What You Need to Know About Making a Terrarium
These glass mini gardens are trendier than ever. Keep these basic tips in mind before you create or buy one of your own.
Terrariums aren’t a new concept, but lately it seems like they’re popping up just about everywhere. And with good reason: They’re a low-maintenance, stylish décor statement—plus, they're perfect for people who live in a small space or don’t have an outdoor garden of their own. For terrarium novices (or those in need of a refresher), we asked Mike Stone, founder of MakersKit, which sells DIY and craft kits, and co-author of Terrariums: A Complete Guide, for his best tips for creating and caring for these garden containers.
First things first, you’ll need a vessel for your mini garden. When it comes to choosing your container, you can go the traditional route, with a lidded terrarium, or go with an open container, a more modern choice. “Think about how much space you have inside the container you’ve chosen to work with, and choose your plants accordingly,” says Stone. “Allowing room for growth by choosing smaller plants is a good idea.”
“Always make sure the plants are compatible and that you have the proper soil for the job,” Stone says. He recommends three options of plants for your terrarium: ferns and small plants, succulents and cacti, and air plants. Since these three vary when it comes to soil type, maintenance, and even vessel choice, you won’t want to combine these together. “Only use plants with similar watering and light requirements in the same terrarium,” he says.
Ferns and small exotic plants do well in closed terrariums since it’s easier to control the humidity and temperature—you’ll want to water these often. Air plants, on the other hand, don’t require soil and need a light spray of water once a week or a good 10-minute soaking. You don’t want to keep these in a closed container since they absorb moisture from the air—they are called air plants, after all. Lastly, succulents and cacti are great to pair together since they both require very little water. You should place them in open containers since they need to dry out between watering times.
“Tools like funnels, tongs, spoons, and bamboo sticks all make a world of difference, letting you maneuver and position plants and materials in tight spaces,” Stone says. “Activated charcoal, organic fertilizer spikes, and polymer hydration crystals will give your terrarium the best possible start, and keep your plants thriving for months or even years.” These extras absorb toxins and impurities, give the plants nutrients, and absorb extra water, respectively.
To prep the plants, Stone recommends gently loosening the dirt from the plant’s roots before placing in the soil and also giving them some water to help ease them into the new environment. To start assembling the terrarium, begin with a drainage layer of pebbles or vermiculite layers, then add activated charcoal on top. You can also cover the activate charcoal with mesh fabric to prevent root rot. Then top with soil, polymer hydration crystals (optional), and the plants themselves.
“For cacti and succulents, use a coarse, sandy soil,” he says. “For air plants, don’t use any soil at all, they prefer to stay dry and exposed to as much air as possible so simply placing them on a bed of rocks or driftwood is ideal. For small ferns and tropical plants, a moist potting soil will do just fine.”
Terrariums don’t need around-the-clock care. “A closed container needs very little water, and even open terrariums should be watered sparingly,” Stone says. “There is no drainage hole in the bottom of classic terrariums, making it very easy to overwater and swamp your plants! Pruning should be done as the plant begins to outgrow the container. Be sure to leave large, lower leaves intact so the plant can still photosynthesize.”
Sun exposure depends on the plant, but most don’t need to sit on a perpetually sunny spot. “Closed terrariums in particular are susceptible to overheating due to the greenhouse effect of the glass,” he says. “Keeping them in a room that gets plenty of sunlight but out of direct sun, will keep your terrarium at a happy balance.”
If you want to purchase a DIY Kit, MakersKit is offering Real Simple readers 15 percent off your purchase, with the code REALSIMPLE.