Answers to Your Questions Terrariums

Answers to Your Questions: From Aquarium to Terrarium

Want to turn your aquarium into a terrarium? Here’s some advice on choosing the right plants and creating the right growing conditions.


I’d like to convert a 25-gallon aquarium into a terrarium. However, I’m hesitating between a wet environment, in which to grow plants such as orchids, or a dry environment for cacti. I’d appreciate your advice on choosing the right plants and setting up the right conditions (soil, lighting, temperature, etc.) for cultivation and growth.

Photo: Hasret Sonmez 


Above all, avoid reproducing a dry environment. Arid-climate plants also generally like bright light, and if you put a terrarium near a sunny window, the plants will cook. There’s a limit to how much heat even a cactus can tolerate! Also, air stagnates in a terrarium and remains very humid, which is dangerous for cacti.

Orchids, too, are generally not good terrarium subjects. There are exceptions, of course, but for most orchids, a terrarium is a poorly lit and ventilated environment.

Photo: Karolina Grabowska

What goes well in terrariums are plants that tolerate shade (you really need to put a terrarium at a good distance from any sunny window) and very high humidity. Ferns, selaginellas, creeping figs, sinningias, pileas, etc., will be very happy here, and can be used to create beautiful landscapes. Caution: look for miniature varieties, as growth quickly becomes overflowing in a terrarium where, pushed by high atmospheric humidity, plants grow at an accelerated rate.

As for requirements, here’s a quick summary:

  • houseplant potting soil with activated charcoal, perlite or vermiculite;
  • no drainage layer;
  • indirect lighting;
  • normal indoor temperature;
  • Little or no fertilizer;
  • Water sparingly, a few tablespoons at a time, and only when the soil turns pale;
  • Don’t be afraid to prune invasive plants.

Larry Hodgson published thousands of articles and 65 books over the course of his career, in both French and English. His son, Mathieu, has made it his mission to make his father’s writings accessible to the public. This text was originally published in Le Soleil on March 1, 2009.

Garden writer and blogger, author of 65 gardening books, lecturer and communicator, the Laidback Gardener, Larry Hodgson, passed away in October 2022. Known for his great generosity, his thoroughness and his sense of humor, he reached several generations of amateur and professional gardeners over his 40-year career. Thanks to his son, Mathieu Hodgson, and a team of contributors, will continue its mission of demystifying gardening and making it more accessible to all.

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