When I first got into terrarium gardening, I thought it would be simple. And in some ways it is. Put in dirt and plants and you have a terrarium. But that garden won’t last long unless you know how to do it right. Over the years growing these little gardens, I’ve picked up some helpful terrarium gardening tips I wish I had at the beginning.

Growing a Terrarium

A terrarium is simply a container garden that is either entirely closed or mostly closed. A fishbowl, for instance, can be a terrarium, although it is open at the top. A cloche makes for a good closed terrarium. You can also find Victorian-style terrarium gardens, made with panes of leaded glass and resembling miniature houses.

A closed terrarium is like a greenhouse, holding in moisture and warmth. Only certain plants will thrive in this environment. An open container allows for a little wider range of plants, even succulents or cacti that normally need a dry environment.

Important Terrarium Gardening Tips

Learn from my mistakes and accumulated garden wisdom when it comes to creating a lasting terrarium. It requires a fine balance to get this just right, but keep in mind that almost no closed garden will last forever, so if you get a few months out of it, consider it a success and then start over again.

• Choose the right plants. For a closed or mostly closed container, think tropical. Plants that like humidity and heat will thrive in this environment. Examples include aluminum plant, peperomia, polka dot plant, pothos, starfish plant, and spider fern.
• Use indirect light. These tropical plants are used to the filtered light of a rainforest. Don’t put your terrarium in bright light.
• Use moss as “grass.” Moss grows well in terrarium gardens because they love moisture. Find sheet moss at your garden center and use it as the base for your plantings.
• Allow for drainage. Unlike a plant pot, your terrarium won’t have drainage holes. Put a layer of pea gravel or activated charcoal in the bottom, with the growing medium on top, for drainage and to avoid soggy, rotting roots.
• Use coir. You can use potting soil for the growing medium, but I have found that this coconut husk product is better for preventing soggy roots. Soak it well before putting in the terrarium.
• Variety looks best. If you have room for multiple plants, vary the colors, textures, and leaf sizes for the best overall appearance.
• Use the right tools. A terrarium with a small opening can be difficult to plant. Use tweezers and kitchen tongs to assemble your garden and be patient; it can take a while to get everything right.
• Check daily. The biggest problem in most terrarium gardens is excess moisture, which leads to rot and mold. Check on your plants every day to catch these problems early and to adjust watering as needed.
• Air it out. If your closed terrarium does get too wet, leave it open for a day or two to rebalance and dry out a little. Sometimes, I find I need to open the top just a crack to get it right.