Terrariums are seeing a huge wave of popularity recently, and you can easily find internet galleries packed full of eye-catching setups behind glass. A lot of terrariums feature a sealed design to give you a steamy junglescape, but open terrariums are also extremely popular, especially when you start looking for terrarium plants. Open terrariums are usually easier to maintain than closed ones, as long as you follow a few simple guidelines.
They do require that you water them very carefully and monitor the whole system for moisture. Routine maintenance is also a lot, and you should make a point to prune, replant, remove debris, and keep the interior and glass clean. We’re going to outline the basics with open terrarium care and plants so you get a solid understanding of what you need to start one of your own.
Defining an Open Terrarium
Terrarium may encompass any closed container that has plants that adore moisture, but open terrariums are another option that is quickly catching on. Both versions have pretty mini landscapes, and open terrariums are great for anyone who wants a natural green space but doesn’t necessarily have the time to dedicate to a lot of upkeep.
Open terrariums are fantastic for plants that don’t need humidity to thrive. The glassed-in area gives you aird, bright conditions, so the most practical and common choice for terrarium plants are succulents. However, there are many different types available.
Understanding Terrarium Plants
Terrarium plants are slow-growing, small plants that grow well in a glass vessel. If you’re not very good at taking care of common houseplants, they’re a great shortcut to help surround your space with greenery. Terrariums can make your indoor spaces more inviting and lively, and they’re very versatile when it comes to the size. It’s possible to stay minimalistic or go big with them. A few ideas to help you get started with this project include:
- Add decorative pieces like glass pebbles, seashells, and driftwood to spice up your plant’s world
- Create eye-catching mini landscapes that range from a tropical jungle or desert to a mossy woodland or fairy garden
- Grow carnivorous plants, ferns, succulents, and air plants in your terrarium. They do well in enclosed, small spaces.
- Use several glass vessels like open globes, cloche, jars, and bulbs
Why People Create Open Terrariums
There is a very good reason why open terrariums are popular. First, they’re a fantastic way to get started if you’re new to terrariums. You will still deal with everything that goes into building your terrarium and picking out your terrarium plants, but you don’t have to worry about several factors that can kill a terrarium that are present in closed designs.
In turn, this makes terrariums more versatile when it comes to your home decor. Geometric succulent terrariums and hanging air plant terrariums are also on the rise, and they’re usually more ornamental than horticultural, but they have several benefits attached to them. They include:
- Better airflow for your terrarium plants
- Lower risk of rot or mold
- More forgiving
- No issues with condensation
Finding the Best Open Terrarium Plants
As a general rule, the best terrarium plants you can source are slow-growing and on the small side. You don’t want them to touch the sides of your container. Open terrariums are perfect for plants that prefer dry conditions, including air plants, succulents, and cacti. We’ve rounded up the best terrarium plants for open designs below.
Agave is a varied succulent that adds both texture and volume to your terrarium. This terrarium plant is usually hardy, slow-growing, and it adores the sun. Even though a lot of agaves are landscaping plants, you can find pretty mini varieties that can live for years happily in an open terrarium before they outgrow it. The Victoriae reginae is a prized dwarf agave terrarium plant.
2. Air Plants (Tillandsia)
Air plants don’t require soil to do well. Instead, they attach themselves to a host to survive and absorb water and nutrients using their leaves. This terrarium plant makes a stunning addition to your setup, and they can also work to purify the air. You can put your air plant on top of driftwood or set up a flat stone as the base.
No matter if you choose to put it by itself in a minimalist container or arrange it with like-succulents in a bigger vessel, aloe is a hardy terrarium plant. It offers very long leaves with jagged edges in a pretty green-gray coloring, and it gives you a very unique cactus-like appearance.
Direct sunlight can easily burn or scorch the tender leaves on this terrarium plant, so the setup should be in a space where it gets a lot of indirect light. You should plant it in fast-draining succulent or cacti soil, and remember the rule of drenches between droughts watering. So, you’ll water it infrequently but thoroughly.
