Remember that you need to plan where you will be placing this piece, and accordingly choose the material. The material used for outdoor furniture needs to be highly weather-resistant. You need not look for water-resistant material, but just opt for a durable and good looking piece, in case you will be placing it indoors.
As mentioned earlier, you can use the topmost surface as a workspace. The next level can be used to place potted plants. The last level can be used to place small hand tools and earthen decor pieces.