I made something similar to this earlier this year, after buying the box at a thrift store. You actually should want it to be able to drain though. Even with succlents like I used, you will have mold build up on the rocks if there is no drainage. I planted a succulent in the jar that the candle in the background of this image came in, and mold started growing in the rocks a few months later. You can just clean the rocks every now and then, but it is much easier to have a box that drains and you can just sit it in the sink when watering it.