How to Choose a Terrarium Container: Size, Lid and Glass

Choose the plants before the jar. For a closed tropical terrarium, look for a transparent container with a lid, enough height for future growth and an opening you can work through. A large vessel is usually easier for beginners to balance than a tiny one.

What type of jar works best?

Clear glass jars, large storage jars and purpose-made terrariums can all work. Clean reused glass is a practical budget option. Avoid chipped rims, unstable bases and containers you cannot clean or reach into safely.

How big should a terrarium container be?

Measure the plant’s root ball and expected growth rather than choosing by appearance. For a first project, a reasonably wide and tall jar gives room to add soil, trim plants and manage condensation. The RHS notes that containers around 30 cm wide and tall can be practical, though smaller projects are possible.

Should the lid be airtight?

For a closed terrarium, a well-fitting lid helps retain humidity. A loosely fitted lid exchanges more air and may require more watering. Transparent lids admit more light than opaque ones; metal lids can rust in consistently humid conditions.

What about narrow-neck bottles?

They can look attractive but make planting, pruning and cleaning more difficult. Long spoons, tongs or chopsticks can help. Beginners who want minimal frustration should start with a wide opening.

Common buying mistakes

• Buying a beautiful miniature jar that cannot accommodate mature plants.
• Choosing tinted or opaque glass that reduces useful light.
• Using a sharp, cracked or unstable container.
• Assuming a lid can solve inappropriate plant or watering choices.

How do I clean a used jar?

Wash thoroughly, remove residues, rinse and allow to dry. Avoid leaving cleaning chemicals where they could harm plant roots. Handle large glass containers carefully.

FAQ

Can I reuse a pickle jar?

Yes, if it is clean, stable, transparent and large enough for your plants.

Can a fish bowl be a closed terrarium?

Only if it has a suitable lid. Without one, it behaves as an open display.

Is plastic acceptable?

Transparent plastic may work, but check stability, scratches, cleaning and how it reacts to light and temperature.

Next step

Compare open and closed systems, then follow the construction guide.

How we researched this

We use the Royal Horticultural Society’s terrarium reference as a starting point. This is a researched educational article, not a claim of original hands-on testing. Plant requirements vary by species and growing conditions.

Explore the Terrarium Learning Hub for related subjects and practical projects.