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[marzig]

I grow autos and have always had lights on 24 hours. I’d like to try a lights out schedule towards the later part of flower with lower temps and humidity to see how this affects quality. I know that as soon as temperature is reduced humidity can spike. I use their AI controller but don’t use the AI function because I have better control by setting my own automation’s.

Can anyone offer suggestions or how you control humidity when lowering the temperature with lights out? With or without any type of controller for photos or autos.

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Discussion

[yodagrows]

I use a dehumidifier or humidifier as needed to keep it under control.

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[marzig]

I have a humidifier in the tent and will be setting up my dehumidifier in the lung room today.

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[Newleaf]

The humidity will rise somewhat, but unless you’re dropping the temps dramatically once lights go out, it shouldn’t be anything you cant control with a controller and a proper lung room setup. If you have the ACI controller just make a seperate automation for night time. My lung room usually has the same humidty during lights on and off in most cases. It usually sits between 35-45% rh at all times due to having a 60 pint dehumidifier. It handles all the humidty added from the plants and humidifiers. When lights go out, my lung room is already set for the transition to night time.

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[marzig]

I hadn’t thought of creating additional separate automations for night time. That’s exactly what I was having trouble figuring out, thank you very much!

I run a window AC in my lung room which keeps humidity where I want it during day with the household central AC running. At night, the central AC doesn’t run as frequently so household humidity rises and the window unit can’t keep the lung room humidity down. I have a 60 pint dehumidifier too and I will be experimenting with that today. It will add heat but I shouldn’t need to run the window unit at max any more and will probably even everything out.

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[Newleaf]

Yea i have a night and daytime automation for both my exhaust fan and my humidifier. Dont mind the cold temps, I’m drying in it right now.

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[Newleaf]

Most of the time my exhaust fan turns on and off based on humidty. I usualy can control my heat from having a cool lung room and it exhausting from my humdity setting. Most of the time my high temp trigger is just precautionary. Not always though. In flower when the light is cranked all the way, ill use the high temp trigger to control my exhaust.

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[marzig]

I’ve got it all set up and running it for night right now. Figured I wanted to be awake to monitor it and it’s also the hottest part of the day. Humidifier quickly got the lung room humidity down to the 40s. Humidity is now no longer a problem. Heat is the main problem for me in the summer so I’m controlling exhaust fan only by temp.

Set up night automations for exhaust fan, humidifier, and heater. Funny thing was while doing this, it explains multiple automations and how there can’t be any overlaps, lol. Always ran everything continuously so I didn’t pay much attention to this.

I’m just sitting here now watching, tweaking settings and toking.

Do you maintain the same VPD at night?

Thanks again!!

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[Newleaf]

My night VPD is usualy very close to my days yes. If anything its slightly lower, so a slightly higher humidity ratio to temp. My thoughts are this. Alsmost everywhere outside in the real world, most nights, VPD is lower than daytimes, due to the cooling affect of the day. Cool air holds less moisture than warm air, so usually at night time you get a slight rise in moisture percentage. I figure plants must have adapted to this, so why not copy nature? Nothing crazy though. Say im running 1.2 durin the day. Ill run like 1.0 at night

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[Unknown Member]

So, are your afraid humidity will be an issue? or is it an issue?

If the is no current issue, then pin this for next time.

You have an AI controller with an Ai connected controlled extraction fan? that should mitigate any issue unless you have high ambient Humidity in your lung-room.

24 hours of plant transpiration is more of a cause of humidity than a lower temp dark periods, the drop in temperature just allows for humidity to become a peristriate. Just keep your vegetation from rest on the walls and mind over lapping leaves that are resting on each other, and you should be good.

Keep in mind, a 20-degree swing is manageable, but a 10 Degree is Ideal.

Furthered, 24 hours of light is extreme overkill in flower and will negatively affect your yield, you should research DLI and conversely VPD. On the DLI aspect, even autos have a maximum level of radiation they can absorb and once that absorption rate is achieved the plant must then focus on rejecting and burning off excess photo-inputs as well as bolster the affected tissue with chromatic changes to reduce photo absorption, a good sign is leaf and bud darkening on the foliage that receive to most exposure.

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[marzig]

These new auto genetics from Mephisto, Speedrun, and Night Owl are able to thrive with very high ECs and PPFDs. In fact, they take off like rocket ships except the countdown starts from the minute they sprout.

I’m very familiar with VPD and DLI. Currently my VPD is at 1.15 and my EC is at 2.9, it was at 3.0 but I’m slowly ramping it down. With the EC at those levels you have to give them a lot of light. My PPFD is at 975 now, but will ramp down along with the EC as they get closer to harvest. I honestly don’t care what the DLI is, although I’m sure it’s an absolutely insane number. My buds and leaves aren’t showing any darkening or any other signs of stress.

My thoughts are, that by giving them a brief night period while reducing the temperature, I’ll get some nice color changes and increased terpene production.

Thank you for your well thought out input!

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[Culver-Creek]

Have any of you found a dehumidifier that can be controlled by the controllers? Seems like all the ones I see are not “auto on” after power is cut.

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[marzig]

Mine doesn’t have auto-on either. I’m hoping that running by itself in the lung room it’ll be close enough. I guess I’ll find out soon.

AC Infinity has several but I don’t want it in the tent and I’m not sure about controlling it in the lung room. Might be an option though.

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[jiimii]

I fought humidity issues constantly until I got the Spider farmer dehumidifier with 6 inch duct. Its the only thing I own that’s made by them…my lights and tent are Mars Hydro.

The dehumidifier sits outside the tent and has a sensor that you hang inside the tent. A 6 inch duct runs in the tent from the dehumidifier and I have it draining into a 5 gallon bucket I dump once a week, Hands down single best purchase I made for the grow. I lost 2 plants to bud rot last year and that’s not happening again.

From about week 7 on Ill set it to 45% humidity and it will fluctuate 5% up or down. It has an auto defrost mode and auto restart if the power should fail. Most important fact is that it uses an actual compressor and not a BS semi-conductor.

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[Newleaf]

The dehumidifier is usually set up in the lung room. So its hard to set it up with the controller in a tent with a different environment. I just bought a 60 pint dehu that i can controll from my phone, and allows me to setup different schedules.

• This reply was modified 2 months, 1 week ago by  Newleaf.

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[smokythebear]

ive run into the exact same thing over the last 4 years ive really tried to change or modify it , but what i have found,noticed ,noted and lost sleep on is the plant is doing it , with the correct VPD the plant will go through its own process and unbelievably it knows what its doing , i gave up tryn and worrying about it and i get some danky ass nugs

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[smokythebear]

actually never really noticed it until i started growing by VPD

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[marzig]

Understanding VPD, and the plants role in it, was the biggest turning point for me. Dankness and yields dramatically increased. Before that, I just tended to scoff at it’s importance and kept telling myself that I would get around to it later.

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[smokythebear]

so important isnt it

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