How to Grow: Terrariums

Learn about making and growing terrariums indoors.

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Terrarium, Tree, GeometricIn the 1800’s a London physician called Nathaniel Ward wanted to watch an insect chrysalis transform into a butterfly. He placed it, with some soil, in a glass jar and sealed it shut. To his amazement, but not only did he see the butterfly form, but he also saw ferns and grasses growing in the bottom of the jar. The plants continue to grow in the sealed jar for 4 years without additions of water. It was the first modern terrarium.

Terrariums are popular again. Garden centers sell tiny houseplants that fit in containers from jars to aquariums. You can also get creative making terrariums inside glass cider jugs, salt shakers, holiday ornaments and tea cups. The first step is to decide whether it will be an open or closed system. An open system will need more care, while a closed

system is very humid and has more chance of disease forming. Add layers of gravel (for drainage), charcoal (for mold prevention) and moistened sterilized potting soil to the bottom of the terrarium so it’s about 1 to 2 inches deep. Add rocks, wood, sand and other objects to accent your theme.

Now the fun begins. Choose a plant theme, such as ferns, succulents or foliage plants. Choose plants with similar humidity requirements to match your style of terrarium and plants that will fit the space. Plants with low, dense foliage are usually the easiest to start.

After planting, mist all the plants and leave the terrarium open, even for the closed systems, for 24 hours. In a closed system you’ll only need to water every 4 to 6 months. In open systems water when the soil is dry. Only fertilize after one year. Place the terrarium in a window with bright, indirect light and enjoy!

From the Vermont Garden Journal on Vermont Public Radio