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Terrariums: How to Create and Care for Them

A Brief History of the Terrarium
The concept of the terrarium was discovered accidentally by Nathaniel Bagshaw Ward in the mid-1800s. Dr. Ward was a physician with a passion for botany. He also kept various preserved insects and the cocoons of moths in sealed glass containers. A fern spore was inadvertently enclosed in one of those vessels and it germinated and grew for several years. Dr. Ward saw the possibilities as a way to grow plants that may be sensitive to harsh environmental conditions. He published a book on his experiments in 1842, On the Growth of Plants in Closely Glazed Cases. Containers made with metal-framed glass panes became known as Wardian cases and were very popular for the rest of the Victorian era, up until the early 1900’s. The 1970’s saw a resurgence of terrarium use, and they are becoming popular again today as habitats for pet frogs, miniature landscapes, and greenhouses for tropical plants.

Components of a Terrarium
Almost anything that is open to light, holds water, and traps humidity can be used as a terrarium. The larger the container, the greater the opportunity you have for plant selection and landscaping. Traditional cases include glass bottles, fish bowls, and bell jars. Today, many use fish tanks or glass enclosures from pet supply stores specifically designed for housing plants and small animals.

Ideally, your light source is either natural (but not direct, so you don’t bake your plants) or flourescent plant lights. The newer, compact flourescent bulbs and some compact halogen bulbs can be used at a slight distance from the glass, but take care that there is no excess heat buildup.

Air and Water
True terraria are mostly or completely enclosed, so the air and water recycle. Most setups used today are partially open to allow for air circulation. This helps prevent fungal growth. A totally open setup would be a dish garden, which is more of a typical mixed plant
container than a true terrarium. Water should be added only when necessary to avoid keeping conditions too wet. The high humidity will keep the water needs of the plants low, and the plantings will take a long time to dry out.

While terrarium size influences the types of plants you can grow in them, typically the purpose is to choose those that stay small enough not to outgrow their enclosure. They should also need the same light and moisture levels, which typically consist of low to moderate light, high humidity, and consistently moist soil.

Potting Mix
Peat moss makes up the bulk of most potting mixes and is largely sterile; many pre-made mixes add Perlite (sponge rock) for aeration and Vermiculite for water retention. New mixes are starting to use coconut fiber as an alternative to peat moss. In either case, the goal is to use a mix that drains well and doesn’t stay too fertile, as you don’t your plants growing so much that they need to be moved. A helpful additive is activated charcoal, which absorbs excess fertilizer, salts, minerals from tap water, and general odors. Some people use a gravel or other materials beneath the potting mix to aid in drainage, though it’s not necessary.

You can landscape your terrarium in several ways — create hills and valleys, top dress with moss (living or dried), add twigs or branches, decorative stones or miniature figurines. More elaborate setups
include trickling streams of water and small waterfalls.

Terraria are very low maintenance once established. As older plant leaves naturally die off over time, remove them by hand or with tongs or tweezers to prevent fungal problems and keep the plants looking fresh. Watering and fertilizing will be infrequent.

Plant Choices
A great many plants can be used in terraria, but these are some great plants to look for. Most are terrestrial, but those that can grow epiphytically (with their roots exposed and not in soil) can be mounted on bark, twigs, or hang suspended in the enclosure.

  • Begonia (especially rex types)
  • Pilea
  • Peperomia
  • Gesneriads, such as Saintpaulia (African Violet), Episcia (Flame Violet), Sinningia, Alsobia, and Chirita
  • Ferns, such as Pteris (Ribbon Fern), Adiantum (Maidenhair Fern), Asplenium (Bird’s Nest Fern), Pellea (Button Fern), and others
  • Aroids, such as Alocasia, Philodendron, Scindapsis, Epipremnum, Pothos, Syngonium, Nephthytis, and Anthurium
  • Carnivorous Plants, such as tropical Pitcher plants, tropical Sundews, and Butterworts
  • Selaginella
  • Dischidia and Hoya
  • Bromeliads, including Cryptanthus and Tillandisia
  • Orchids
  • Ruellia (Monkey Plant)
  • Fittonia (Nerve Plant)
  • Hypoestes (Polka-dot Plant)
  • Ficus pumila (Creeping Fig)
  • Pellionia (Watermelon Vine)
  • Soleirolia (Baby’s Tears)

Stephanie Fleming was raised at Behnke’s Nurseries in Beltsville. Her Mom, Sonja, was one of Albert & Rose Behnke’s four children. She was weeding from the moment she could walk and hiding as soon as she was old enough to run, so many weeds, so little time. Although she quickly learned how to pull out a perennial and get taken off of weed pulling duty.

This Post Has 3 Comments

  1. My brother bought me a terrarium for Christmas, but so far I haven’t put any plants in it yet. I have been to behnke’s to look for plants for it, but it has just been too cold to buy any house plants. I like the idea of carnivorous plants. Can you grow carnivorous plants in an enclosed container? Does Behnke carry pitcher plant?

  2. Carnivorous plants can be kept in a terrarium providing they get the high light levels that they need.

    I have maintained Venus Fly Traps in a partially closed 10 gallon aquarium with the individual pots nested into several inches of perlite. Water was kept about 1/2″ below the pots and the aquarium was in a greenhouse under 40% shade. They did great and are alive many years later! However that is not a pretty arrangement.

    I like to grow Butterworts (Pinguicula spp.)and Lycopodiums (not carnivorous,but difficult in room humidity) in a similar arrangement.

    In a more traditionally planted terrarium, you might try some of the very small Nepenthes, but even the small ones are vigorous growers.

    Perhaps this is a question for one of the specialty plant Face Book groups, either terrarium growers or carnivorous plant folks.

    Good luck!

  3. Thank you for your reply. I think I will try Venus fly traps and butterworts. Since it is warmer today it will be a good time to stop by Behnke and get some.

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