So I’m currently growing in a typically dry climate. My grow tent is in a basement, 4’x3’ built from a camping tarp that has been repurposed. Currently in veg at 20/4 with three clones. Running on CFLs and keeping temperatures currently in the 70’s.
I’ve been playing this game with humidity and I can’t seem to figure out if I’m driving myself crazy or not trying to perfect it. Currently running a consistent exhaust and using an aquarium heater in a five gallon bucket. Some days I get a humidity of 55%, other times it is at 40%. I I’ve been able to keep it at ~42-45%. Am I driving myself crazy try to deal with the humidity and let it just do its thing? The plants aren’t having issues and I expect to be watering a bit more due to a dry climate. I used to live in extreme humidity so that was a different process to bring it down. Any thoughts from experienced growers on how to go forward?
I wouldn’t worry , as the plants grow humidity will rise anyway , the dryer climate will work in your favor in flower , I would rather live and grow in a dryer climate than a more humid one , plenty of other things for you to ponder over : )
Yes. That said, when VPD is near ideal I’ve seen 10x the growth rate in veg. It’s also asking for PM problems unless you can ensure dry lights-out periods.
Raising the basement humidity sounds sketchy to me but maybe that’s where it’s “leaking” to? the cold walls & floor? Or does the tent exhaust to outdoors?
Using a hand sprayer to mist tent walls could be all you need.
If one keeps exceptionally good airflow with new air replacing the old, humidity becomes a bit less of a concern. I’d never recommend having high humidity, but when you’re forced with it, evasive measures help.
Lollipop, ensure at all times that the grow floor is clean, ensure adequate airflow particularly underneath flowering branches, and ensure that no under-or-over fertilization occurs.
i have a small dehumidifier and humidifier over the last week i used both, i try keep humidity around 45 during flower period over 50 when veging, has been a very wet summer in my area
My tents stay in the 40’s and 50’s with humidity, my tents are in the basement too. I was looking for ways to increase the humidity. You can add some saucers of water in there. Personally I just left mine alone. The plants do not seem to mind to much. They are growing 7 to 10 inches a week now that I brought them inside.
Seems to be a lot less problems when you have low humidity then high humidity.
I’ve been running my humidity much higher this run and I’ve seen much better growth than the past few times. During veg I keep the RH around 70% and now that they’ve been flowering I keep them at 60%.
Too low of humidity can cause over transpiration and lead to EC spikes and lockout issues in the medium (especially coco)
A lot of good points and kind of fuels my suspicion that humidity is a growers choice based on experience. For a first time grow in a new environment, I am going to try to keep it about 40% and see how it does. Vegging is far more forgiving but I’d like to know I can keep control of humidity. In the future I plan to invest in better equipment to respond to temperature and humidity. Until then we will see how it goes!
Thanks for the feedback everyone, I will try to remember to update once I am into flowering how humidity has gone!
Here is a VPD chart, it will give you an idea of where to be. In the green zone as close to 10 as possible is optimal, but as others have said you need good air circulation as well, as a correct VPD may cause PM or mould.
It is dry AF where I live and I don’t do anything about RH in my tent. Never have any issues related to it, but I run in soil with mild organic nutes so I literally don’t worry about anything. I do need to water every day, though.
As a side note: my outdoor plants are subjected to 100F summer temps with RH in the low 20s and they grow fine, so why would I pamper the same plants indoors?
I water moderately every day - I don’t flood them till they run through. (I don’t believe in the “flood them and then let them dry out” theory). This actually depends on container size. 1 gallon fabric pots - every day. 3 gallon fabric pots - every 2-ish days.
I’ll say it again, DRY AF and tons of air exchange through my tent.
I also live in the high desert, very dry here. I have noticed a benefit to having higher humidity (proper VPD) has much more effect in veg than flower. I use a cool mist humidifier on a humidistat.
I don’t know what we would do without forums like this. I agree with your rabbit hole analogy. Every single thing you research has eight million answers/opinions. Everyone on here seems to be legit and knows what they’re talking about!
Mine does the same thing man dont even worry about it. Now if I’m not running my exhaust with seedlings I can maintain 65% in my tent running a humidifier. But once I run my exhaust consistently I tend to range between 40-50% and sometimes a tad higher later in veg with more green in the tent.
That said, when VPD is near ideal I’ve seen 10x the growth rate in veg. 
It’s also asking for PM problems unless you can ensure dry lights-out periods.
Yeah–like leaving the door open, heat & moisture leave