4. Ball Cactus (Parodia)
The Parodia genus has several squat, easy-to-grow, small cacti that work well as a terrarium plant in an open setup. The spines on these plants are showy and unusual. They usually don’t do well with intense sunlight, and they usually want more shade than other succulents. Parodia leninghausiii and Parodia haselbergii are two good varieties to consider.
5. Burro’s Tail
Offering sweeping, long stems that get covered in overlapping, plump leaves, this indoor vine plant is a nice addition as a terrarium plant. Like any other succulent, this one tolerates dry air and heat very well, and it only needs very sparing water sessions.
You should put your terrarium on a sunny west or south-facing windowsill if you want to add this plant because it requires a few indirect hours of sun each day. You can mix this with other plants, but you need to leave plenty of room around it to allow the plant to grow. Also, handle it as delicately as you can because it’s very fragile.
6. Button Ferns
Not only is the button fern a great small pot plant, but it’s a wonderful terrarium plant. They’re highly tolerant to drought, and they have an evergreen nature with leathery, round foliage. They like to be in subdued lighting conditions during the summer months and indirect but bright light during the winter.
If you’re trying to create a desert landscape with your open terrarium, add cacti. This is one terrarium plant that can’t grow well in closed terrariums with bad airflow and higher humidity levels. You’ll need a large or medium-sized open container for it. They look stunning, but they won’t survive very long due to the fact that they need low humidity and regular airflow to do well.
8. Dwarf Sansevieria
This is a much smaller cousin to the popular snake plant, and it’s very easy to care for. This terrarium plant won’t get much higher than six inches, and it offers variegated, straplike foliage that contrasts nicely to more squat, blockier succulent plants. It will do well under a range of indirect but bright light, but it’ll lose striping in dim lighting. You want to water it sparingly and it’s very slow-growing.
This Central American terrarium plant is part of the succulent family, and it offers rosette-style leaves that grow into a flower shape. They like tight conditions, and echeveria has countless variations you can choose from, ranging from variegated cultivars to the purple leafed Neon Breaker. It produces flowers on stalks during the late summer months.
This category encompasses a very big family of eccentric, small succulents. They need slightly more water than most succulents, but they won’t do well in wet conditions. So, you have to be very careful when you water them. They also won’t tolerate direct sunlight, and they’re very slow-growing. Haworthia will add texture to your terrarium.
11. Hen and Chicks
Also known as house leaks, this terrarium plant has foliage that gets green, red, and copper or a mixture of different colors. Hen and Chicks is the perfect lower-maintenance plant to add to your open terrarium. They grow rosette clusters, and the parent rosette is called the “hen” while the smaller ones are called the “chicks”.
Hypoestes, better known as the common name of the polka dot plant, offers speckled, vibrant leaves that can have colors ranging from bright red to light pink. They have variegated designs with green edges. You’ll need good drainage with rich soil, like a peat-based one for this plant to thrive. This terrarium plant should get a lot of filtered, bright sunlight. You should only water when the top ½ inch of soil dries out.
This evergreen terrarium plant is very commonly used because it needs very little sunlight and water to thrive. The glossy, smooth leaves in a rich forest-green color are very eye-catching, and it looks like a tiny tree. Jade plants like succulent-specific potting soil with a lot of indirect but bright sunlight. Direct sunlight will scorch the leaves. You only water this plant every two or three weeks, except during sunnier and warmer months when you can increase this to once a week.
Kalanchoe is a free-flowering plant family that offers a huge amount of variety, and smaller cultivars function very well as terrarium plants. However, most of them will eventually outgrow the space, but they are very slow-growing indoors. They will add months of interest and color to the terrarium landscape, and the Paddle Plant is a very popular choice.
Lithops have the nickname of the living stones, and they’re a very small and unique permanent terrarium plant. They look very similar to the Split Rock Plant, and they’re fascinating succulents that have a reputation for being difficult. This stems from the fact that they rot easily and need very little water. They are well placed in direct sunlight, and watering them roughly five times a year is usually enough. Never water your lithops during the winter months.
