Humidi-Grow trays are useful & versatile. As their name implies, they release humidity into the air. This is great for both the bonsai & the moss. The grid is removable, and if your bonsai pot is shallow enough, you can bottom-water it right in the tray. Just lift up the grid, and sit the bonsai pot into the water. When done, replace the grid and the excess water drips back into the tray. On occasion a walk in customer will ask if it can support a heavy bonsai. While I DO NOT recommend doing this at home, I put a HT101 tray on the floor and stand on it (I am 180+ pounds). Humidi-Grow Trays are available in six sizes. I recommend them very highly.