It seems to me that the most relevant place to monitor temperature and humidity in a tent is the canopy. That location is problematic, though, because the probe will absorb radiant heat from the lighting, causing a high reading.
A simple solution occurs to me: Nest a few (maybe 3?) styrofoam cups together and make a hole in the center of their bottoms to pass the probe’s cable through. Add a few holes along the side, near the bottom of the cups, so warm air can pass through. Hang the probe inside the cups, with the cups upside down, so they become an insulated lampshade with low light transmission.
I expect I’m hardly the first to think of adding a lampshade to the probe. Does anyone have experience with this idea?
Me too! I thought of it while reading Robert Bergman’s guide titled “Best temperature for growing marijuana plants.” He advises measuring at different locations but always in the shade.
I’ll report back after experimenting with this idea.
Used to do it with my AC Infinity probe but I started wondering was it creating it’s own mini environment under the shaded area so I removed it. The way I look at it is the leaf doesn’t get shade so the probe shouldn’t either so that way they’re in the same environment and the readings should relate to what the plant is feeling. @Low you’re a great grower and awesome at helping people so if my thinking is wrong please correct me.
Thank you @DoneDeal I think technically they are supposed to be shaded just so they don’t pick up heat from the light. I only noticed a difference in a few points. I think it provides a more realistic reading. in my case it really didn’t make a huge difference. Most of my runs have been done without a cover, just recently started playing with it. Not a deal breaker either way.
Kind of like increasing heat in a room can decrease humidity. Same thing happens if the probe or meter gets warm from light instead of the environment. Inaccurate representation of numbers. Acts as a heat sink, if that makes sense.
@TheAbu95
Just tried an hood for his meter and saw a significant increase in humidity and drop in temp.
I think that plastic case retains heat. I figured the humidity would go down a little being in the middle with that fan up top pushing air around but it seams to be holding about 10% higher than where i previously had it.
This was a previous run, i just poked a hole through a piece of cardboard and then put a piece of tape from the cardboard to the tent. Ive found that my probe reads about 10° and 10% higher than what the govee does. Ive grown pretty fond of my govees lol
Did you calibrate the probe and Govee after letting them sit side-by-side for awhile, so they give the same readings when exposed to identical temperature and humidity?
I don’t see how the cardboard shade in your photo would trap heat or moisture and produce a 10° increase in its temperature measurements and 10% increase in humidity. Seems to me that your shade should reduce the temperature reading and have no effect on the humidity measurement.
Another possibility is those differences are correct and result from measuring in two different locations. @Low has his instruments side-by-side, which is a better arrangement for testing this idea.
So far only temp has gone up on the uncovered one by 1°
Location location location. I keep 4 meters in the area 1 above lights, 2 at flower canopy level under lights, and mid span up a wall outside of the lighting footprint. Also have lung room monitored.
I don’t fully trust any one of them but it gives me an idea of the space.
The 10% 10° difference its between what the probe says and what the govee says, not the difference after adding cardboard. The cardboard didn’t effect that. That pic was from a long time ago, I unplugged the probe on my last grow because i didn’t trust it. I tested it against 3 other types of hygrometers. The govee is the only hygrometer i currently use. I have 4 of them running.
Aha. I let my probe and digital controller (which has its own temperature and humidity sensors inside) sit in the same spot with a bulb thermometer for an hour or so and then adjusted the temperature readings to match the bulb thermometer.
I’ve noticed that exhaling near the sensors increases their temperature and humidity readings. It’s nice to see them respond, and so quickly, but it means I need to hold my breath or exhale in a different direction during calibration!
@Low : Hard to say whether those small differences are due to the hood. Can you move the hood to the other Govee and see if it then gives a cooler reading? (I can’t think of a reason your hood should affect the humidity reading.)
Interesting . Ive never heard of that, i bought a few different kinds and then have that smart controller. Im not sure which ones are the most accurate i just went with the most consistent and rolled with it .
… Y’all see what I mean!!!
Me too
. Ive never heard of that, i bought a few different kinds and then have that smart controller. Im not sure which ones are the most accurate i just went with the most consistent and rolled with it 
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