How to choose the right terrarium
Updated June 2026Independently researchedNo paid placement.
A terrarium is a self-contained miniature garden, and the best one for you depends on your space, light, and the plants you want to grow. For beginners, a closed glass terrarium with good drainage and a tight-fitting lid is a forgiving choice. Focus on quality glass, a wide opening for access, and a sturdy base.
What kind of terrarium is right for you?
The first big decision is open versus closed. Open terrariums are shallow dishes or bowls without a lid; they suit succulents and cacti that prefer dry air. Closed terrariums have a glass or cork lid and create a humid, tropical environment perfect for ferns, mosses, and small orchids. If you’re new to terrariums, a closed one is more forgiving because it waters itself through condensation, but you must monitor for mold. Your choice also depends on available natural light. Closed terrariums need bright, indirect sun – a north- or east-facing window works well. Open terrariums can handle a bit more direct light, but they’ll need more frequent watering. Think about how much maintenance you want: closed types require less water but more occasional pruning, while open ones need regular misting and soil checks.
How to choose the right size and shape
Terrariums come in every size from a tiny apothecary jar to a tabletop bell jar. The size you pick should match the space you have and the plants you want. A very small container (under 6 inches in diameter) limits your plant choices to tiny ferns or moss and can overheat in direct light. Beside the footprint, consider height: tall, narrow jars allow vertical layering with tall plants, while wide, shallow bowls are better for sprawling succulents. Your best bet for a first terrarium is a medium-sized container with a wide opening – roughly 8 to 12 inches across. A wide mouth makes planting, layering soil, and cleaning much easier than a narrow-necked bottle. Avoid shapes that are too tall or too shallow unless you have a specific plant in mind. The container should also feel balanced: a heavy base prevents tipping, which is especially important for top-heavy arrangements.
Glass versus acrylic: which is better?
Glass is the traditional and most popular material for terrariums. It’s crystal clear, doesn’t scratch easily, and doesn’t yellow over time. It’s also heavier, which can be a plus for stability. Acrylic (or plastic) is lighter and shatter-resistant, making it a practical choice for homes with kids or pets, or for hanging terrariums. However, acrylic scratches easily – even wiping with a rough cloth can leave marks – and it can become cloudy after a few years. For purely aesthetic displays that you plan to keep for years, clear glass is the winner. If you need something portable or safer, a high-quality acrylic terrarium can work, but accept that it won’t stay perfectly pristine. Also check the clarity: some acrylic terrariums have a slight blue tint or distort the view. Always read owner reviews about scratching and clarity before buying.
Understanding drainage and layering
A proper drainage layer is the single most important factor for a healthy terrarium. Most quality terrarium containers include a false bottom or are sold with a drainage tray, but if you buy a simple glass bowl without one, you’ll need to add a layer of pebbles, activated charcoal, and coarse sand before the soil. This keeps plant roots from sitting in water and prevents rot. When shopping, look for a container that either comes with a built-in drainage layer (some have a separate tray underneath) or is deep enough to allow you to add one yourself. A terrarium without any drainage is a recipe for failure unless you water extremely sparingly. Also consider a container with a tight-fitting lid for closed setups – the lid helps maintain humidity and reduces the need for watering. If the lid doesn’t seal well, you’ll have to mist more often.
Best plants for your terrarium
The plants you choose determine the rest of your setup. For a closed, humid terrarium, stick with moisture-lovers like ferns, peperomias, pileas, mosses, and small orchids. These plants thrive in indirect light and high humidity. Succulents and cacti belong in open, dry terrariums with plenty of direct light and a free-draining soil mix. Avoid mixing desert and tropical plants in the same container – they have completely opposite water and light needs. Also avoid fast-growing plants like mint or most vines; they’ll quickly outgrow the terrarium and become a tangled mess. Starter plants should be small, slow-growing, and easy to trim. Some great choices are button fern, nerve plant (fittonia), and various mosses. For open terrariums, try haworthia, echeveria, and lithops. Always buy from a reputable nursery to avoid introducing pests or diseases.
How to maintain your terrarium long-term
Maintenance is primarily about balancing light and water. A closed terrarium that looks foggy inside for more than a few hours each day is too wet – remove the lid for a day to let it dry out. If the soil feels dry and the plants look wilted, give it a gentle misting. Open terrariums dry out faster, so check the soil every few days. Pruning is also necessary. Trim yellow or overgrown leaves as soon as you see them to prevent rot. Clean the glass walls with a soft cloth and distilled water to avoid mineral spots. Every six to twelve months, refresh the top layer of soil or replace a plant that has outgrown its home. And always keep your terrarium out of direct, hot sun – that can cook the plants inside. With these simple habits, a well-built terrarium can thrive for years with very little intervention.
Frequently asked questions
Can I use any glass jar as a terrarium?
Yes, as long as you can add a drainage layer and access the inside easily. A mason jar works for tiny terrariums, but a wide-mouthed jar or a cookie jar with a lid is much easier to plant and maintain.
How often do I water a closed terrarium?
Most closed terrariums only need watering every two to four weeks. Watch for condensation on the glass – if it’s heavy and persistent, hold off. If the glass is clear and the soil feels dry, a light misting is enough.
Do I need special soil for a terrarium?
Yes. Regular potting soil is too dense and holds too much moisture, which leads to root rot. Use a lightweight, well-draining mix – typically a blend of peat, perlite, and sand. Many garden centers sell pre-mixed terrarium soil.
Can I keep a terrarium in a room with no natural light?
Terrariums need some light, but a few hours of indirect natural light per day is usually enough. If you have no windows, a grow light on a timer for 10 to 12 hours a day can work, but it’s not ideal for reaching the lush look of a naturally lit setup.
How do I prevent mold and fungus in a closed terrarium?
Good airflow and proper drainage are key. Leave the lid off for a few hours each week, use a layer of activated charcoal between the drainage and soil, and remove any dead leaves quickly. If mold appears, spot-clean with hydrogen peroxide and reduce moisture.
Do terrariums need fertilizer?
Very little. Most terrarium plants grow slowly and do fine with the nutrients in their soil for the first year. After that, you can add a tiny amount of liquid houseplant fertilizer diluted to half-strength once in spring and once in summer – overfeeding promotes weak, leggy growth.