Are cobs worth it?

Hanfred said:
Ive just replaced my old 150W MH with 4x Cobs 5000K with poti, and problems started. Plants became extremly bushy and yellow small leafs. So if youre so clever tell me what errors did I made
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sounds deficient and rootbound.....but getting nitrogen if extremely bushy....kind of a kwandry
 
Hanfred said:
Ive just replaced my old 150W MH with 4x Cobs 5000K with poti, and problems started. Plants became extremly bushy and yellow small leafs. So if youre so clever tell me what errors did I made
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What cobs, what wattage, what space?
 
Hanfred said:
Ive just replaced my old 150W MH with 4x Cobs 5000K with poti, and problems started. Plants became extremly bushy and yellow small leafs. So if youre so clever tell me what errors did I made
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how much cob wattage? did you use a light meter?
 
Hanfred said:
Ive just replaced my old 150W MH with 4x Cobs 5000K with poti, and problems started. Plants became extremly bushy and yellow small leafs. So if youre so clever tell me what errors did I made
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If I were to venture a couple guesses 1. Shocked the plants by essentially doubling the light 2. Did not up the feeds to accommodate 3. Did not supplement additional Ca and Mg that are common to become deficient in a lot of strains under led in comparison with an hid fixture.
 
gk skunky said:
If I were to venture a couple guesses 1. Shocked the plants by essentially doubling the light 2. Did not up the feeds to accommodate 3. Did not supplement additional Ca and Mg that are common to become deficient in a lot of strains under led in comparison with an hid fixture.
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Thank you for the advice I'll follow. I thought if I take a little more fertilizer, it already fits. My neighbor is also a grower, he has a half-empty bottle: "Aptus CaMG Booster". On the bottle stands for 3. and 5. week of flower,is that ok? And sorry for my bad Englisch :)
 
That Aptus CaMg is good, concentrated too so be careful. Also stupid expensive stuff but hey, if you can get it from your neighbor...
 
sethimus said:
are you slow or something? i tried to criticize the op for making claims without backing them. I DO know that cobs are worth it, i want to see said video in which those claims are originating from. how hard is that to understand, like srsly?
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No sethimus I'm not slow....just adding some input on successful COB grows, thought that was the idea of this site!
 
My plants always bushed out, from CFL to LED 3000-3500K. Some strains more so than others but I don't see high K being all that beneficial at any stage using LED. I learned to prune from week 2 of veg til about week 3 of flower so I didn't end up with much pop corn or too many colas. Over time I learned to flip early, about 3 weeks to fill a single plant in a 30x30 area. Not at flip but a couple weeks into 12/12 the area is full and I would still end up with around 2 feet of height above the screen as long as it's not straight Indica. Seems like a good thing.

One day I hope to play around with the schedule some more and see how big a plant can get with 1-2 weeks veg.
 
Bill Lidgate said:
Maybe COBs aren't worth the bother!
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To put some flesh on the bones of the argument for LED strip with small LEDs vs Big hot COBS, check this

27161357812_81909a73b8_b.jpg

this is a LED strip, made by Samsung and in stock at Digikey (SL-B8T7N90L1WW about $30), which can be paired with the currently cheap Mean Well HLG-185H-48A at BG Micro ($23) and built into a 2 strip "wing" that is 44" x 1.6" at ~120w / 18,200 Lm.

Filling an illumination area of 44" x 44" somewhat like the BML/Fluence SPYDRx (5 wings, $900, 300W) or SPYDRx Plus (8 wings, $1500, 600W)* can be done with this combo for about $400 and $575 respectively for the LEDs and power supplies, but producing substantially more power (665W and 1000W). Even with the additional expense of very nice framing and mechanicals the total price should be quite reasonable. The 8 wing version should have the energy cost of a 1000w HPS but allow much higher PARS ( with closer placement) and a much larger and more even illumination area.

The extreme setups with >8 wings will require fans or something more sophisticated to cool and the illumination levels are substantially higher than Sol, so included here just to show the cost decreases at higher volumes. The ~$1820 / 28 wing setup could be used to illuminate a 5 sq meter area (7' x 7') at a Sol like 100,000 Lm per sq meter.

*SPYDRx W/$ = 0.333, SPYDRx Plus W/$ = 0.4
 
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The Samsung SL-B8T7N90L1WW strip at 66.5W has a 12 fold larger surface area to dump its heat than the 79.8W Vero 29, and its W/square mm is 14 fold lower! This means the strip LED is much easier to run cool without heroic (and expensive) effort. The Samsung strip has 96 LEDs each running at ~690 mW and must be screwed down, no wimpy foam tape is going to work at this power!
 
Rahz said:
If someone can't pull at least 1.4 - 1.5 GPW using current cob technology they don't know what they are doing. I have a lamp using Vero 29 version 1 running at 40% efficiency, about 125 LPW. 3500K 80 CRI. The minimum I have pulled from it is 1.35 GPW and the best has been 1.68 GPW. That's 21 ounces from a 350w output lamp in 10 square feet, almost 60 g/ft. That doesn't include several Os of lower branch popcorn.

I have another lamp, my first one, using Vero v1 at nominal current. That's about 36% efficiency, 115 LPW in theory except for the fact that the Tj ran hot, about 65C, and it consistently achieved 1.25 GPW. 80 CRI, Kelvin averaging out to 3350.
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I am thinking about starting to build a cob setup. Do you think it matters if I go with Vero cobs or Cree cobs. I have been researching cobs and the Cree cobs are more spendy then the Vero cobs. Is there a real difference in output aka yeilds besides the price difference?
 
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