always thought with Co2 that u needed higher temps and the right humidity to make it even worth running the Co2

thats not pertaining to cannabis IMO. even with co2 you dont want high temps.

temps over 80 degrees under the lights will cause hairy buds with less trichome development. on the other hand, it will produce bigger buds. so you will have big ass 70's bush buds that arent appealing and look and smoke like crap.

90 degrees is way to hot indoors. especially if your going for top quality. mid 70's under the lights is what your after. with or without co2. doesnt matter with cannabis.

Empire is right. 90 wont kill them. Once in awhile should & would be fine, But I would try and get your room down to the lower 80's at least. Co2 does allow you to run your room a little warmer than with out co2, but running the room constantly at 90 is a bit much.
I tend to run my room on the warm side during the beg. of flower then progressively get cooler towards the end. You don't want your root zone to cold.

90 with co2 is fine. The co2 will accelerate transpiration rates so compensate with more water and nutes and your good.

Don Ganja said:

90 with co2 is fine. The co2 will accelerate transpiration rates so compensate with more water and nutes and your good.

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I respectfully disagree. While 90 wn't kill them, it will cause them to spend too much effort protecting themselves from the effects of high heat and not enough on growing and creating the resin we're looking for.

The general consensus among experienced growers is that without CO2 you want the temps to be in the 75-79 range, with around 65% humidity. With CO2, you can bump that up to between 80 and 84 with around 70% humidity.

I know these humidity values sound high, but we're looking for a reasonable VPD, or vapor pressure differential so as to encourage plant growth without stress. If VPD is too high, that is, humidity is too low for the given temperature, then the plants will close their stomata to conserve water, effectively stopping their uptake of CO2. If VPD is too low, or too much humidity for the temperature range, then the plants won't be able to transipre enough water to draw nutrients up and grow effeciently, also slowing growth.

90 degrees is just too high, and that's still true even if you want to run your relative humidity values in the high 80s! only at the end of the bloom stage do you want your humidity levels to fall somewhat.

All valid points. Seems to confirm what I suspected.
I've started letting the Rh climb to 70% during the day, something I've learned recently here at the Farm.
Guess it's time to reinstall the AC unit. I was hoping to get away without it this winter.

On a side note, just started using the Sentinel CHHC4. This thing is bad ass. A lazy growers dream.
Thanks,
Fred

Fred Flintstoned said:

All valid points. Seems to confirm what I suspected.
I've started letting the Rh climb to 70% during the day, something I've learned recently here at the Farm.
Guess it's time to reinstall the AC unit. I was hoping to get away without it this winter.

On a side note, just started using the Sentinel CHHC4. This thing is bad ass. A lazy growers dream.
Thanks,
Fred

Click to expand...

I run one of those, too- a very good unit, and representative of most of the equipment these folks offer. I recently had the remote sensor fail on my CHHC-4. I talked to the techs at growgps and after trying a couple of things, they had me send it in. They fixed it, FREE, and sent it back in less than a week total turnaround. I even told them I wasn't the original buyer... That kind of customer service is worth its weight in gold.