This ball and cylindrical-shaped terrarium plant is a miniature of the spiny cactus. Mammillaria is a family that offers several compact varieties that do well in an open terrarium, including Snowball, Powder Puff, Old Lady, and Pinchion cacti. They’re all easy to care for, and they need a lot of light with very little water. They flower during the spring months and slow down in the winter.
17. Mother of Pearl or Ghost Plant
This low-maintenance plant is a succulent with grayish-pink coloring, and it’s a nice choice for your open terrarium. It grows well under bright sunshine, and the amount of shade or sunlight it gets will dictate which color it turns. It’s enough to water them every other week to keep them healthy.
18. Ox Tongue Gasteria
Not only does this plant help purify the air, but it’s a very easy-going succulent that comes in a huge range of sizes down to a dwarf variety that only gets four inches tall. It has strap-like leaves that have a rougher texture. It thrives when you place it in indirect but bright light, and it can handle dimmer lighting than many terrarium plants. They need very little water as they’re slow growers.
Many people call pothos the cubicle plant, and for good reason. It can grow just about everywhere, and it’s virtually an indestructible terrarium plant. As a bonus, the vines are very pretty when you allow them to trail out of your open terrarium. They like bright to medium indirect lighting, but they can tolerate lower light. When it comes to soil, the plant isn’t too fussy. You should try to get a well-draining, nutrient-rich mix. Allow the soil to dry out slightly between watering sessions.
There are several varieties of terrarium plants in this barrel or button-shaped plant family. They flower easily, and rebutia are very easy to grow. They put out flowers during the summer that can be bigger than the plant itself. They like strong light but can tolerate less, and they like cooler temperatures during the night.
21. Sand Rose
This hardy succulent is a terrarium plant that offers fleshy leaves that have green centers and purple or pastel pink-tinged edges. They top out at four inches tall and grow very slowly, and they like indirect light and infrequent watering. The lighting will bring out the plant’s pretty coloring.
Sedum is a varied family that is so forgiving of poor soil and so hard that it goes by the nickname of Stonecrop. They grow faster when you place them in full sun, but they can tolerate less sunshine too. It’s a very friendly plant for beginners.
Sempervivum is a varied member of the Crassula family, and this family also includes Sedum, Jade, and Echeveria. It’s a red-leafed plant that will die after it flowers. It will grow in very tight clumps with rosette-shaped fleshy leaves. As a bonus, this plant can take on different shapes depending on the time of the year, so you get year-round interest with it in your terrarium.
24. Snake Plant
The Snake Plant is on the top of NASA’s Clean Air Study, and it’s a succulent that does well with lower light. This terrarium plant is low-maintenance, and it’s happiest when you put it in medium to bright indirect light with water every two to three weeks. This plant is prone to having issues with root rot, so it does best when you put it in a chunky potting mix that has sand and perlite added in to encourage drainage.
25. Tiger’s Jaw
The descriptive name for this terrarium plant refers to the sharp row of spines that grow along the edges of paired triangular leaves. It’s a very low-growing succulent that won’t outgrow your terrarium quickly. They love heat, and if you give them a strong light source, they can bloom during the fall months. You can pick from a host of hybrids too.
Maintaining An Open Terrarium
Once you have your plants and your open terrarium set up, you have to get a plan in place to maintain it. It’s not a maintenance-free option, but it’s generally more low-maintenance than a closed terrarium.
Small succulents in terrariums don’t need a lot of fertilizer to be happy. You don’t want to encourage them to grow quickly either. The only time you’ll add fertilizer to your terrarium is if they’ve been in the setup for several months or if the growing medium is infertile. Some growers suggest that you do a light feeding once or twice a year, but this is up to your judgment. When you feed your plants, you want to dilute your fertilizer to ¼ of the normal strength and apply it during a watering session. Organic fertilizers are gentle and work well to boost the soil health.
Regular parts of taking care of your open terrarium include transplanting, pruning, and removing debris. This is usually a very easy job since succulents don’t grow very quickly. You should relocate any plants that touch the glass or get up into another plant’s space or lighting area. Overgrowth is sneaky, and this is why you want a landscape plan when you start your terrarium. You should remove dead leaves and other debris to prevent decay and get rid of hiding spots for bugs.
