How has the transition to COB lights effected your grow style?

[PerroVerde]

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[captainmorgan]

GG#4 can lockout with too much calcium. If your not watering too heavy you may want to try a Epsom salt foliar spray.

 

[Humanrob]

GG#4 can lockout with too much calcium. If your not watering too heavy you may want to try a Epsom salt foliar spray.

Thanks Capt, I'll look into it.

 

[Humanrob]

While I truly appreciate the help, I did not intend to make this into a "diagnose my plant problem" thread.

I am interested in the overall differences and subsequent changes people made after transitioning to COB lighting...

 

[medicinehuman]

It's a learning curve for sure, but well worth it with the right lights.

 

[JimmyIndica]

I always keep cal-mag jug full and 5.8 ph

 

[KarmaPaymentPlan]

With the light source lacking infrared and greatly upsetting the way a plant naturally functions with water and nutrient uptake, I can not for the life of me see why anyone who is into "organic" or "natural" or the whole "ROLS" thing would even consider using cob's or led at all for that matter.
If you are looking for things to happen as natural as possible this is clearly not the ticket.
Now if your just the mad scientist type as I tend to be, then maybe these could be for you

that's pretty bold my plants have been doing fine in recycled dirt under cobs i have to spray some Epsom probably one a month but it's pretty effortless. I will admit the fabric pots help a lot with drying out the medium but if my environment is in check i water every couple of days and I'm happier knowing my top soil isn't fried from ir keeping my microbes happy. It's hard to burn with organics so as long as your well amended your plants will be healthy. No ph or ppm balancing for me

 

[SupraSPL]

I have been using ROLS for years. When I switched to COBs and increased PPFD, right away in veg I noticed hungrier plants in general. I do agree with the theory that it will reveal problems with soil fertility. The way I addressed it was by increasing fertility of the soil mixture and potting up earlier. Since then all I have noticed is faster healthy growth

 

[Rahz]

My transition was from CFL to LED (Vero version1 nominal current at 65C). CFL produced about .65 GPW. VeroV1 has produced 1.1 - 1.2 GPW. In the final stages of cure ATM... looks like it will be close to 1.25 this time around which I'm very happy with. Vero version 1 is what, about 37% efficient at nominal current?

Taking my yield with Vero1 efficiency and translating it to CXB3590 @1.4 amps yield would be 1.8 GPW.

 

[Humanrob]

I have been using ROLS for years. When I switched to COBs and increased PPFD, right away in veg I noticed hungrier plants in general. I do agree with the theory that it will reveal problems with soil fertility. The way I addressed it was by increasing fertility of the soil mixture and potting up earlier. Since then all I have noticed is faster healthy growth
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I would love to see the underside... the "plants eye view" so to speak, of that light array! I'm sure there is no way to photograph it while the plants are there, but its hard to imagine what the light spacing looks like from all those individual heat sinks. Its definitely working though!

Not sure what you mean by "potting up earlier"?

 

[Rahz]

To answer the questions in the OP, Identical strains in hydro/soil the hydro was much healthier and frosty, better yield too of course... but then again I'm not a soil expert.

Overall I haven't noticed nutrient issues, though a friend killed some plants moving them from HPS to LED half way through veg, though I suspect there were other issues going on.

 

[SupraSPL]

I would love to see the underside... the "plants eye view" so to speak, of that light array! I'm sure there is no way to photograph it while the plants are there, but its hard to imagine what the light spacing looks like from all those individual heat sinks. Its definitely working though!

Not sure what you mean by "potting up earlier"?

That is a good question, next time I am swapping out batches I will try to get a pic from that perspective, would be interesting to see the spread. I adjust each heatsink depending on the canopy so it changes a bit each time.

I usually pot up a few times and the final size is a 5 gal bucket. With higher PPFD I noticed they were running out of food more quickly so I would pot up sooner than I used to. If I let them go too long without potting up and they are in the direct light I notice yellowing and even burning from deficiency.

 

[mc130p]

I start a full feeding regimen on the second set of leaves from the seedlings...a bit earlier than I used to...one thing I did notice, like was said earlier, that the problems really blow up quickly with such high growth rates. I used to kind of wait until the plants looked a little 'hungry,' but if I do that now, it seems like it's already too late and I'll get yellowing. Part of it might be the tiny pots/large plants, but that wouldn't be such the case without the cobs, so they're all interrelated.

 

[churchhaze]

I start a full feeding regimen on the second set of leaves from the seedlings...a bit earlier than I used to...one thing I did notice, like was said earlier, that the problems really blow up quickly with such high growth rates. I used to kind of wait until the plants looked a little 'hungry,' but if I do that now, it seems like it's already too late and I'll get yellowing. Part of it might be the tiny pots/large plants, but that wouldn't be such the case without the cobs, so they're all interrelated.

I have this problem with fast growth in general. Whenever I make a mistake (wait too long to change nutes), growth crashes and leaves get yellow stripes, etc. It's sort of paradoxical because the more you do to increase growth speed, the more likely it is to crash if you make a mistake.

Of course I tend to have a low ppfd (500umol/s/m^2), around 12-14W PAR per square foot, so high ppfd isn't usually my issue.

Edit: To answer the threads question a bit better, one of the things I do different with cobs over HPS is that I tend to use lower ppfd now. (might change in the future/winter) I used to use 800W HPS in ~16sqft.

 

[grouch]

Is it possible that the plants need higher co2 levels to match the faster growth? In the planted aquarium hobby you can't run high power lights without co2 supplementation or the plants growth will stall out. Having plenty of food water and light will only go so far if the plant doesn't have enough co2 to match.

 

[SupraSPL]

I have been running a steady 800-900 PPM CO2 for the past few months, canopy temps 75-78F. During the summer it was steady 1500 PPM and canopy temps 78-82F. I still had some plants that got hungry in veg in both cases. That said, if a grow room is getting low in CO2 (~200-300) I would not be surprised if that caused some issues when using high intensity light.

 

[Stephenj37826]

Is it possible that the plants need higher co2 levels to match the faster growth? In the planted aquarium hobby you can't run high power lights without co2 supplementation or the plants growth will stall out. Having plenty of food water and light will only go so far if the plant doesn't have enough co2 to match.

Actually there is a table somewhere that shows figures of light intensity and CO2 supplementation.

 

[Stephenj37826]

Here is one. I had one saved on my now dead laptop that's better.


It seems as light intensity goes up the affects of higher co2 levels are magnified.

 

[p4id]

One thing I might have to do this Winter, using COBs, is to add heat !
Evaporation through the leaves is certainly less than HID, again due to reduced heat.
In 30 years under HIDS I have never used epsom salts or cal + mag. But now find I need it
for practically every water.

 

[Humanrob]

That was my first thought as well. Maybe some botanicare cal-mag + . I'm still leaning towards a general deficiency though. Purple stems all the way down to the soil.

Just to clarify, is the purple stems a sign of cal-mag deficiency, a different deficiency... or nute lockout?