The Polar Vortex - Baby, It's Cold Outside

Man! I did not think that the Lions were going pull that one out!!

Was close fer sure !!!

2 running here going through about 7-8 gallons a day maintaining ~63% rh in a basement 4x8 tent
Luckily only filling them once a day as they are 5 gallon buckets
Keeping the whole house about 45%
It can be a challenge opposite of summer and getting rid of humidity but that’s around the corner

Yikes. I’m running 2 console humidifiers in the house that are consuming over 6 gal a day and I can still only keep my RH at 16%.


8 gals a day and house is at 28%, need a bit of warm up to get moisture back, luck to all north dwellers to come out of our deep freeze for a few days, we know it will be here again soon.


Humidity is definitely on the rise, outdoor temps will be 30’s to 40’s. Tents have moderated. Girls are looking happy. I fed the autos GH Maxibloom for their last meal…I think :thinking:

Here in MN this winter has been a really challenging. For the most part, it’s been unseasonably warm which cuts consumption for those of us growing in basements (good). But when that cold snap hit, it really impacted our whole collectives’ grows. Yes, we all understood RH but the fact is that it really doesn’t tell us anything about a plant’s ability to respirate and carry out it’s business. That’s kPa and it’s the dance between temperature and humidity. Just because you are technically in “the range” with either temp or RH does not mean you’re making the plant happy. The Moderator is correct in saying you don’t need to drive yourself crazy chasing kPa, but it makes a big difference. out. Once we got that dialed in, everybody’s plants were off to the races. I think of it this way: kPa is about air pressure/weight. The plant is porous and contains water. Water will always try to equalize. So if that weight/pressure in the tent is higher than the tent (low kPa) the outside air is trying to push its way into the plant to equalize. That makes it hard for the plant to pull up nutrients from roots to canopy. If the weight/pressure in the tent is lower than that in the plant itself (high kPa), then the plant is going to exhale moisture to try to equalize. Photosynthesis is compromised and the plant tries to protect itself by producing light buds. We spend a lot of time talking about dirt, water and light. In a winter like this, getting a handle on kPa was a game changer. It’s not as complicated as it might seem. If you can establish a consistent ambient temperature in your room all you need to manipulate is the humidifier in the tent. If it doesn’t have a fine tune feature you can adjust the amount of water vapor in the tent by tweaking your exhaust fan speed. At night the temp in your tent will drop. So you don’t want to add as much water vapor. But just like dialing in during the daytime, it won’t take you long to know where the humidifier and fan should be set at night. It took all of us well under a week to wrap our minds around how humidity does not matter: kPa does. One key is that however you’re measuring your RH and temp numbers you need to make sure they are accurate. In general, you get what you pay for and calibrating your instruments is always a good idea. Quite literally a couple degrees or RH %pts will throw off the chart provided by the Moderator significantly. I’m not shilling for any particular product line here but my sense is that AC Infinity is kind of out front in the automated, kPa focused world for home growing. Our bunch has installed those controllers in all 5 of our tents and everybody is stoked. Doing that kPa dance is counter-intuitive but once you wrap your mind around it, you will identify so many prior issues that were nothing more than not letting the plant breathe easily.

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