Amateur psychrometry! Willis Carrier probably hashed out the math for this 100 years ago in Rational Psychrometric Formulae.
It’s always reassuring to see others with similar obsessions. I log data and record timelapses I don’t even bother to look at, but the data collection runs 24/7.
My cheapo ones vary only 1%. It’s good piece of mind. Unless they’re all equally off and then you’re screwed 
I also have two fans. One blasts below the canopy and the other blasts above canopy. They are very powerful fans.
Maybe a better mixing of the air would level it out for you🤷♂️
As I think about it, in that room I probably should leave be. No plants, just cut ones drying. At 5ft the humidity IS good for drying at 55-58%. If I really get the air mixing, an avg of 77% and 57% is 67% which would be no bueno…
I am still gonna toss hygrometers all over that room and the grow room next door to it to get a visual. Curious if the layering is still present since the grow room has 5 oscillating fans, doubtful but we’ll see later on today!
Hmm.
I’ve never used a sensor to check for layered humidity in the drying room. Maybe I should.
A good volume of fresh cut plants will throw off a lot of humidity. As they dry the humidity should drop a bit.
But it depends on a lot of things. Time of year, outdoor humidity, stage of drying.
If my convenient drying space were 70ish I’d probably be looking for a different space.
I’m lucky. I’m drying right now and it’s been raining all week and my humidity inside has been perfect at 60%. I don’t always get that lucky.
All the best.
Aside from the attic, its probably my best option (and my attic is an oven, not really liking the idea). Main floor of the house no way, GF already complains of the skunky smell, and we aren’t big A/C users, with our windows always open and fans on, humidity on the main floor is easily 70’s or higher all the time
Air by me has been very humid most of the summer. Wet weather has kept humidity pretty high. Back in June when my tents were just getting started my in tent humidifiers were actually pumping out humidity because it was so low. I haven’t filled them since early July (in June I filled em every other day)
Volume of plants I would consider low for drying, its 2 smallish autos really. When I cut and trim the 8 other autos then its a volume to watch I think. But there’s literally a dozen branches of larfy bud drying right now… and its 58% RH at the height they are at 
I do know that the soil buffers a lot of moisture, and there’s probably 200 gallons of soil down there at least, all at floor level…
Not so worried about correcting / evening out the humidity in that room just yet, we’ll see after chop and trim of the inside autos though. For now its just an interesting observation, and something to learn about
Soil reads -3% because I took the probe out while watering and its still on top of the tent.
But look at the bar graph for temp and humidity.
Daytime temps avg 82-84, night is 75-76
Daytime RH is avg 59-60% and night it climbs to 67-68%
Really neat to see the graph and correlation. I could also see a rise in co2 when I was in the room (before I got the co2 bag), but now with the bag I see the co2 drops with lights off, and rises again with lights on… In all 4 graphs in the pic thats the prior 24 hours, so overlay them on each other in your mind to see the correlations. Neat stuff for sure, maybe a bit overkill for some, but I had fun assembling the system so far. Kinda like an erector set, but with cheap electronics
ps. I scattered all sorts of hygrometers at various levels in both rooms this morning. When I go down there later I am curious to see what each reads
Slick looking dashboard. Did you whip up that design?
Remember, this is relative humidity. As the temperature drops, it can hold less water and the relative humidity raises.
Yup! Its basically Home Assistant, mostly stock stuff… Raspberry pi, some ESP32 modules with sensors, and TP link switches 
Cameras are even ESP32 cams… Very affordable for the geek in me to assemble
This is awesome! Do you have anything running on ESP32 relays? What actions do you automate if any? I’ve been looking around for different grow automation systems but leaning towards Home Assistant since it seems more open-ended and much easier to use.
In the grow room not yet, but I also have a model RR that I block sections of track using them. I do have some ideas for operating a 120v valve that I recycled from my washer though, and the relays will work with 120v, just haven’t jumped into that yet. I setup an 8 channel relay for shits and giggles, just looking for ways to integrate it… I probably could have made an outlet box and controlled it with relays instead of buying the switches, but I wanted the simplicity of the Kasa / TP link enabled switches really…
Temp and / or humidity trigger the exhaust fans, humidifiers and dehumidifier. You can see in my screenshot above that I have a target and tolerances for humidity and temp. Working on a few YT tutorials I got the basics together, then found a few other snippets of code I liked. The colored graphs are an add-on (free), because the stock was boring looking. The rest of what you see is vanilla home advisor, nothing special.
