Complete Terrarium Making Guide — Closed vs Open Types

Terrariums recreate miniature natural worlds inside glass containers. Beautiful as interior decor and space-efficient, they have grown increasingly popular in recent years. This article covers everything from terrarium basics to construction steps and long-term care tips. Accessible content even for beginners.

Types and Characteristics of Terrariums

Terrariums fall into two main categories: "closed" and "open." Understanding their characteristics helps you choose the right type for your lifestyle.

• Closed terrariums: Made in lidded glass containers. A self-sustaining water cycle of evaporation and condensation forms inside, making watering virtually unnecessary. Ideal for moisture-loving mosses and tropical plants. Requires the least maintenance
• Open terrariums: Made in lidless glass containers. Good ventilation makes them suitable for plants preferring drier conditions, such as succulents and air plants. Requires regular watering, but lower risk of mold from excess moisture
• Semi-closed terrariums: Made with a partially open lid or narrow-mouthed container. Achieves humidity levels between closed and open types. Suitable for ferns and fittonia that prefer moderate humidity

Choosing a Container

The container choice significantly impacts the terrarium's appearance.

• Glass bottles (closed type): Bottles with cork or glass lids. Mason jars or laboratory bottles from variety stores work too. Wider openings make planting easier
• Glass domes (closed type): A glass dome placed over a wooden or cork base. Highly decorative and display-oriented
• Glass bowls/glasses (open type): Wide-mouthed containers like wine glasses or fish bowls. Easy to work with and beginner-friendly
• Geometric terrariums (open type): Modern designs with glass set in brass or black frames. Eye-catching interior accents
• Selection tips: Choose highly transparent glass. Plastic tends to cloud and is unsuitable for long-term use. Containers at least 15 cm in diameter are easier to work with and look better

Preparing the Base and Substrate

The foundation layers consider both drainage and aesthetics.

• Layer 1 - Drainage (1-2 cm): Lay hydroball or small pumice. Since terrariums have no drainage holes, this layer provides an escape for excess water
• Layer 2 - Activated charcoal (thin layer): A thin layer of charcoal purifies water and prevents odors. Granular horticultural charcoal is easy to use
• Layer 3 - Moss or mesh barrier (thin layer): Prevents soil from falling into the drainage layer. Use thin dried sphagnum moss or cut pot-bottom mesh
• Layer 4 - Substrate (2-4 cm): Black soil-type substrate for moss terrariums; peat moss-based light soil for foliage plants; sand-heavy, well-draining mix for succulents
• Decorative sand or pebbles: White sand or colored gravel adds beautiful finishing touches

Recommended Plants for Terrariums

Plant selection tailored to the container type is key to success.

Recommended for closed terrariums:

• Shinobugoke and Hosobaokinagoke moss: Terrarium classics. Create a beautiful green carpet. Thrive in high humidity, perfect for closed types
• Fittonia: Small plants with beautiful white or red veining. Love humidity and pair perfectly with terrariums
• Selaginella (spike moss): Delicate, fern-like foliage. Grows beautifully in high-humidity environments
• Mini foliage plants (Mini Monstera, Pumila, etc.): Compact varieties that stay manageable inside enclosed containers

Recommended for open terrariums:

• Succulents (Echeveria, Sedum, etc.): Prefer dry conditions, ideal for open types. Colorful combinations create vibrant displays
• Air plants (Tillandsia): No soil needed; mount on stones or driftwood. Prefer well-ventilated environments
• Mini cacti: Small cacti make great accents. Use well-draining sandy substrate

Layout Tips

Maximize your terrarium's visual appeal with these layout pointers.

• Create depth: Place taller plants in back, shorter ones in front. Add rocks or driftwood to create elevation, generating three-dimensional interest
• Use triangular composition: Position the main element off-center to one side, creating a triangular silhouette. This produces a more dynamic impression than centering
• Use stones and driftwood: Lava rock or Seiryu stone for rock formations. Small driftwood creates a sense of scale, suggesting ancient fallen trees
• Leave breathing room: Avoid overcrowding with plants. Showing areas of "bare gravel" or "spreading moss" enhances overall beauty
• Figurines and accessories: Small animal figurines or miniature houses add narrative charm. But too many have the opposite effect

Long-Term Care

Keep your terrarium beautiful with these maintenance practices.

• Watering closed types: Generally unnecessary. When condensation on the inner glass disappears, mist lightly with a spray bottle. Over-watering causes root rot and mold
• Watering open types: Mist when the soil surface dries. With no drainage holes, apply water sparingly. Avoid letting water pool at the bottom
• Placement: Avoid direct sunlight (glass interior overheats and steams plants). Bright indirect light or filtered light through a sheer curtain is ideal
• If mold appears: Remove carefully with a cotton swab and open the lid for ventilation. Recurring mold signals excessive moisture
• Overgrown plants: Trim with small scissors. Remove clippings to prevent decay
• Fogged glass: Wipe interior droplets with a paper-towel-wrapped stick. Clean the exterior regularly with glass cleaner

Find Terrarium Plants on BriChoku

Terrariums are a fascinating hobby that lets you create your own world in a small container. Follow the basic steps and even beginners can craft beautiful pieces. On BriChoku, you can purchase quality moss, mini foliage, and other terrarium-suitable plants directly from trusted growers. With quality materials, create a one-of-a-kind terrarium.