How to Build a Terrarium With Succulent Plants

A terrarium provides succulents with a suitable home year round. The self-contained growing environment requires little care once you build it. An open terrarium -- meaning no lid on the container -- works best for succulents, which don't grow well in high humidity. With a few basic supplies, you can create your own succulent terrarium in short order.

Every terrarium starts with a large clear glass or plastic container to hold the planting medium and plants. The size and shape is up to you -- almost anything from fishbowls to large vases will do -- but tall containers give your plants more room to grow. The succulents are easier to plant if you choose a container with a wide opening -- large enough to reach your hand inside. A narrow opening requires you to use narrow tongs or sticks to lower the plants into the terrarium. You won't need a container with a lid since the succulents need an open terrarium to thrive. If you don't already have a container that will work, head to a craft store where you'll find an assortment of large vases, jars and other glass containers. Clean the container thoroughly with warm, soapy water before planting. Rinse the glass well to remove all soap.

Since terrariums lack drainage holes, you need to create a base for planting that allows excess water to filter down to the bottom so the plants don't get too much moisture. Plan to fill up to 25 percent of the container with the base drainage and soil layer. Start with a layer 1 to 3 inches deep of aquarium rocks or gravel to create a drainage holding area. The depth depends on the overall height of the container. Add a layer of 1/2 inch layer of horticultural charcoal, followed by sphagnum moss or nylon fabric to keep the soil from falling into the rocks. Put in at least 1 1/2 inches of sterilized potting soil that is slightly moist.

When choosing succulents, pick varieties that are slow growing and stay small. Consider the light available where you plan to display your terrarium and match the succulent to those conditions. The Caucasian stonecrop (Sedum spurium 'Red Carpet') only grows about 3 to 6 inches tall, for example. It grows well in U.S. Department of Agriculture zones 3 to 8 and likes full sun. Decide how you want to arrange the succulents before you start planting. Larger plants often look the best at the back or in the middle. Fill in with smaller plants around the large succulents to create an eye-pleasing arrangement. Plant the succulents as you would in any container -- dig a small hole, position the plant and cover the roots with the soil mixture.

The newly planted succulents need some moisture to start. A misting bottle works well to add just a little moisture. You may need to mist the first two days to get enough moisture. It's always better to start with a little water and add more if needed since you can't pour water out of the terrarium without upsetting everything inside. Don't let more than 1/4 inch of water accumulate in the bottom of the terrarium. Since you'll grow your succulents in an open terrarium, you'll need to watch the moisture level. Position the terrarium where it will receive the amount of sunlight needed for the specific succulents you planted. Avoid areas near heat vents or other areas that are hot, as the extra heat can damage the plants.