Hey how you all doing , my girls are ready to go from nursery tent to grow room I’m just a little concerned about how low the temp gets when the lights go off the lowest I’ve seen it get is about 48 degrees not for the entire 6 hours the lights are off ,so this morning I turned off my fresh air intake fan and I turned the exhaust fan down to low , but anyways I guess what I’m trying to ask is 48 degrees fahrenheit going to be to cold the girls are in pre-flower at the moment
I think 48°F may to be too cold . . . rule of thumb is no lower than 60 with a max light/dark temp variance of 20°F.
That being said, and if memory serves, they do fine outdoors when temps go below 60.
I usually don’t go under 55 but since I changed my grow room around its a little cooler then my last grow, I’m going to leave them where thru are until I make sure I get the temps back where they should be I’m thinking with the fresh air intake fan off that may get it back up where I want it and if that don’t get it I’ll plug the exhaust fan into the timer so because it still pulling cold outside air in with the intake off just not nearly as much so maybe having the exhaust go off when the lights do it won’t get nearly as much cold air in as it was luckily for me I have my nursery tent to keep them in until I get it to where I want it and worse case scenario I can leave the lights on 24/7 since they are autos thanks for replying I appreciate it
Happy growing
Maybe try setting your lights to be off during the hottest time of day 
That could raise temps 4-5*
I got it under control now I think anyways, turning the intake fan off did the trick and the way it’s set up as long a the exhaust fan is on it’ll still pull fresh air in thru the intake duct even with the intake can turned off last night was the first trial run and the temp only dropped to 63 so hopefully it’ll be ok until summer gets here Thank you for the input guys I really appreciate you taking the time to give me your input
@Chasworks I did that last summer when my AC unit decided it was a good time to take a dump and it did help having my lights off from 8am until 8pm which also is non peak times for the electric bill so if your trying to save a couple dollars it helps with that too that was the reason I chose the 8 to 8 time frame instead of like 5 to 5 which was the time frame i use to always use for my photo period plants until the AC died anyways
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Can you put a heater in the tent if you’re unable to warm the room? Mine drop to the low 60s at night and get into mid to upper 80s at hottest point. I had to use a small heater in the ten when growing in my garage in the winter.
I’ve a temp problem. I am using a 100-150w led that has done OK in my 2 x 2 foot tent. After a bust the police cut all my wires. Just managed to salvage a fan my led and I tested a 600w dimmable hps. I know its a bit much but was hoping temps would be fine but they were nearly 90° I’ve raised it up and will keep trying but if temps stay that high I will take the hps out. Only running at 250w
I have a hygrometer linked to my phone so careful monitoring will be done. Anyone think this is overkill or will it work good?. Good news is humidity is low when they are on. From 70s down to 40s. But will likely shoot back up now. I’ll just monitor it but if there is anyone who thinks this is a silly idea then please comment/advise on what I should do
Sorry to hijack your thread pal
I don’t think 90s is a problem if you have adequate exhaust and circulation. Worst case unzip the door half way when its too hot or exhaust more hot air. I would definitely turn the exhaust fan up at night if you’re hitting 70 rh at night… If in flower you’d need dehumidifier at that.
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Yeah got one and on with it. Gonna experiment And see what happens
The de-humidifier should help with the temp too
@Damo1107 it’s all good my fellow grower as far as I’m concerned it’s anybody’s thread that wants or needs to use it at least you stayed on topic that’s all that matters 
good luck and happy growing to you all
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Thanks @JimiG1974
But tag @frogyrogy @Chasworks @laf6502.
Now I have had mega high lights off humidity before but this is my plan and it’s not working how I’d like.
1 lights on open tent door
2 set central heating to go off at lights on.
3 open a window at lights on and constantly run a dehumidifier.
Now it’s going from as low as 19°c to 36°c and rh from 30 to 92% not overly concerned about the 92 as no dew or condensation noticed but still a niggling thought. It’s more the 36+°.
Often seen rh that high but never had rot touch wood.
I have to have the dehumidifier outside tent as only 60cm2
Thanks guys ill be keeping a beady eye on em
Look OK?
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Personally from my experience anything under 50 causes problem… slow root activity…!!
I run my a/c and de-humidifier after week 2 in flower: the hi temp doesn’t seem to effect the plants that much if i don’t run the a/c but the humidity is another story! Makes drying and cure complicated! Even storage is effected by the hi temp hi humidity thats year around: good luck!
Weed does not like cold. Remember that.
I live in the Tropics i need the a/c to get it down to 80* and it helps with the humidity but i still need the de-humidifier to get the rh within range! Never Cold here!
Humidifier should always be outside the tent, that’s good . . . the easiest way to get a tent dialed in is to get the lung room right first. Keep in mind that any conditioning you do inside the tent is negated the moment your exhaust vent kicks in . . . unless you have equipment to dehumidify and heat or cool at the same or higher cfm as the vent is removing that air and replacing it with unconditioned air from the room.
They look good and healthy so I wouldn’t worry about it too much till you get to flower. I have run my tents in colorado in the mid to upper 90s with very low humidity (I live at 9k ft) and plants seem to adjust to the environment as long as it fairly consistent. No problems with healthy plants but I would rather deal with low humidity than high humidity 
