Winter Gardening Indoors with Terrariums
Terrariums can be opened or closed. Open terrariums are great because the “high sides” of the glass provide higher humidity for plants, and seem easier for the beginning gardener.
By Ellen Barredo
This article was first published in The Gateway Gardener Jan/Feb 2011 issue
One of my first jobs in the field of Horticulture was planting open terrariums. Terrariums are great gifts for teachers, hospital patients, and are great family projects!
Terrariums can be opened or closed. Open terrariums are great because the “high sides” of the glass provide higher humidity for plants, and seem easier for the beginning gardener. The open terrarium requires more frequent watering, but danger of disease buildup is reduced. The closed terrarium is a little more challenging but can be a learning opportunity as one can view the water cycle in action and if set up properly will require little maintenance.
If one spends a little time shopping, interesting glass containers can be found in many shapes and sizes. Try to choose one with very clear glass and without bubbles which can obstruct the view. Most terrariums benefit from strong indirect light, keep this in mind when shopping for your glass piece.
You might go to the yard to hunt for rocks, sticks, wood, seed pods or bark to use as decorations. Perhaps those trinkets picked up on vacation or at the local thrift store. Ceramic figures, frogs, mushrooms or snails help a natural setting. The materials added are a matter of individual taste. However, use care to avoid too many accessories. The terrariums decor can be switched to reflect the holiday seasons and birthdays.
You will need these supplies to build your terrarium:
tongs (surgical type/long) or chop sticks
funnel made of stiff paper
long bamboo stick with a cork on end for tamping
scissors long bladed
The possible choices of plants to use in a terrarium are those that tend to be small and slow growing naturally. Faster growing plants will need more pruning and may at some point need to be removed from the terrarium. Consider location when choosing plants for a terrarium, consider the location for the terrarium. Do not place in direct sun. Strong indirect light is best. The design process of a terrarium is simple. You will need one vertical element, several rounded, and several creeping. Size of the container dictates how many plants. When in doubt use less.
Time to shop for plants and supplies!! Why not take a friend. Often the supplies and even plants can be shared and reduce the overall cost of the terrarium. A plant list is included in this article.
*Clean your container and dry it.
*Create the bed. The soil layers are one of the most important steps in ensuring success with a terrarium. If you prefer NOT to see the soil layers you can line the sides with sheet moss before starting the soil building process. Rinsed gravel/pebbles should be placed in the bottom of the container, then place a layer of rinsed charcoal to cover gravel, and next a layer of sphagnum moss or a large coffee filter, which prevents soil from washing into the drainage area below. Quantities of each layer will vary because the size of the container used will vary. Next comes the soil layer; use a high quality cactus mix. The soil should be moistened prior to adding to the terrarium. It is preferable to use distilled water when moistening the soil. The soil layer depth should be appropriate for the size of the container.
* Add plants and accessories. Arrange your plants and accessories outside of the terrarium prior to placement in the terrarium. Remove plants from their pots removing extra soil, loosening roots and trimming if needed. At all times try to keep the glass as clean as possible. You may wrap the plants in a paper cone to help drop them inside the terrarium following your design plan. Reach in nestle the plants in and make sure they are firmly placed in the soil layer. Tamp down the rest of the terrarium soil floor to make it firm. It is time to add your accent items! The last step is cleaning the glass. You might use a mister and sponge paintbrush to dry the glass.
*Tips and Maintenance. From time to time you may want to open a closed terrarium and vent ½ a day. This allows one to remove old dead leaves, trim, mist with dilute fertilizer and to clean the interior glass. Please remember to rotate the terrarium regularly.
Supplemental light can be used for terrariums, such as under-the-cabinet LED lights, which are quite useful for terrariums. Fertilizing should be minimized due to the confines of the container, but on occasion and especially with flowering plants, it might be necessary. As a terrarium ages it will be more critical to fertilize.
Suggested Terrarium Plants
Mini African Violets – a bloomer
Mini Begonias – a bloomer and foliage accent
White Veined Fittonia – foliage accent
Neanthea Bella Palm – vertical accent
Variegated Creeping Fig – a creeping foliage accent
Mini Kenilworth Ivy – a creeper with beautiful foliage
Acorus minimus aureus – cute clumper with yellow foliage
Ellen Barredo was a certified Missouri Certified Nursery Professional with more than 30 years in professional horticulture, and contributed articles to The Gateway Gardener for 10 years. She now lives in Texas and is learning about the new world of horticulture there.