I’m not a coder, so I gotta find code / reverse engineer for my needs, but if you know basic coding, it’ll probably be very easy. Perl, C and Java / JSON would be super helpful, but its not an absolute, as I know NONE of them…
Seeing as I can measure soil moisture, my next integration will likely use that washing machine valve, triggered, and feeding a drip system. Since I’ll have to add nutes separately, it will have to be dialed in to provide the absolute minimum, and thats what I am researching now… I know the relay will trigger the valve perfectly… It would also work with 24v valves / associated power supply should I chose to ditch the 120v ashig machine valve and go with sprinkler / low voltage stuff…
Definitely a powerful setup, and so far to me only limited by my imagination…
ok, so here’s the numbers…
Room adjacent to grow:
On floor 80%
2ft off floor 71%
5ft off floor 56%
Grow room
On floor 67%
2ft off floor 65%
5ft off floor 63%
Do note: the grow room has 5 oscillating fans, so its blending more. I only have the one dual fan in the drying room.
Thanks for the detailed breakdown. I am also a decent code copy-paster so this sounds like it could work for me.
If you have any questions along the way I’ll be happy to answer or point you to the solutions I used…
Really easy to integrate!
shit, you should start selling that package, i know id buy one
Nice setup! I am running home assistant as well and its the best thing since sliced bread. I use Ruuvi tags for temp/humidity reading. They use the bosch BME280 that is popular and are in a waterproof plastic puck which is nice for humid grow tent environments like mine. There is a Ruvvi integration in HA and the Ruvvi tags don’t require bluetooth pairing which is nice. As long as you have an esp32 board already in play you just have to hard code the MAC addresses for the tags into your Yaml file and upload it to the esp32 board. So far they have been really good and the readings seem to be consistent.
I have a bunch of smart electric switches that I have my lights plugged into and I control the schedule using Node-Red automations. Same thing with a dehumidifier with triggers set based of the Ruuvi tag readings.
The shit is cool and the sky is the limit if you know some coding. I bet I am all in for less then $400 and I have a system that would have cost over $2000 off the shelf if I bought something like TrolMaster or a true PLC system.
What soil moisture sensor are you using? Automated irrigation is the next automation I want to add to HA.
Also if you are looking at power relays check out the Shelly relays. They are ESP8266 based and are made to be flashed with Tasmoda by having easy access to the pinouts of the board. They also have an integration into HA so alot of people don’t even bother with flashing Tasmoda since the built in firmware is pretty good. They are out of an Eastern European country so not Chinese made hardware like Sonoff. I want to move my lighting off the TP Link smart switches and tie the wifi enabled Shelly relay directly into the power line. I feel like this will be a cleaner connection for power.
I honestly thought about it. But it does require a fair amount of configuration at the end user. Then I remembered my time as a Dell tech, and how some people shouldn’t even own a computer, and had second thoughts… The problem is that the remote sensors, aka the ESP32 chips, need to be programmed with network access info, the switches need to be linked from a different app, change a switch name slightly and its broken. If there was a truly Plug N Play way I could, I’d consider it. To someone slightly tech savvy, a cut-n-paste programmer, or someone who’s built their own PC, it would be pretty easy to setup. To others, it would be all greek, and lots of people want it to “just work”.
I bought raw BME280 sensors for the ESP32. The Ruvvi are a nice option though. The BME280 sensors are only a few dollars for a multipack. The co2 sensor cost closer to $20.
I like the idea of one upload to an ESP32 board with the Ruvvi tags, that would solve some issues for a new user to setup, certainly make it a little easier.
All my automations / triggers for the lights and humidifier (and shortly adding the dehumidifier) are in Node-Red as well. Powerful piece of software there once you play a little and realize the flow of it all.
All in here, with all the sensors and switches, including the Pi4 / 4gb that runs it, maybe $150?? ESP32 modules are cheap, most sensors are cheap, the TP Link / Kasa switches weren’t even that expensive. The Pi was probably the most expensive thing… Sure, I can 3D print housings for my ESP32 stuff, thats a big advantage for sure… But even using Ruvvi tags its not cost prohibitive
Resistive sensors have lots of issues, notably deterioration / degradation of the actual sensor itself. Not worth it.
Nice Dashboard. I love how the charts put into perspective temp / humidity swings, how they interact with each other, with the co2 (for me). My cams are ESP32 cams, but I have Wyze Cam V2.0’s I will be swapping to (the 3.0’s dont have firmware that can be flashed for HA, the V2.0 does). I have a few 120/250v relays for raspberry pi / esp32 here that are simple as well… Assign the pinouts, connect to an ESP32, and I have an 8 channel relay capable of handling 120v no issues…
The sky and your imagination really are the limit here… The tools are there, just gotta make the best use of them, thinking outside the box at times…
make a walk through or a video.
