Recently someone in our garden club asked about how you put together a terrarium. Since our house cleaner also recently knocked over and broke the small terrarium we had (sitting on an overly-tippy end table), I took that opportunity to pick up what I’d really wanted all along — a taller, free-standing terrarium, big enough to house full-size orchids (24″ high interior).
A trip to Trader Joe’s for cheap orchids, and some potting soil, little plants, pebbles, and moss from the garden store, and I was ready to go. There’s very little to instruct, really, but here goes, in case it’s helpful:
a) I started with a layer of pebbles in the bottom for drainage, followed by a layer of soil.
b) I added the orchids next, and this bit, I’m not sure I did right, but since I know orchids prefer their roots to stay mostly dry, I left them potted in their little plastic pots filled with orchid bark, and just nestled those in the soil.
c) Then I tucked in some little terrarium-type plants around them. Your nursery can advise you on what’s well suited to this, but just keep in mind that what you’re recreating is essentially a moist, jungly environment. Terrariums are related to Wardian cases, which were used to bring tropical plants back from the tropics to England, keeping them alive on the long voyage. So I wouldn’t use a terrarium for succulents!
d) I added a layer of moss, which serves the dual function of looking nice and also retaining moisture in the soil.
e) That’s it! Put the lid on, and you have a moist, mostly self-contained environment. It should need water rarely. My understanding is that usually terrarium plants want plenty of indirect light (not blasted with sun) — imagine that you’re under the tree cover of a tropical jungle. So I put mine by a window that’s near an overhanging porch roof.
Now, the next step is that eventually, these orchids will lose all their flowers (though it’ll take a few months; I try to pick orchids that are mostly buds, with just a few blooms, so the show is sure to last a long time). In theory, one can then take care of them appropriately so that they’ll come back, year after year. I haven’t actually done that yet, but I have friends that do it regularly, and swear it isn’t hard.
When these are done, I’m hoping to try that, and I’m also hoping to replace one of them with a more interesting variety, since they’re all, I think, pretty standard phalaeonopsis (or moth) orchids, and there are so many more cool varieties out there. I’m looking forward to eventually experimenting with other types.