I have a 5 gallon rubbermaid tote with a tortoise sized hole cut in the side. I take the top off everyday and pour or spray water into it everyday depending on how much has dried. I also have a small heat pad under one side which evaporates the water above and keeps the air humid inside.
For my little South African leopard babies, I have a plastic flower pot, cut in half length-wise. Then I stuffed it with sphagnum moss. Every morning when I put out the food, I lift up the pot, gather up all the moss that's been scattered all over the habitat and put it back in place, then water it to make it moist again. I hate this!
So yesterday I went to Petsmart and in the guinea pig section, found a wicker house shaped like those half logs. Wicker = holes through it all over, easy to spray all over and get the inside wet! So I got some new sphagnum moss, took some fishing line and "sewed" it through the wicker and around the moss to keep the moss in place. I left a slight space at the bottom for the tortoises to be able to push under. So now all I have to do is spray the top of the wicker house and the water goes inside and gets the moss wet. And the moss stays in the house!! Now I'm a happy camper.
I was using a big piece of cottonwood bark with living moss on top of it and sphagnum under it, all wet all the time. There were also heat cable running through the floor under this, so it was running 99% humidity all the time. My leopard babies got big enough to not have quite enough room in there.
I bought a 13x13 floor tile, leftover at the flooring store, and had a guy cut it down to 11x13. It is the roof of my humid hide. Its edges rest on the edges of 4 plant pots, and I have a couple more plants set in front of it to reduce the size of the opening. Heat cables and wet sphagnum still inside the hide. I put a thin layer of soil on top of the tile and again added the living moss, and well as a couple of smaller plants. Maintaining the moss keeps the whole thing wet. It runs 99% inside all the time, the torts love it, and there's room for them to grow.