How to Build a Terrarium: Tips, Tricks & the Basics

So, you’ve found a beautiful glass terrarium and you’re itching to fill it with plants. You’ve googled ‘how to build a terrarium’, but the reams of info online has left you scratching your head. Where to start? Are all the steps necessary? Do I need special soil? How often should I water my terrarium? You’ve watched a few videos, but really, you’re just keen to get your new accessory on display and pronto. After successfully keeping my terrarium alive for a good few months now, I thought I’d share some terrarium tips for the impatient indoor gardener.

How to build a terrarium

How to Build a Terrarium the Easy Way


The Bare Essentials for Open Terrarium Building and Care:

  • an open glass receptacle
  • mini cacti and succulents
  • small stones or pebbles (extra if you want to cover the top for a ‘decorative’ look)
  • houseplant compost
  • tweezers or kitchen towel
  • a spray bottle/plant mister


  1. Choose your receptacle – a glass terrarium with an opening works well for cacti and succulents by encouraging air flow and reducing moisture.
  2. Choose your plants – a mix of succulents and cacti work well together because they need a similar level of water (limited!)
  3. Fill the base of your terrarium with a layer of small pebbles or stones. This is really important to create drainage and ensure the roots of the plants don’t sit in water.
  4. Add a layer of potting compost (many guides say cacti compost, but my house plant compost has worked just fine).
  5. Mentally envisage where each plant will fit in the terrarium – prickly cacti are hard to maneuver, especially in small spaces! Use kitchen towel or long tweezers to gently move the plants into position. Avoid placing any plants too close to the glass edges so they have space to grow.
  6. Fill in the gaps around the plants with more soil and push down lightly to pack the plants into place.
  7. Mist the terrarium lightly.
  8. Sprinkle some more decorative stones or pebbles on the top of the soil to finish the look.

Terrarium FAQs: Oliver Bonas terrarium with succulents and cacti

Terrarium Building FAQs

How often should you water your terrarium?

If your terrarium is made of cacti and succulents, mist it with a spray bottle every 10-14 days or so. But, only if the soil looks and feels dry. Cacti and succulents won’t survive if you drown them! They’re more likely to survive if you forget about them for a while, rather than over-doing the watering.

Does a terrarium need direct sunlight?

Terrariums should be placed in a sunny location but not in direct sunlight. They are essentially mini greenhouses – too much sun and you’ll cook your plants!

Do you have to use activated charcoal in a terrarium?

Not really. Activated charcoal is a useful drainage layer to pull out excess moisture from the soil. It ensures your plants’ roots aren’t sitting in water. Having said that, if you don’t have any to hand, a good drainage layer of pebbles or stones will be fine for cacti and succulents (as long as you aren’t over-watering!)

Where should I place my terrarium?

Avoid direct sunlight, but the location should be sunny. Avoid placing your terrarium near a radiator or underfloor heating, again, this can ‘cook’ the plants and dry them out very quickly.

Potting soil, cacti and succulent plants for terrariums

There’s a lot of information out there if you’re looking to create a closed terrarium which acts like its own ecosystem. For serial plant killers, the open variety using cacti and succulents (above)  is a much easier version to look after. Just remember, mist, don’t water!

How did your turn out?

with love, b.xo



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