I’ve had a couple of those beautiful Edwardian Case Terrariums sitting around my home for years. You know the ones; they look like elaborate plant conservatories or greenhouses that were shrunk by the wand of a fairy godmother. You can find them in all sorts of places—vintage shops, eBay, estate sales, and surely your grandmother's attic. I never really "planted" mine properly. I would often just use them as a steam room for some sun-loving plants—until I decided one day that it was time to get my hands dirty...
A woodland terrarium can be a masterful artifact for the home—and a far more interesting (and long-lasting) centerpiece for the dining room table. The one in my kitchen has been camped out there for months—and really only needs the occasional misting. Terrariums, as I share below, can practically care for themselves, but if made improperly, can lead to utter disaster!
Terrariums don't have their own drainage, like you would have with a planter with a hole in the bottom, so you have to create a drainage layer so your plant's roots aren't sitting in water. Woodland terrariums, like the one I'm making, enjoy moist environments, but still can't tolerate swampy conditions, particularly if you're heavy-handed with the watering can. One way around this is by adding a generous layer of stone and activated charcoal underneath a soil layer. Additionally you can use a cardboard egg carton, as I demonstrate here, to add some additional air flow below while still having a moisture-wicking container for the plants in the carton.
I might have went overboard with the amount of plants for this particular terrarium (you mean I bought too many plants??? hehehe) but I generally LOVE having more plants than I need because you'll want to have options when it comes to your terrarium.
In addition to the plants, I also had some gorgeous driftwood, one of which I selected to go into this terrarium. Later down the line, I collected some grapevines from Pennsylvania to add to my terrarium and even strategically place a Tillandsia (air plant) in there.
To make sure you're not too heavy-handed with the watering, I would say invest in a plant mister. What I love about these closed containers is that when plants transpire, the moisture really doesn't have anywhere to go, so it essentially "cycles" through the terrarium, creating it's own biosphere. Of course, this may mean that water can build up and fog the glass walls, so if you see that happening, lift up the container to air out, and simply get a dry cloth and clean off the terrarium glass. It'll keep it looking nice and presentable whilst preventing any mold build-up! 🌿
potting soil (type of soil will depend on what you're planting)
small river stones, hydro stones or lava stones
activated horticultural charcoal
plants of choice (I used golden clubmoss, moss, and ferns)
cardboard egg carton (optional)
decorative wood, stones, vines, etc. (optional)
Take note to how deep your terrarium basin is. If it's shallow, like mine was (~ 2"), then just note that you'll likely be planting smaller plants since you'll need adequate drainage, which will be created by the stone layer.
Place a layer of stone on the base of the terrarium. I could only muster around 3/4" inch or less of stone in my terrarium, since it's a shallow basin.
Next add a thin layer of charcoal. This helps reduce any bacterial buildup in the soil and around the roots of the plant.
If you're going to use an egg carton, then I would add it to the terrarium now. The benefit of the egg carton is as follows: The "pockets" underneath the carton creates good air flow, and if you ever overwater the terrarium, the plant roots will be "saved" from the swamp. Plus the egg carton acts as a moisture-wicking layer. This is particularly valuable for plants like orchids. Additionally, I like how the egg carton can create a natural "terrain" within the terrarium.
Begin to plot out where you want your plants in the terrarium and other features, like stones and wood. I typically like to sketch a layout in advance, but I improvised this one.
Place some soil in the terrarium and begin planting your plants, making sure that they are firmly planted in the correct potting soil. Because I am doing a woodland terrarium, I went with a potting soil, peat moss mix.
Do any additional touches to the terrarium.
Spray the terrarium generously with a mister.
Place top on, taking care not to crush any leaves of plants that may be peeking out of the edges.
Place your woodland terrarium in an area that isn't directly up against any sunny windows. Too much sun will cook or burn the plants, as the glass acts as a little greenhouse. I have two of my terrariums about 7 feet (2 meters) away from a North-facing window.