Humidity typically should be in the 40-50 range. 20 is pretty low. A temporary fix would be a bucket of water filled to the top. Or wet a towel and hang it in your tent, but not dripping wet, and that’s assuming you’re in a tent. The towel will dry out in about 3-4 hours, so you have to repeat it once it dries, but it is a quick fix, and works pretty fast. I had to do both at the same time before my humidifier came in.