RH control help

Need some advice on controlling my humidity during the day and at night. I have an inkbird humidity controller and a small dehumidifier I purchased on amazon that doesn’t seem to work the best during the day I’m around 50-56% and at night I have a hard time keeping it down its been averaging 58-64% the dehumidifier I have you have to push one button to turn it on. Once the humidity is at a good range the inkbird turns it off but once the humidity rises it can’t turn on unless I open the tent and push the button. How can I get on top of this issue quickly I am growing autos and have roughly 4-5weeks left before harvest. Haven’t really had many issues lately but being in MI the temp/humidity swings have been ridiculous. I am also attaching an image of the dehumidifier I currently have.

If the dehumidifier has its own RH setting, use it and disconnect from controller.


I did a quick scan of the web page… it looks like this is either on or off, with no humidity control.


On / off it is. I wonder if you can use a dedicated timer to run at night when your RH is higher. If you have an extra timer, give it a try. I know I have a little LED I use to germ. seeds and I can not put it on a timer. It will not turn back on. Maybe your dehumidifier and my light has the same wiring.

You might also try just leaving the dehumidifier on all the time to see if it stays within a reasonable range. It’s not exactly a powerful device, so it probably won’t make your space too dry.


Is the dehumidifier in the grow area, or outside in a lung room?

The unit is pretty small. It probably can’t keep up with all the humidity contained in the warm daytime air.

As @TommyBahama said, I’d just leave it on 24/7. It’s hard to bring humidity down too far in late flowering unless you’re in the desert.


I’m with @Drinkslinger and @TommyBahama on this one. I have two 3 gallon dehumidifiers running constantly without any issues. Compressor type dehumidifiers can only go to 50% RH. They can’t physically go any lower.

I just got that one and put it in my tent. Since I’m pulling air in it really hasn’t dropped my humidity at all. I need to work on dropping the humidity in the whole room my tent is in. You may have the same issue

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Yes it’s inside my tent I’m having a hard time getting it to stay under 60% it’s been running all day!

I have it inside the tent running all day and I am having a hard time getting it to stay under 60% some reason at night is when my humidity will rise more than the day.

Yes I am running it all the time now and struggles to keep it below 60% currently

When the lights shut off, temps drop, rh rises.
I’m assuming you empty the reservoir just before light go off. How full is it in the morning?

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I will check today. Shall empty it and see how it is in the am, I’ve been solid around 55-58 so far today though.