New COB setup, plants not transpiring enough.

Faultyboy

Faultyboy

Active Member
Hello Everyone,

I've just recently switch my veg room over to COB LEDs from HPS. (24xVero29@1050mA over +-7sqm)

My plants are in 100% coco. While using HPS I could get away with feeding my plants daily once they had established a good root system.

Now with the new COB setup I can only feed them once maybe twice a week at most as they just aren't transpiring as much as they used to. Some plants are still showing signs of overwatering even on this schedule and they all look like they need more feeds to get their nutrient requirements.

I have just started testing a batch of plants in 50/50 coco and perlite to see if this helps. But ideally I'd prefer them to be drinking more. I could possibly add a heater and/or a dehumidifier to try get them to drink more but then I may as well switch back to HPS as the power consumption will be nearly the same.

As far as I can tell I think adding some IR light to the mix might be the better option. Am I correct?
Also would this help the plants stretch a bit more as they are stacking way to tight with the COBs?
If this is a viable option, how much IR should I run per square meter?

Any other input or ideas is more than welcome.

Thank you.
 
Faultyboy

Faultyboy

Active Member
CobKits said:
raise temps and lower humidity

veg room should be 85 degrees with cobs
Click to expand...
Thanks for the info. I appreciate it.

I do have room to raise the temps and lower the humidity in my rooms stat's but it's going to require another heater and a dehumidifier be added to the room. I'm trying to avoid this as my power consumption will end up being the same as my old HPS setup. Then all the money I spent on this COB setup was a waste as I might as well switch back to the HPS without the need to buy another heater and dehumidifier. The whole goal of this exercise was to bring my power consumption down to get a second flowing room up and running.
 
ganjamystic

ganjamystic

Well-Known Member
CobKits said:
raise temps and lower humidity

veg room should be 85 degrees with cobs
Click to expand...
Faultyboy said:
Thanks for the info. I appreciate it.

I do have room to raise the temps and lower the humidity in my rooms stat's but it's going to require another heater and a dehumidifier be added to the room. I'm trying to avoid this as my power consumption will end up being the same as my old HPS setup. Then all the money I spent on this COB setup was a waste as I might as well switch back to the HPS without the need to buy another heater and dehumidifier. The whole goal of this exercise was to bring my power consumption down to get a second flowing room up and running.
Click to expand...
I think increasing the temp and lowering the humidity would probably increase evaporation, but not necessarily transpiration. in my understanding, maintaining good vpd is important for transpiration, and at 85 degrees, the ideal rh is actually around 75%... at 85 degrees, you wouldn't want the humidity to be any lower than ~65%

check vpd charts here
 
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Faultyboy

Faultyboy

Active Member
CobKits said:
i assume you already have great air circulation on the canopy, that will help transpiration
Click to expand...
Yes the room has been dialed in for a while. I did have to add an additional heater with the cobs. I'm just really trying to avoid adding another. I have fans on the canopy and decent amount of air coming in and out of the room. If I have to add another heater or dehumidifier as a last resort I could, but I really don't think it's going to make much of a difference in making the plants drink more. I was really hoping that adding some more light radiation could do the trick with minimal energy consumption added to the equation. As Ganjamystic said I want to increase transpiration not really evaporation.

I'm surprised I didn't come across this issue online before getting these COBS and that others haven't had to deal with such a change. Going from watering everyday to only once a week is a big difference and has thrown my whole room out of wack. Adding perlite to my coco might help but the plants still won't be drinking as much as I'd like. I'm definitely going to give the far red a try as recommended to help add more stretching.

I was just hoping to get more details on the use of IR and if it would help the plants drink more or if it would have any negative effects.
 
BobCajun

BobCajun

Well-Known Member
I suggest using the HPS with the COBs, since you have way too little wattage for 7 sq meters anyway. What are the Veros putting out, about 40w each? So 26 would be about 1000w, about 140w /sq m, about 14w /sq ft. I'm assuming you did mean 7 sq m and not 0.7. Add about 300-400w /sq m of HPS and you should be good, so like 2000-4000w of HPS for the 7 sq meters. The 26 Veros alone would be good for about 2 sq meters. Maybe have part of the space LED and the rest HPS, like the other 5 sq m.
 
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Faultyboy

Faultyboy

Active Member
BobCajun said:
I suggest using the HPS with the COBs, since you have way too little wattage for 7 sq meters anyway. What are the Veros putting out, about 40w each? So 26 would be about 1000w, about 140w /sq m, about 14w /sq ft. I'm assuming you did mean 7 sq m and not 0.7. Add about 300-400w /sq m of HPS and you should be good, so like 2000-4000w of HPS for the 7 sq meters. The 26 Veros alone would be good for about 2 sq meters. Maybe have part of the space LED and the rest HPS, like the other 5 sq m.
Click to expand...
I did think about that as well and that might be an option. I double checked my measurements and the grow space comes to 6.4 meters squared. When I did the initial calculations It came to around 600 to 700 ppfd per meter square if I can recall correctly. This is not for flowering at all, just a veg room which is why I chose to use 1050mA drivers instead of 1400mA. I do have more COBs which I can put up but I feel there is ample light for vegetation needs and this won't increase transpiration by much.

