How To Use Progressive Web App aka PWA On 420 Magazine Forum
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I have experimented with hanging wet towels, and setting several full 5 gal buckets of water in my tent. Neither did anything appreciable to raise my RH. I bought a 2gal ultrasonic humidifier for about $45US. I fill it every other day when on high and it keeps my tent 4x8x8 ~52% max. One of my best buys so far as my photo plants seem to demand the higher RH.
Just keep a bucket/container of water in the grow area. As it evaporates the humidity in the room will rise.