Another first grow

Thats a good idea. I just went down and checked and its working really well just being in the room. Its dropped to 60% in just 3 hours. I will see how it goes for another few hours. I will pipe it straight in like you do if i have to.


That thing should do you good, give it 24hr to suck the moisture out of the room.

Remember if your growing in a room you dont want humidity above 50% or your going to get rot and mold in your house!!!
That’s why we suggest tents or having a dedicated exhaust and intake to control the humidity along with the dehumidifier


Ok, the humidifier is going and pulling a crazy amount (buckets full) of water from the air. I am trying to dial in the room and tent temps and humidity. The humidifier had been running for 12 hours or so and with the lights on the temps / humidity in the tent were 82°F and 46%RH. This morning when i checked (lights had been off 2.5 hours) my tent was 76°F and 50%RH. The humidifier has increased the temp in my room by 10°F. Is the temp vs humidity acceptable? @spyonyou @Nicky @Not2SureYet

I was changing the angles of my tent fans and one of the colas brushed on my arm while I was in there messing around. It was super sticky and my arm smelled very citrus for a while. I am starting to get real excited about being able to get this grow to harvest!


Most of my grow has been around 78-82*/50-55% for the days
Nights are a little cooler but humidity around the same.
I think you’ll be fine there.

PS, I’ve never had the opportunity to get ideal condions because I’ve always had to monitor and adjust…lol :joy:

Usually about 4 weeks in, somehow a few of my buds fall off into a brown lunch sack and dry for a week. I have no choice but to try them out!! :joy::wink::sunglasses:


I’m not familiar with F as I’m not American.
Download a VPD chart for cannabis with F on it and check.
Do you have a controller for the fan?
@spyonyou you need a controller

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Not sure what you exactly talking about F and controller?

F is for Fahrenheit.

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82F is just shy of 28C

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Ok, I understand the charts now i think.

If i want 45%RH, then I must lower my temperature to around 73°F (23°C). If my temperature stays at 82°F (28°C), then I must keep my RH at 55-60% for correct propagation. Doesn’t an RH of 60% considerably increase the chance of mold and bud rot?

Should I try and reduce my temps to be able to get the RH lower or am I ok at 82°F (28°C) and 60%RH?

@spyonyou @Not2SureYet @Hellraiser @Zee @kdawg @kellydans @repins12 @Jackie_Daytona


Sounds about right. I just add extra fans to help circulation when my RH is up a bit. So far so good.


Bud rot is a nightmare! As other stated air circulation helps prevent it.

Have you noticed water droplets on your leaves? Early signs of bud rot is moisture on leaves, cotton looking hairs around your pistols. The smell changes, goes from dank weed to almost no smell. Lastly if your trics don’t start changing. This is my experience…

Here is an example of early stage.


Sometimes it’s really hard to have a perfect environment I don’t let 5% worry me too much but it is very important to keep plenty of air circulation.


You said that you always have to monitor and adjust so I said you need a controller, that whay you just set the parameters and walk away lol.

@kdawg ty, was sorta a nudge for @Reitus to get his VPD chart as much as it was Its to early to do math or google conversion on days off

@Reitus you got the VPD chart figured out, just follow the stage of growth, you don’t need to worry about getting bud rot if your following a VPD chart and have good airflow. The chart won’t suggest your in the high humidity Durring late flower.


Good point. I better keep an eye one that. I am pulling a lot of air from my room though.

@Reitus, I snagged the chart there. That is the first I have seen in F. All the ones I had saved are in C

I am just offering this as info to my grow.
Normal temps for me are about 82 -84 Between day and night. My humidity on the low side is about 55% and the high is 70% average each 24hr cycle. I have ran a lot of grows in the 70% humidity range. As long as I had good air flow. I never once got mold. Once my plants get farther into flower. I will be changing my lights to on at night and off in the day. My dehumidifier adds a lot of heat too and I am in an open room. I want to run the dehumidifier this grow to see if I can get back to the super sugary looking buds.


You both have exhausted air going outside your house right? @Reitus

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get outta here with that! I have been having dreams about bud rot1 I just pulled a bunch more larf and leaves as directed by hellraiser. Im having trouble staying out of the red to get to 45rh.


I’m not overly concerned with the VPD chart, my starting humidity is usually low (live in the desert) so even using humidifiers it does not very high, my tents are usually in the high 30’s to low 40’s RH wise during lights on with temp at 77-79F and 50’s RH at lights off.

According to VPD charts, my plants are not at an optimum temp/RH ratio, yet I just pulled 2 lbs from my 3x3, so I don’t take VPD charts too seriously, best to have lower RH to avoid high RH problems like mold and mildew, which I’ve never seen on my plants in 30 years of growing.


So basically forget trying to get the temp down to get to 45Rh? Cause I dont think it is gunna happen in my setting. It might as temps are falling outside but it is getting harder and harder to bring down rh in the tent. I keep getting into the 1.66-1.86 on the vpd chart to get in the 40s.


Yeah, I wouldn’t worry about it, just keep RH as low as you can for that last month of flowering.


Thanks for the info everyone! I appreciate it.

@Nicky Currently the room with my tents is exhausting into my basement. I have an option to exhaust outside and will make that happen if I can’t get my temp down.

@spyonyou Haha! Yes, I have a few low hanging fruits that are going to be picked soon as well. I need to thin it out again anyway.

@kdawg @kellydans Can there be too much air circulation? I have 2 small fans hanging in the tent but could crank them up and really make some leaves (and colas) move if i wanted or need to.

@Zee Thanks for the picture of the rot. I have not seen any water droplets. I did have some moisture between some leaves at one point but that was right before I defoliated at the end if my veg cycle. I havent noticed any of that since then. I will be inspecting some buds real close here shortly to compare with your picture.

@Not2SureYet Good to know about you having some successful grows with a slightly higher relative humidity than average. That gives some confidence that I have not been that far off from where I need to be.

@Jackie_Daytona I feel you man! I have been trying to get everything just right. Most around make it look so easy. My inexperience has me fumbling through this first grow, heheh. Kudos again to everyone for sharing personal experiences and all the tips and tricks.

@Hellraiser Always a pleasure man. Thank you for stopping by and for the plethora of information I have gained by reading all your posts. You rock!


I run two circulating fans and if I need to with a 6 inch exhaust fan I can crank it up a little more.