Choose a container that will blend with the décor of your home
Through every step of the process, be careful not to introduce
pests and pathogens into your terrarium, as this humid enclosed
environment is a perfect breeding ground. Wash your hands or
wear clean gloves while building and maintaining your
terrarium. Start with a very clean container. Wash it with
soap and hot water. Rinse well in cool water and air dry. If
you feel the need to use a commercial glass cleaner, keep the
lid removed and wait a few days before your initial planting.
This will allow time for all fumes to escape.
You will need a soilless potting mix with relatively low
fertility. Garden soil is much too heavy and will compact.
Before the potting soil is placed in the container, mix in some
charcoal. Just a handful or two is all you need, depending on
the size of your container. Charcoal
will add organic matter and absorb any chemicals or odors. The
tiny pores in the charcoal hold water and nutrients and later
make them available to the plants.
In the past,
people added a layer of rocks or pebbles to the bottom of the
container for drainage. This is no longer the thinking. Place
enough potting soil in your terrarium to equal the depth of the
largest root ball of your chosen plants. This soil should be
just damp, not soaking wet.
When it comes to choosing plants, start with the adage that all
gardeners know: right plant, right place. Most that work
best are either moist woodland or tropical plants.
Succulents and cacti do not make good terrarium plants; save
those for your open terrarium or dish garden. Choose small
slow growers or naturally dwarf plants that will fit into your
container with room to spare. Remove any dead or yellowed
leaves before planting. Moss, lichen, and ferns are
natural choices for a terrarium because of their fondness for
moisture and their ability to thrive in dim settings.
Choose plants with similar light and moisture requirements for
the same container.
Your terrarium must not be placed in direct sunlight. It
will cook. The preferable location is in a bright room or
near a bright window. Let your knowledge of light
requirements for houseplants guide your decision.
Tools for Terrariums
You can purchase dedicated terrarium tools or make your own out
of things you have around the house. A long-handled
kitchen spoon is a good substitute for a shovel to create a
pocket in the soil at planting time or to remove a plant later.
A cork attached to a skewer or chopstick with a rubber band
creates a great tool for tamping down the soil after planting.
The fun part is, of course, creating the design. A single
specimen can be extraordinarily gorgeous when the right plant is
paired with the right container. For terrariums with
multiple plants, you’ll want to choose plants of varying heights
with different foliage, form, and texture.
A consideration with plant
placement concerns whether it will be viewed from only one
vantage point or from every direction. As with a garden bed, if
you will be viewing it from every direction, plant the tallest
plant in the middle with lower ones near the sides and
low-growing “groundcovers” (like moss or baby tears) blended
in. If it will be viewed from only one direction, then the
tallest plant goes in the back. You may even decide to slope
the soil so that it is deeper in the back.
Designing a Terrarium
Lay out your design
outside of the terrarium. Do not choose too many variegated
plants or too many plants with colored foliage. This is a small
space – more is not better. This is also a good rule for adding
non-plant materials. It’s wonderful to add a stone or twig or a
curved line of pebbles to designate a path.
When your installation is complete, clean off any dirty leaves
and the inside glass of your container. A soft clean brush or
paper towel may work, or you can use a mister. Your terrarium
will need to be watered, but you must go gently here. The
misting may be enough. It is easy to add a little more water
later, but difficult to remove any excess. Your goal is to
establish a rain cycle within the terrarium. The first several
days will require your attention. If there is water on the
foliage, let it dry before placing the lid on the terrarium.
Once lidded, there should be condensation on the inside which
rolls down and waters the soil. The goal is that the
condensation should look like a light fog. Anything heavier and
you’ll need to remove the lid for a day or two.
Now that you know how to create a closed terrarium, go dig in
the dirt and have fun with it. Create a beautiful new living
feature for your home or office that you can enjoy year-round.
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