Almost all indoor bonsai require high humidity for healthy growth in the room. One way to achieve this is with undertray filled with gravel that is kept moist. The rising humidity reduces the evaporation of the bonsai and thus extends the watering intervals. These ceramic undertray come from China. They are made by the casting method and are fired at low kiln temperatures. Water should not be allowed to stand in the undertray, as they are not 100% leak-proof. These standard undertray may have slight tolerances in shape and color.
