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What precise temperature is ideal for Veg and Flower

beethoven

Member
Hi all,

I've been growing a while now in a relatively cool grow space, around 72 lights on and 68 lights off...

Reading many forums and grow books, they seem to give a "range" from around 65 to 85 degrees.. That's quite a large range 20 degrees. Can someone narrow this down for me?

Thanks !
 

Creeperpark

Well-known member
Mentor
Veteran
Hi all,

I've been growing a while now in a relatively cool grow space, around 72 lights on and 68 lights off...

Reading many forums and grow books, they seem to give a "range" from around 65 to 85 degrees.. That's quite a large range 20 degrees. Can someone narrow this down for me?

Thanks !
I like staying in the low 80s in veg and upper 70s in flowering.
 

Douglas.Curtis

Autistic Diplomat in Training
What is your goal?

Massive yield is done with hot and wet conditions, so you'll want to listen to the RH advice for 80F. *Lots* of decent flowers.

Massive quality happens at 65F and super low RH. Fewer flowers, yet super frosty and amazingly resinated.

No matter what flowering conditions you use, vegging in warmer and wetter temps will give you larger plants for flowering purposes.

Edit: No... unfortunately you can not have both. At least not with today's technology and understanding. ;) A happy medium is definitely doable.
 
Last edited:

foomar

Luddite
ICMag Donor
Veteran
How are you measuring temp and RH ?

The cheaper sensors all seem to use the same hopelessly innacurate chip , caused me some confusion with the actual humidity.
cheapcrap.JPG
 

aCBD

Well-known member
I got one Ventilution hygro-thermometer with min/max from the growshop with a 2m sensor cable which is on canopy level and the main unit on ground level. Working great for over 5 years already.
Recently got a set of ThermoPro TP50-3
from Amazon which are hygro-thermometer with min/max but without a cable. They're hanging in the new tent on ground level, height of pots and canopy level.
Was sceptical but double checked them with the Ventilution and there was little to no difference so for the price they're doing the job.
Probably was high while ordering because SwitchBot costs almost the same and works with Bluetooth and logs a lot for days, shows VPD etc.
If you want pictures i try to get some when the lights are back on.
 

Hiddenjems

Well-known member
LED needs to be be warmer so I've read.

HPS or other HiD lamps I can speak on and keep temps around 72-75 lights on and 62-65 lights off.

RH no higher than 50 and around 35 in flower.
I run hid’s at 85* because I keep my co2 around 1400ppm. The humidity follows a vpd chart with temp until the last 2 weeks. Then it’s drier than optimal vpd for growth.


Co2 costs me around $40 a month. It’s the cheapest input with the highest roi.
 

Lester Beans

Frequent Flyer
Veteran
Even with CO2 I keep my temps with HID in the mid 70's. 80's for flower is too high to produce first class herb in my experience.
 

Phytoplankton

Active member
Some of the temp/RH requirements are also strain dependent, some sativas like warmer more humid conditions, while many indica's like it drier, kind of depends on where the strain originated.
 

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