Question about Temp and RH

[snerval]

Hi,

I'm posting this here because I didn't get answer on my grow journal.

https://www.autoflower.org/threads/first-grow-ever.85096/page-1

My plants look healthy, but I would like to give them the optimal environment conditions if I can ^^

I can't find a surefire info about the ideal Temps and RH for light ON and light OFF.
At the start of my grow I knew I needed a lot of humidity, but now that the girls are flowering I try to low the RH down.
But I would like to know what in your opinion are the best values to keep an eye on.

Thank you !

 

[CannabisMingus]

I use this chart and have been relatively happy with it. I recommend an IR gun and use leaf surface temperature.
HTH, YMMV, IMHO, etc.

Edit: I say "relatively" because in my experience cannabis has a wider potential VPD range than indicated, but it's a good rule of thumb.

 

[snerval]

Thank you.
Do you measure leaf temp below the canopy ?

In fact I used a lot VPD charts - although not these ones and with no leaf temp knowledge - at the beginning of my grow, because it was very hot, and I'm thankful to these chart as they allowed me to inject humidity accordingly.

Today and more simply, I would like to know what is the recommended temp for light off/light on, min/max ?

 

[CannabisMingus]

Thank you.
Do you measure leaf temp below the canopy ?

In fact I used a lot VPD charts - although not these ones and with no leaf temp knowledge - at the beginning of my grow, because it was very hot, and I'm thankful to these chart as they allowed me to inject humidity accordingly.

Today and more simply, I would like to know what is the recommended temp for light off/light on, min/max ?

@AutoBobje thanks for the rep!

@snerval I measure at top of canopy

As to the min/max question - that depends on RH. Considering one without the other can be problematic. Very broadly speaking, I try to keep leaf temp at 79-80 F during veg and 75-77F during flower, with lights off approx. 6-8 degrees cooler. But that's just a target and it shifts depending on RH.

 

[beavens]

VPD for the win!! You can definitely operate above and below the ranges, but if you really want to dial it in then try to match your environment to the chart of the cycle you're currently in.

To make my life easier, I bought an InkBird temp/humidity controller that will automatically maintain a specified temp/rh (assuming devices with mechanical on/offs).

 

[CannabisMingus]

, I bought an InkBird temp/humidity controller

Inexpensive, reliable, and accurate enough for our purposes (although I usually check).

 

[beavens]

Inexpensive, reliable, and accurate enough for our purposes (although I usually check).

I *really* should do my DD and double check the numbers. I know that they won't be off by enough that will completely throw things off, but I've been lazy.

 

[CannabisMingus]

Thanks for the rep @beavens - I agree!

 

[CannabisMingus]

I *really* should do my DD and double check the numbers. I know that they won't be off by enough that will completely throw things off, but I've been lazy.

I hear you When I remember, I just check it against another 2-3 hygrometers. If it's +/- 2% or so I'm cool.

 

[snerval]

Thank you guys.
I've read somewhere (not on AFN, can't remember where) that RH should be kept pretty low during flowering stages to avoid mold issues.
That's why I'm concerned about that.
I'll stick with @CannabisMingus temp recommendation and I'll try to adapt RH following VPD charts.
I hope I will not screw things up, because so far I was lucky enough to maintain my plants healthy