps any lack of stretch might be helped by reducing the power or increasing the distance between canopy and source.

CannaBruh said:

Is it possible the plants are in some kind of "saturation" and a reducing of the light might help? 50W of a single cxb3590 goes a long way, perhaps any lack of stretch might be helped by reducing the power or increasing the distance between canopy and source.

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I have raised and dimmed lights previously with still extreme tight node spacing. From what i have been reading by adding FAR RED spectrum or even running 2700K cobs helps gain the stretch we all desire. Too bad i don't have the funds currently to upgrade my light, otherwise i would definitely experiment more.

And i would love to post more pics but i am having a hell of a time trying to get any pics to upload successfully. Is there a maximum allowable MB requirement or whats the deal? Sometimes my pics will upload but will not display as an image for everyone to see but as a clickable link.

I've had the same thought, 730nm is well known for causing stretch. There is no reason a person couldn't use it to help achieve the amount of stretch desired.

OrganicCanuck said:

I have raised and dimmed lights previously with still extreme tight node spacing. From what i have been reading by adding FAR RED spectrum or even running 2700K cobs helps gain the stretch we all desire. Too bad i don't have the funds currently to upgrade my light, otherwise i would definitely experiment more.

And i would love to post more pics but i am having a hell of a time trying to get any pics to upload successfully. Is there a maximum allowable MB requirement or whats the deal? Sometimes my pics will upload but will not display as an image for everyone to see but as a clickable link.

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Are you using a phone to upload the pics or a computer? Sometimes i have the same issue from my phone if im not using a wifi connection.

Some of my plants stretched 36" in 11 days and some of my plants haven't stretched more than 12" the whole flower cycle. These plants are literally side by side. This was with 3500K COBs.

I have gotten more growth in apparently shaded areas and leaves remaining green in very deep apparent shade. I first noticed it with my a51s but multiple COBs take that to way different level. Been using some COBs well over a year and do notice trich formation becomes apparent days sooner and it seems everything under good leds or COBs is going to be frosty, even if that strain may not have been so in the past.

sixstring2112 said:

Are you using a phone to upload the pics or a computer? Sometimes i have the same issue from my phone if im not using a wifi connection.

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I take photos with phone then i upload to computer to remove image details. It only seems to happen with images from this phone, my old photos from many many moons ago will upload. So that led me to believe must be image size, but i have viewed many high definition images on riu. I will set my camera to 8mp tonight and try lowest quality setting.

Hopefully i get some more photos going here and there.

jillxjilly said:

For the record, I am doing my first grow with COBs and I am experiencing the same issue -- no stretch and super dense amounts of leaves.

I haven't flowered yet so I don't know how much of a change that will add.

Here are my sativas (NL#5 x Haze) at end of week 6 from seed:

Indicas on the right (Afghan Kush, World of seeds) Also end of week 6 from seed

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Hey my plants did the same thing did you have better luck on your next grow? Sorry I know this is an old thread just wondering.