Note: Succulents and cactuses are better for open-style terrariums and require different growing conditions. Step 3: Start with a draining base layer Lay a 1/2-in. sand bed into the container.

With terrariums, there are two choices. Either leave the terrarium open to the elements or close it up with a stopper. If you aren't a botanist, it isn't immediately obvious why you'd choose one ...