Here are a few picture of the setup. https://drive.google.com/open?id=0BzvCTWbIyqnPZzliSHR6cXpiUHc
 
Faultyboy

Faultyboy

Active Member
I'm really looking for more input on adding the IR spectrum as I think this will be the best route to get leaf temperatures and transpiration increased.

If I was to add some IR and far red star pucks from Rapid to my existing lights, how many would be needed to get a desirable effect?
 
Rahz

Rahz

Well-Known Member
Faultyboy said:
Hello Everyone,

I've just recently switch my veg room over to COB LEDs from HPS. (24xVero29@1050mA over +-7sqm)

My plants are in 100% coco. While using HPS I could get away with feeding my plants daily once they had established a good root system.

Now with the new COB setup I can only feed them once maybe twice a week at most as they just aren't transpiring as much as they used to. Some plants are still showing signs of overwatering even on this schedule and they all look like they need more feeds to get their nutrient requirements.

I have just started testing a batch of plants in 50/50 coco and perlite to see if this helps. But ideally I'd prefer them to be drinking more. I could possibly add a heater and/or a dehumidifier to try get them to drink more but then I may as well switch back to HPS as the power consumption will be nearly the same.

As far as I can tell I think adding some IR light to the mix might be the better option. Am I correct?
Also would this help the plants stretch a bit more as they are stacking way to tight with the COBs?
If this is a viable option, how much IR should I run per square meter?

Any other input or ideas is more than welcome.

Thank you.
Click to expand...
Have you tried increasing the nutrient ratio and watering less often?

Also, how close to the plants are you keeping the lights?

Increasing airflow (ideally using DC fans) would increase transpiration without a lot of electrical use.

Seems like you should be able to make it work without using more energy.
 
ttystikk

ttystikk

Well-Known Member
CobKits said:
raise temps and lower humidity

veg room should be 85 degrees with cobs
Click to expand...
THIS.

Compared to HID lighting, LED emits much less infrared and thus plants need higher temperatures to properly transpire.

Faultyboy said:
Thanks for the info. I appreciate it.

I do have room to raise the temps and lower the humidity in my rooms stat's but it's going to require another heater and a dehumidifier be added to the room. I'm trying to avoid this as my power consumption will end up being the same as my old HPS setup. Then all the money I spent on this COB setup was a waste as I might as well switch back to the HPS without the need to buy another heater and dehumidifier. The whole goal of this exercise was to bring my power consumption down to get a second flowing room up and running.
Click to expand...
Better insulation of your grow space will preserve your power savings. You had to shed excess moisture before you switched; how was that accomplished?

Raising temperatures will naturally reduce RH. Give it a try, keep us updated.

Different lights with different characteristics need a different approach. When you get it right, you'll like the results. I sure did!
 
Gquebed

Gquebed

Well-Known Member
ttystikk said:
THIS.

Compared to HID lighting, LED emits much less infrared and thus plants need higher temperatures to properly transpire.



Better insulation of your grow space will preserve your power savings. You had to shed excess moisture before you switched; how was that accomplished?

Raising temperatures will naturally reduce RH. Give it a try, keep us updated.

Different lights with different characteristics need a different approach. When you get it right, you'll like the results. I sure did!
Click to expand...
I'm having a bit of the same problem. I'm around 79-81f and 55% in veg with 3 week old seedlings. Cobs are about 30" above canopy.

So 85ish? Maybe bring the lights down some?

What is ideal for flowering?
 
ganjamystic

ganjamystic

Well-Known Member
ganjamystic said:
you want to increase leaf surface temp, but not necessarily room temp. I like around 75 F and 60% rh for flowering
Click to expand...
ttystikk said:
This won't work for LED, due to a dramatic reduction in infrared emissions.
Click to expand...
I'm just speaking from experience. I've been growing with leds for years, and have always done well keeping the flowering temps in the 75-78 range and humidity around 60%.. but I have been using blurples all these years, so they prob have some IR spectrum that I will lose when I ditch them.. something I should probably take into consideration when building new white based lights to replace them. the qb lights I just built were my first DIY project and they're the first all white leds in my garden.. I definitely will want to find a way to keep the temps in that range while still maintaining good vpd/transpiration because I feel like the lower temps seem to result in better flavor/aroma... so that will prob mean adding some reds to supplement the white or getting some boards or strips with red/far red mixed in with the white diodes
 
Rahz

Rahz

Well-Known Member
Most blurples use 630nm LEDs. Some use 660nm LEDs. Either way they aren't going to emit any IR unless they have IR emitters built into them. Even 80 CRI should have more IR than blurple.

I've also done well with low-mid 70s for veg and flowering. Granted I was growing in hydro back then. I don't know how much they transpired during veg but once they started to get some bulk I was topping off the rez prior to going into flower. 450 PPFD and 4 week veg to fill a 32x32 spot in flower. I always waited too long and could have easily used a 3 week veg.

I'm sure growing in pots is a different ballgame.
 
ttystikk

ttystikk

Well-Known Member
Gquebed said:
I'm having a bit of the same problem. I'm around 79-81f and 55% in veg with 3 week old seedlings. Cobs are about 30" above canopy.

So 85ish? Maybe bring the lights down some?

What is ideal for flowering?
Click to expand...
Same. Make sure you have good air circulation around and through the plants.
 
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