Lack of CO2

[organicness]

Hey there,

Can a lack of CO2 cause new growth to yellow and growth to basically stop? I've got a great outdoor patch going using the same nutrients, same EC, same pH (everything getting pulled from the same rez) as the indoor stuff (in my basement), and the stuff in the basement is getting yellow new growth (no green spline or anything, just all yellow) and not growing taller anymore. Things were growing fine in another tent that's closer to the stairs and always open, but when I put them into this particular room in the back of the basement everything seems to go awry.

They're surrounding 1000w vertical in coco/hydroton getting fed 640 ppm (.5 scale, 1.3EC). Things are vented by a 400cfm fan pulling through an air cooled hood with one end of it open (that's in a bigger tent inside this room, the plants in there experience the same problem). With my outdoor stuff going so great, stuff in another area of the basement doing just fine, the only thing I can think of is that maybe there's a lack of CO2. I just don't have a way to measure the CO2 in the room, and damned if I had enough money to buy a CO2 setup right now.... :(

Could this be the issue? In the winter the room produced really well, but this summer, things aren't that great. The temps range from 72 at lights out to 83 at lights on.

Thanks for any thoughts.

 

[sox]

maybe humidity? I really dont know...if you think its lack of C02 you can grab those "greenpads" or something like it...i was talkin to a guy about em and he said he uses 4 of those in a 4x8 tent...they were not the greenpad, but something like it.

 

[organicness]

HUmidity is around 70% at lights out and 55% lights on.

 

[sox]

hmmm, who knows...im not an expert on RH.....give the c02 pads a shot, cant hurt.

 

[Bannacis]

83 degrees is getting on the high side, heat plus high intense light, 1000 watters and a good feeding will raise your plants metabolism, and it will use much co2 surrounding your plants.
if the co2 gets too low the plants will stop, and you can also get nute lock, so your new growth will suffer.
You didn't state how many plants you have under the tight, plus the air your pulling in your tent...is it from outside?
But deff the 1000 w light will require co2 if your not bringing in enough fresh air... need temps in mid 70's

 

[organicness]

Thanks. I'm going to give some Co2 a try and see what happens. I was reading up a little and I've got around 4k lumens per square foot (6x6 space with 1000w donut vert), but I don't really know if I'm doing that calculation right in a vertical setup. The 1000w is hanging with about 20-24 inches of distance between the plants and the bulb. Probably some pretty intense light I would guess for a minimal CO2 content in the air.

 

[joehank]

I'm guessing you have forced hot air for heat? That would explain why your winter grows did better, more residual CO2 in the basement. Also more air circulation. I say if you have any windows you can open, with a fan pulling fresh air in, you'll do better.

 

[organicness]

No, the basement doesn't get any heat at all. We heat with a woodstove. I'm headed to bite the bullet and get some CO2. cross your fingers

 

[Bannacis]

yeah, i bet thats the ticket, lack of co2, but ya need to get your daytime temps to mid 70's and your dark cycle to mid 60's at least both temps 10 degrees cooler.
you also need fresh air brought in, even with lights out. toes crossed...

 

[organicness]

Hmm, I wouldn't want CO2 and temps in the mid-70's, though. The plants wouldn't make use of all the newly available CO2 at that point. Plus, I don't have money to get an AC that isnt' going to suck all the new CO2 out of the room. I just have a window unit that I converted into a portable, and it takes inside air and pushes it outside. We'll see... about to head down to the room and check.

 

[cctt]

• If you're ventilating the room enough that it would waste enriched CO2 levels it sounds unlikely that lack of CO2 is the cause of your problem in the first place.
• If you have an AC doing both the venting and cooling that you'd no longer want with an enriched-CO2 setup, could you just turn it off?

 

[organicness]

I don't run the AC during lights on. Gets around 90 in there.

BUT.... after tons of research and talk with other growers in my area, I really don't think it's a CO2 issue anymore, but rather an issue with the Agromax tent in the room. I started to have issues with growth since I put the tent into the room back in April, but never once thought it was because of the tent. I've been scratching my head for months trying to suss out the problem, and today one of my friends said he had to take his tent back to HTG because it was off gassing and killing his plants. He posted pics, looked exactly the same as mine, and am now tearing the tent down. Here's hoping that's the issue. My friend said his plants have been doing great since he took the tent out of the equation.

The floor of the tent after I took the protector piece off... it's black underneath a real thin layer of plastic and REEKS of paint thinner.