Your terrarium plants will grow at various rates, so you won’t have to prune everything at one time. You should regularly check your terrarium and make adjustments as needed. Replanting is another important aspect as some succulents will languish until they die, and offsets can overwhelm your terrarium. You shouldn’t hesitate to remove overgrown plants.
Proper lighting is important to keep all of your succulents healthy. Even those plants that need indirect light tend to want a lot of it. A north-facing window won’t give you enough sun, but southern windows offer longer, brighter hours that are much better for your open terrarium. West and east-facing windows can work well for lower-light succulents. Even if you have succulents that do well in direct sun, you should pay attention to the interior temperature of the terrarium. Mini succulents are less hardy than mature ones, and heat-lovers can burn if the leaves rest against the hot glass.
The sun’s position also changes with the season, and a suitable spot one month can get too shady or bright in another. Watch for color loss or legginess that indicates that the lighting is off. Give your terrarium a quarter turn every two weeks to ensure your plants don’t start growing lopsided.
Since open terrariums are exposed to the environment, they are more prone to developing problems with pests, bugs, or infestations. Gnats and mealy bugs have been huge issues for terrarium plants, so you have to be very careful on this front. If you see your plants start to rapidly decline, this is a big indicator that you have a pest problem. Give your plants a good, hard look, try to look and see which bugs are causing the issue, and treat your terrarium accordingly.
Watering is infrequent, so it’s easy. The timing does require very careful observation though. Too much moisture can prompt root rot, but dry plants will stop growing and eventually shrivel up. Most terrariums have no drainage holes, and a bottle pebble layer is not adequate for a substitute.
The watering method of soaking the soil only works if you have good drainage. Without any drainage holes, the lower soil will stay wet, and soggy roots will quickly kill a succulent. To water correctly, the following tips can help:
- Instead of watering on a schedule, make a point to check the soil.
- Moderation is critical, and think in teaspoons instead of cups.
- Pick terrarium plants with similar water needs. A lot of succulents like the soil to dry out completely between watering sessions.
- Water less during any dormant seasons.
- Water the base of the plant and avoid splashing the foliage. A lot of people use an eyedropper or a spray bottle over a watering can.
Cleaning An Open Terrarium
Using a tissue or paper towel, regularly dust your plant’s leaves. Remove any stones that have debris and other hardscapes and rinse them. Allow them to air dry before you replace anything. Keep the glass clean to allow the light to shine through. Wipe out the interior with distilled water, but you can use chemicals for the outer glass.
Open Terrarium Planting Tips
There are a few things you can do when you’re planting your open terrarium to get it off to a solid start and help ward off any huge issues.
- Don’t put everything very tightly in the final design as the plants need room to grow and spread out.
- Filtered or distilled water is good if you don’t have drainage in your terrarium. Residual chemicals and salts can stay in the soil once the water evaporates, and it can build up and be toxic to the roots.
- Quarantine new terrarium plants for a few weeks before you add them. It’s harder to treat diseases and pests once they enter the ecosystem.
- Rinse your plants very well before you plant them to reduce the chance of pests getting in.
- Select firm, healthy, chubby succulents without any blemishes or nicks. You want to avoid leggy plants.
- Sterilize your tools before you prune anything, and use a sharp blade. Bruised stems or foliage will invite decay.
- When you add terrarium plants, look for a mix of small and large species.
You now know several pretty and interesting terrarium plants that you can add to your own open terrarium. With a little care and patience, you can easily set up dozens of landscapes that are all self-contained and add a touch of brightness to your room.
Jen is a master gardener, interior designer and home improvement expert. She has completed many home improvement, decor and remodeling projects with her family over the past 10 years on their 4,500 sf Victorian house. She is also a passionate farmer who keeps goats, chickens, turkeys cows and pigs on her farm, and an instructor for her community’s Organic and Sustainable Farming project.