After looking through various cigar humidors and old furniture pieces, I had a hopeless feeling that nothing would be worth it. I was saddened to think that my pu-erh would be dry-stored for it's entire fermenting life...
That hygrometer is reading a "comfortable" 52% relative humidity. Not comfortable for the pu-erh, I'm afraid. I got to thinking that I should build my own enclosure. Well, not having any good wood for the job, I decided to go for the next best, cardboard.
Yep, that's right, 100% cardboard paneling...
That's the front, with at least a little bit of aesthetic bettering done.
You'll notice that all the cardboard ended up with plastic wrapping all over it. This is because the cardboard alone made the chamber even more dry by absorbing all the excess moisture that my pu-erh needed. So I wrapped it, and in doing so, solved the problem.
As you have already spotted, I had to add a fair bit of water to the environment. I started with just a very small bowl which turned out to not be enough, and I ended up with this setup...
...Which did the trick. :)
I made a graph on the relative humidity levels. It starts a bit chaotic because I was excitedly pouring hot water into the bowl to raise the humidity. The first steadying is marked by the switch to leaving the water at room temperature. The second change (for the better, into the target range), is when I changed from the small bowl to the three larger vesicles.
The graph is clickable for an enlarged version.
As the graph shows, the numbers are looking better. Now my pu-erh and I can rest comfortably.