Greetings Forum Folk!
I am about 7 weeks into this grow. 2 Blue Dream & 1 Do-Si-Dos autos. They are in their 2nd week of flower, though their appearances indicate a staggered timeline, with the DSD being the last to bud. So perhaps the 3rd week for one BD…
Here’s my situation and questions: Growing in a 3x3x6 tent in a small basement room. I am located in the Midwest, and in previous Spring/Summer grows I have struggled with temp & humidity levels. Battling with dehumidifiers and A/C unit to try to maintain recommended/ideal targets was always a back and forth ordeal. Won’t bore with details, but it just never worked out. And the cost of running those appliances didn’t justify the result.
So, for this grow I have committed to going with the conditions presented with minimal amending.
To date the temp has been consistent at 75-77F. The humidity range has been 50%-60% with it elevating during dark period to 65%-70%. I am on a 19/5hr light schedule to minimize the time in higher RH as much as I can.
To help try to minimize the hazards of high RH I have implemented fans for as much air movement as I can generate.
In the top portion of the tent I have four 6" circ fans - 1 in each corner directed downward running at their high setting (not all too forceful). I have an 8" oscillating fan blowing over top of canopy just enough to keep the plants moving a bit with the breeze. I also have 2 addition 6" circ fans set on the floor of the tent directed upward into the center of the 3 plants. These fans are on their low setting. Finally, I have a floor box fan set at its medium setting on a timer to go on only when light is off. All other fans are running 24/7. The box fan sits in front of the tent, and I have the door to the tent pulled back, and a screen door in its place. the screen door is in use all of the time to help moderate temps.
The outdoor ambient RH is usually around 60-70% +, and the basement is typically not far off that. There isn’t a window in the “lung room” to vent or draw from so I pull air with a 6" inline from an adjacent basement room.
I have read some discussions - not here - about higher humidity levels in flower not as disastrous as most information claims if other parameters can be managed. I don’t see any indications that these 3 are struggling now, or looking suspicious for mold or PM. But I’m sure the potential increases exponentially as buds develop.
My question: am I crazy & wasting time with this approach? Any feedback, or suggestions - other than ones of more appliances or room changes? Any info will be considered and appreciated. Thanks in advance for taking time.
I have a grow going now, flipped lights about 8 weeks ago, and have been in high humidity for months! I’m using an autopot system, first run with it, and my humidity has been upwards of 90% at times! I just did the 6 or 7 week defoliation, and now have the humidity down round 70%. No WPM yet, and I too have lots of fans pushing air around.
You should be fine as long as your leaves aren’t stacked on each other…water will condensate there and that could become a problem. But just watch them for that and you should be ok. Not ideal, but you gotta grow in what you can!
I have had success flowering in 65% Rh at 70-80 degrees. Not that I would recommend it but with good spacing, lots of air circulation, and a little selective defoliation it can be done if you just cant get the humidity down.
This area looks like it could become an issue.
@Spudgunner thanks for your info. I spend enough time looking in on these so I should be able to keep things in order. Thanks again! 
@Gl1tch thanks for your info. I think I’ll be able to keep environment in good order. Thanks again!
I grow in a midwest basement also. With those numbers your vpd doesn’t look bad at all. Ive grown successful in much worse conditions. You could always bump to 20/4 to later in flower that should bring your vpd up a bit in the optimal range. I have a small dehumidifier that doesnt use much electricity that i’ll throw directly in my tent if the humidity gets out of control.
Have the same issue. I’m outside in garage room.
First things first. Make sure you are getting accurate humidity readings. That was more of a chore than I thought.
Rest of advice is solid. You definitely want to try to get humidity down. Let me take a look at post again and I’ll maybe have more input.
If you aren’t going to dehumidify keep a steady breeze on them and you might want to try to raise the temp at lights out. That will drop humidity. You don’t need to be cooler at lights out. @Willum
@Formerbrew thanks for your input. I am getting my temp and RH readings from 3 sources - AC Infinity control probe & Govee hygrometer probe are both hanging in central location just within canopy. I have an addition hygrometer hanging with the probes for reference. The 3 are reading the same +/-. I also have one outside the tent in the room to keep an eye on entire environment. Thoughts on this configuration? Thanks again for taking time.
@Formerbrew temps don’t go too low in dark period - around 70-71F. I’ve read that is where problems can arise when a dramatic difference in temperature occurs. Thanks again!
@NorseRow Thanks for your info. If you’re also in the Midwest you know where temps & RH are heading…
I started this grow with 20/4 light schedule, just switching it a cple weeks ago when pre flower began thinking perhaps an additional hr of dark might assist with flower commencement. As things progress and the challenges increase I may go back to it.
I had a Vivosun small dehume until it stopped functioning last year. It was good for about a point, or 2. Might have to spring for another if things become radical. Thanks again for taking time!
Yeah. If you are ok when lights are on then it’s mostly that small temp drop raising rh. Plants also transpire at lights off but I think mainly spoke in humidity is due to the temp drop. Could you raise temp during light off ?
@Formerbrew I’m guessing temps are going to increase naturally very soon as outdoor ambient environment does so.
More than likely. I think without a dehumidifier you set a max temp you want to be at and minimize humidity by raising temp - not above 80. And keep fans moving on it. Also. Water at lights on.
temps during lights on rise to 78F frequently, so reaching 80 is not far fetched. I can edge the light pwer a bit. Thanks for the suggestions.
No problem. I think if you are careful to keep airflow between The buds that will help a lot too. If the plant is still pliable you can spear the branches so the buddies don’t touch each other as they grow.
yeah. of the 3 plants 1 Blue Dream is shorter and “stubbier” than the other two. That’s the one I’ll need to keep close tabs on. The other BD and the DSD are long, lean and pliable so I’ll be able to do just that. Along the way I’ll continue clearing out lower and inward growing leaves that hinder light penetration and air circulation.
Sounds like you got it. I have a long thread on my grows. I’ll try to get a link if you like to follow. I’m in there a lot if you have questions. Lots of knowledgeable people over there.
Just a follow up to the discussion and advice in this post…
still running these 3 in high RH in flower. 4th week in flower and temps & RH avg 76F/58-60% with light on (19/5hrs). As outdoor temps & humidity climb the conditions in basement increase as well. With running a dehumidifier in the lung room and venting its heat to another room I can manage temps in low-mid 70’s & mid-upper 60’s in RH%. Still running all of the fans throughout the tent mentioned earlier. And I take away some leafs obstructing light or airflow. So far we seem to be evading issues - specifically mold or PM. I’m hoping I can keep this on its tracks for another month or so
