Memory Form Mattress Mold
Wife discovered dampness under our memory form mattress. We were very puzzled. We thought someone breaks in and poured water there. Truly impossible. After hours of research with xah discord help, apparently it's common.
Here's our form mattress. (actually, it's a “mattress topping”, 3 inches thick (7.6 cm)) The dark area is where it's wet. It's the underside.

This is bought at Costco. Tempur-pedic form mattress topping. A year ago, for about $190.
Mattress absorbs your sweat at night. Apparently you sweat a lot. Most bed frames have ventilation. They are strips of wood or wire grids. Ours is a flat wooden board, that's the problem. It needs ventilation.
Here's our bed frame. Basically a wooden board. so it has no ventilation for the mattress.

Also, memory form types mattress are more inclined to grow mold. While spring types not.
Apparently, some form mattress has “Charcoal” for mold prevention. This one: Lucid 4 Inch Bamboo Charcoal Memory Foam Mattress Topper Buy at amazon
Image search for “mattress mold” will lead you to lots answers. This site is great ❰2022-01-17 ❮https://moldhelpforyou.com/mattress-mold/❯❱
Mattress Ventilation Solution
So, solution is buy a mattress ventilation pad.
This prevents mattress rot.


Fantaastic. Didnt know this existed. Wife friend a mover happened to have and gave us. Solved our mattress wet under problem.