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Ideal temps when lights are off Veg & Flower

Headchef710

Member
Was hoping yous guys could tell me the acceptable range in temperature when the lights are off during both the veg & flower stage..

Thanks troops !
 

fanleaf

Well-Known Member
IMO it kinda depends on what temps you run during lights on. Some growers run 75-78 at the canopy during lights on like I do. In that case as long as my room dont get any colder than 58 degrees during the dark period I see zero I'll effect. It's more important IMO to keep the temp swing between night and day at no more than 20 degrees. Some growers lights on canopy temps are kept at 85 degrees and in that case I would recommend night temps no cooler than 65 or so.

Staying inside those parameters has served me well.
If I'm not mistaking there can be cellular damage (of some kind), when temps hit the low 50's. To what extent, I don't know because I never let it get that cold.
 

The Celt

Well-Known Member
Most growers tend to keep temperature swings within 10 F if they are able to control them.

About the only time most will allow nighttime temperatures to dip more than 10 F is in late flower if you are trying to promote a colour change.

RC
 

AdaminCO

Well-Known Member
This is what I go by.
Night time I try to have 10F cooler.
In Flower, you want your RH to be lower.
In VEG I run:
Day 75-80F @65-70RH
Night 70-75F @55-60RH
In BLOOM I drop RH to 40-45%.
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AdaminCO

Well-Known Member

The Celt

Well-Known Member
In all honesty AdaminCO, I have learned from my plants that if I find it slightly warm and too bright, my plants are loving it.

My RH rarely gets over 50% in in the basement where I grow and I keep my temps under 80F during veg and not over 85F in flower and have great luck. Now having looked at that chart, RH (which I knew) is low for veg at those temps but great during flower.

The only thing I found about having low RH during veg is that they require more water but still grow well.

RC
 

Headchef710

Member
Ok thanks for the feed back its apprecited..

Today is the Lowest my temp has been is 13c thats just as the lights were switching back on from its 6 hour dark period should i be worried at that?

I do live in a very cold country to be fair
 

The Celt

Well-Known Member
OK, your in Celsius, if you have a way to keep in between 16 and 22 degrees, you would be right on the mark for good growing temps.

RC
 

AdaminCO

Well-Known Member
In all honesty AdaminCO, I have learned from my plants that if I find it slightly warm and too bright, my plants are loving it.

My RH rarely gets over 50% in in the basement where I grow and I keep my temps under 80F during veg and not over 85F in flower and have great luck. Now having looked at that chart, RH (which I knew) is low for veg at those temps but great during flower.

The only thing I found about having low RH during veg is that they require more water but still grow well.

RC
Yeah I’m growin in my basement too... it’s hard to keep the RH up in winter time for sure. Here’s where mine are right now. (Out) Loving life.
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The Celt

Well-Known Member
As for dropping to 13, no worries, healthy plants won’t mind, it is just not optimal.

Healthy, mature plants can even withstand a few frosts in the spring so long as it is not a hard frost.

RC
 

The Celt

Well-Known Member
About the same in my tent AdaminCO. I checked on the 20 young Blue Dream I moved into the big tent. Temps running 80F and RH @ 42%. Not optimal for young plants but they are growing great.

RC
 

AdaminCO

Well-Known Member
About the same in my tent AdaminCO. I checked on the 20 young Blue Dream I moved into the big tent. Temps running 80F and RH @ 42%. Not optimal for young plants but they are growing great.

RC
Same. I have another humidifier but they seem fine.
I flipped the bloom switch on with the veg, so I had kick the exhaust fan up a bit to suck the hot air out, and pull the cooler outside. That’s causes my RH to drop about 10%.
 

AdaminCO

Well-Known Member
Cant thank you guys enough, thanks for being so helpful man,

Happy growing:420:
Anytime...
Check out all the links in my signature. Everything I’ve found helpful I’ve linked.
 

The Celt

Well-Known Member
Yes @AdaminCO, I had to put a heater in the tent so night temps would stay around 70, it’s run by a thermostat at about 10” off the floor. These girls are young and got moved from a space that stays in the 70/80 range and I avoid stressing young plants. That meant that I had to run the 6” fan at its lowest setting to keep the lights on temps below 80.
 

AdaminCO

Well-Known Member
Yes @AdaminCO, I had to put a heater in the tent so night temps would stay around 70, it’s run by a thermostat at about 10” off the floor. These girls are young and got moved from a space that stays in the 70/80 range and I avoid stressing young plants. That meant that I had to run the 6” fan at its lowest setting to keep the lights on temps below 80.
So I did that with my last two grows, and always had trouble positioning the heater so that it wouldn’t hit the plants.
I now set it outside my tent about 3’ away from one of the vents so that my exhaust fan pulls the hot air into the tent. Problem solved, and it actually regulates it better.
The two I have sitting outside the tent have heat now too.
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