I've tried everything and my humidity is STILL 20%

Humidity decreases with airflow. If you have an intake and exhaust fan for your space, they are working to equalize humidity between the intake air source and your grow space. To make humidity you need a fixed volume of air, a water source, and a heat source. The humidifier is giving you the latter 2, meaning that I think your low humidity is coming from the high volume of air going through the space, relative to the amount of humid air coming off your humidifier.

You can use a mister to temporarily increase humidity in your space, but you will likely want to balance your intake flow with your humidity output.

ps. I thought dry was better. I only worry about humidity when taking a clone, and to solve that, I put a clear plastic container over it, with water misted inside the plastic container. No airflow under the container, plus heat and water = high humidity.

 

Try a 120mm PC fan + 44oz Cup of Water + Microfiber towel; worked for me. Keeps RH around 40% and a bit lower at night (lights out)

 

Are you certain your hygrometer is accurate? You can check by placing it next to a bowl of water and covering both with plastic. The humidity should rise well beyond 20% fairly quickly.

 

I would probably use a heated pad at that point, but I can verify my space was warmer when I had aluminum foil as my flooring. Have you considered adding more lighting to increase heat?

 

put a fan blowing at a bowl of water, give it a few hours should raise it slightly

 

right now i have the choice of... mold and normal RH, and no mold and around 20% RH.
i'll take the latter of the two any day. in MY entitled opinion, 20% isnt anything to freak out about, but thats because where i live, RH is like 90% 9-10 months outta the year, is i appreciate the temporary drop.

 

I'm in a similar sitatuion. 3 weeks into my first PC grow, things are goin well however my humidity won't ever peak above 20% and my temps stay at 79 degrees. I have the option in my vent system to add another 120mm outtake as well as another 120 intake if needed as I go further along with my microsog system.

I assumed that the lower humidity for growing was fine but wasn't sure, for when I took my seedlings and eventual cloning the saran wrap with a few holes poked in worked great for me in the same unit at the start.

 

If the plants are growing, just let it go and keep the air flowing. The plants themselves will eventually raise the humidity.

I agree that you'll only need to worry about too high humidity during late flowering.

 

If you want a cheap humidifier go to like walmart or walgreens or target ... or any major store and buy one of those vicks warm air humidifiers. They are like 20 bucks, I buy a new one every year cuz I hate cleaning them XD

 

The down side there is that it will also warm your air, which is about perfect at 79. I think you're better off with too dry over too warm.

BTW - For $42 at Walmart you can get an ultrasonic humidifier that doesn't create heat and doesn't use a filter. I bought one for my room, which was under 30 RH at the time. Now that the plants have grown, it always between 50 and 60 with no humidifier. The humidifier is now in the living room and my wife's itchy skin issue has gone away.

 

This just in... If you're still hell bent on raising your RH...

My son told me tonight that mushroom growers use perlite to humidify their grow chambers. I checked out a couple of mushroom sites and they say that perlite is like magic for transferring moisture into the air.

Get a small bucket or bowl (more surface area = better) put at least an inch of perlite in it and try to keep the water level in it to 1/2 inch below the surface of the perlite.

If you want to give this a shot, I think it might actually work well. I'd be interested in the results.