How to Make a Terrarium | Gardens Under Glass

Which Plants Are Best for Terrariums?

February 20, 2019
Terrarium

Terrarium with tropical succulent and cactus plants

Svf74/Shutterstock

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If you need an escape from winter cold but can’t afford a ticket to the tropics, why not try your hand at creating a terrarium, a miniature garden under glass? Anyone can have a terrarium! They’re great to decorate a house, apartment, or even office.

The Return of the Terrarium

Originally popularized during the Victorian era in the form of the Wardian case, today, terrariums and bottle gardens are making a big comeback.

It’s easy to make a gorgeous mini-garden out of any clear container. An old fish bowl, cookie jar, giant brandy snifter, or wide mouthed bottle will make a fine indoor garden. If you are using an old aquarium, test it for leaks first; they can be fixed with silicone sealant to make it watertight. Just a hint: Planting is easier if you have chosen a wide mouthed container!

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Image: Making a terrarium. Credit: Ivan Kislitsin.

How to Make a Terrarium

To get started, you’ll need the right supplies:

  • A clear container of your choice
  • Pebbles, small river stones, or expanded clay balls used in hydroponics. 
  • Charcoal (activated charcoal, horticultural charcoal, or lump charcoal will all work as long as the product does not contain any additives)
  • Potting soil (choose a well-draining soil to prevent it from getting compacted and waterlogged)
  • Decor (wood, rocks, or other decorations)
  • Plants (more on this later!)
  • Planting tools: a spoon, long-handle tweezers, or even chopsticks can come in handy when planting in thin-mouthed containers

Instructions

  1. Cover the bottom of the container with at least 1 inch of pebbles (or an equivalent material) for drainage. This drainage layer is used to keep the soil from becoming waterlogged and swampy.
  2. Add a thin layer of crushed charcoal to cover the pebbles (this helps with filtration).
  3. Add at least 3 to 4 inches or more of sterilized potting soil on top of the charcoal, depending on the size of your container and the size of the plants.
  4. Now you get to be creative and design your miniature landscape. If your container is large enough, make hills, lakes, and paths or add rocks, statues, and driftwood.
  5. Finally, it’s time to plant. Look for dwarf or low growing plants that all have the same requirements for light, humidity, water, and temperature.

Combine different sizes, shapes, colors, and leaf textures to make things interesting. Select plants that don’t mind wet foliage, such as moss, ferns, or prayer plants. Plant a woodland scene, use flowering alpines, get carnivorous, or go totally tropical.     

Which Plants Grow Best in Terrariums?

The two most important factors to consider when choosing plants for terrariums are their mature size and their ability to tolerate moisture. Some plants that grow well in terrariums are:

  • Ajuga
  • Aluminum plant
  • Artillery plant (Pilea)
  • Baby’s tears
  • Bird’s nest sansevieria (for open terrariums only)
  • Bloodleaf (Iresine herbstii)
  • Bromeliads (young plants only)
  • Button fern
  • Carnivorous plants: Venus fly traps, sundews, butterworts, cobra lilies, and tropical pitcher plants are all carnivorous plants that like humidity. However, most non-tropical species need to experience a period of colder weather (dormancy) to thrive.
  • Chinese evergreen (young plants only)
  • Creeping fig
  • Earth star (Cryptanthus)
  • Flame violet (Episcia dianthiflora)
  • Mosses
  • Oxalis
  • Pellionia
  • Peperomia
  • Polka-dot plant (Hypoestes)
  • Rabbit’s foot fern
  • Small-leaf ivies
  • Spike moss (Selaginella)
  • Strawberry begonia
  • Swedish ivy
  • Variegated aloe (for open terrariums only)

Most nurseries offer a wide variety of “terrarium plants,” though these are more often than not just young plants that will eventually grow too large for your container. In general, look for plants that like a tropical climate and that grow in a creeping, vining, or clumping manner. 

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Image: A small garden in a round glass terrarium with Dionaea muscipula, Venus Flytrap. Credit: Supa Chan/Shutterstock.

Since cacti and succulents can’t tolerate humid conditions, they are not good candidates for a closed terrarium. Save them for an open dish garden, which can be created in the same fashion as a closed terrarium—just be sure to use a succulent soil mix for good drainage!

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Image: Mini succulent garden in open glass terrarium. Credit: Dzina Belskaya.

Taking Care of Your Terrarium

Once established, your terrarium will be very low maintenance. 

  • Don’t plant too closely, allow some room for growth. Your terrarium won’t look instantly lush; plants need time to adjust and settle in.
  • Water after planting; soil should be damp but not soaked.
  • Place your terrarium where it will get bright light but not in direct sun, which will cook your plants. Artificial light is excellent.
  • Leave the terrarium open for a few days while the plant leaves dry off, then put on the cover and keep a close eye on the plants.
  • Excessive condensation, moldy plants, and limp yellow leaves are signs of overwatering. Open the cover and let your terrarium dry out a bit if that occurs.
  • No condensation and plants with wilted leaves are signs of underwatering. Check the soil and water lightly if it seems dry.
  • Leggy growth is a sign that your terrarium is not getting enough light.
  • It’s normal to see small insects crawling around in your terrarium after a while. Usually, these are springtails, which are beneficial insects that help to break down dead plant material. They’re your terrarium’s clean-up crew!

Sit back and imagine yourself strolling through your mini-landscape, enjoying the greenery and humid air. Spring will be here before you know it!

About This Blog

Get inspired by Robin Sweetser’s backyard gardening tips and tricks. Robin has been a contributor to The Old Farmer’s Almanac and the All-Seasons Garden Guide for many years. She and her partner Tom have a small greenhouse business and also sell plants, cut flowers, and vegetables at their local Farmer’s Market.

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