Last summer, I wrote and photographed an article on making a terrarium, for Northern Gardener magazine. You can read the entire piece online, it’s the sample article on the homepage, from the Nov/Dec issue currently on newsstands.
I’ve learned a few things since putting the piece together–most of all, that I LOVE terrariums.
I built several of them over last summer for the article and I have learned that it really takes about three months for a terrarium to come into its own.
You may lose a plant or two along the way. Some fall prey to damping off, the scourge of seed starters, and the little plant just rots off at soil level. Swap out a new plant and you are good to go.
Terrariums are tiny gardens under glass; they transport us to another place and like nature, take care of themselves.
Terrariums are indoor gardening magic, like a bit of the forest floor brought to your buffet or bedside table. The little, light-filled orbs and boxes, packed with flora, are a visual treat, like a found nook in a hidden garden. Planting a terrarium is a tactile pleasure—a mix of sculpting, digging in the dirt and playing with a dollhouse and once assembled, they’re self-sustaining little ecosystems, watering and tending to themselves.
The dirt. The planting base of the terrariums is all-important and there are four levels, from bottom to top:
- A 1 to 3 inch layer of pea-sized river rock holds the drained water and looks attractive at the bottom of the vessel.
- A thin, ½-inch layer of horticultural charcoal on top of the rocks assists in drainage and also purifies the water, keeping fungus at bay, notably the one that causes damping off, the scourge of seed starters. Don’t skip this step as it also keeps the air in the terrarium pure, like the exhaust fan over your oven. Charcoal can be found at nurseries and garden centers that sell indoor plant supplies. It is also the same charcoal that is used in aquariums, so aquarium supply stores will also have it.
- A layer of sphagnum moss, available at nurseries and garden centers, as well as craft stores, will help keep the topsoil from leaching into the charcoal and river rock layers. It also has a wonderful organic look…apply liberally.
- 1 ½ to 2-inches of sterilized potting soil. Stay clear of soil that has fertilizer; you actually want to discourage excess growth.
Stick your nose in a thriving terrarium. The damp, rich, sweet, and humus smell, like the underside of a log, is intoxicating. It speaks to your gardening soul, calling you to commune with nature in an intimate way. Building a terrarium is fun and easy and once planted, you are left with a tiny, botanical museum piece that asks for little and gives much.
The vessel. I think the container makes the terrarium, so begin with a piece that you love; that speaks to you. Look for a container that you find beautiful and would have in your home for years. Both glass and plastic work, but glass plays best into the organic nature of terrariums.
Terrariums have gained popularity lately, so an assortment of containers is readily available–search nurseries, garden centers, craft stores and also home discount stores, like Marshalls and HomeGoods. Unique pieces can be discovered at thrift stores, antique stores and junk shops and consider discarded flower vases– the large ones with globular bases work especially well, and can often be found abandoned in the cupboard under the kitchen sink at work. And when all else fails, the old standby aquarium and fishbowl are perfect vessels.
- The container you select needs to create an enclosed environment and I have found containers with larger, more bulbous planting areas and smaller openings (like large vases or fishbowls), keep the moisture level the most consistent.
- If the opening is small enough you will not need to keep the terrarium covered, but if the shape is closer to a cylinder, you will need a glass cover. If you are drawn to a container that doesn’t have one, glass plates and bowls work and you can also have a glass piece cut at the hardware store, but edge it with thick cellophane tape to dull sharp edges.
- Treat your container like you would a jar for canning and wash well with a dish detergent to start out with as sterile a vessel as possible.
A note on degree of difficulty: What sometimes puts people off on terrariums is the idea of the botanical version of a ship-in-a-bottle. Plants growing in a narrow-necked container are dramatic, but I am a fan of creating a terrarium in a container that is easy to get your hands into, especially to begin with.