Optimal temperature, humidity and EC

Lavindo

Member
Hello. Im on my first grow, and I have some questions I hope some of you know the answers to
I'm growing hydroponic btw.
What is the optimal temperature during night and day in flowering? And the same with humidity and EC thanks!!
 

King Avitas

Well-Known Member
Hello. Im on my first grow, and I have some questions I hope some of you know the answers to
I'm growing hydroponic btw.
What is the optimal temperature during night and day in flowering? And the same with humidity and EC thanks!!

Well that depends. There are scenarios that change those parameters form room to room and strain to strain.

A general rule of thumb for a basic set up is:

55% to 65% humidity lights on from seedling to mid Flower cycle, mid to late flower 40% to 50% humidity. Then for lights off, try to stay under 50% humidity with good air circulation from fans and that should keep most grows safe.

As for temps try to keep them under 85⁰f but over 75⁰f from seedlings to mid flowering cycle. Then you want to try to keep your mid to late flowering temps at about 70⁰f to 72⁰f to preserve terpenes. During lights off, try to stay about 10⁰f cooler than your lights on temp but don't go lower than 65⁰f.

Now you can throw everything I said out the window if you are trying to maintain VPD (vapor pressure deficit) or are using CO². But that's a story for another time.
 

LeastExpectedGrower

Well-Known Member
For temperature:
-80f for mats for germination
-75-85f for the duration for me is the goal. My lights-on temps are 82-85, Lights-out 74-79 generally.

For Humidity:
-Germination through the first 2 weeks of veg ~70% RH give or take.
-At week 3 I start pulling back humidity into the 60-65% RH Range.
-Once I hit mid flower I've been aiming at 50-55%
-After mid flower I taper down into the mid 40's.

During most of the grow I'm trying to keep the VPD somewhere in the range of .8-1.3, of course as your temps fluctuate between 75-85 but your humidity remains locked in within a few degrees, VPD also drifts in range.

I prioritize my temperature over my humidity. I've measured my leaf surface temperatures to be -2f or -2.5f from ambient when in the 80's in my tent, with lights on so having the heat up in the 84-86 range isn't a problem.
 
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