How To Make a Terrarium

Terraria (plural of terrarium) are decorative indoor gardens that contain miniature, slow growing plants. Currently terrariums are rather popular, due in part to the fact that they are incredibly low maintenance and really rather satisfying to make and grow.

In this article, we give you a step-by-step guide to creating your own terrarium and give advice on which plants to include.

What Is A Terrarium?

A terrarium container is typically made from glass so that the beauty of the plants and their resulting eco-system can be fully enjoyed. Terrariums come in two types, either sealed or open. A sealed terrarium will have the benefit of a removable lid, whilst the open terrarium has no lid and is exposed to the air.

Which Plants Are Best For A Terrarium?

A good-looking terrarium will have plants of differing height and spread, as well as different coloured foliage, so bear this in mind when choosing your plants. Don’t overcrowd your terrarium, consider the size of your container versus the size of the plant when fully grown, making sure there is enough space for all the plants you plan to plant. Due to the fact that glass filters UV light, a terrarium is suited to more shade-loving plants, such as mini ferns rather than sun-lovers, such as cacti. Plants most suited to terrariums are those from the fern family, miniature orchids, succulents and if your terrarium is open sided then air plants and cacti will also thrive.

Horticulturalist and garden writer, Pumpkin Beth provides a comprehensive list of suitable plants for terrariums here.

Creating Your Terrarium

Step 1 – Source Your Container

The right container to house your terrarium is essential. It needs to be of big enough size for your plants to thrive and grow. TV botanist James Wong, who is a four-time RHS medal winner and expert in indoor gardening, recommends a minimum of 30cm squared. For the shape, your container can be almost any shape, square, round, bottle, jar or hexagonal. Bear in mind that an open container will need to be watered more regularly than a closed one.

Step 2 – Gather Your Tools

Along with your container, you will need:

  • long handled tweezers
  • non-metallic small spade and trowel
  • snippers
  • scoop or funnel for the soil
  • a base layer for drainage, such as tiny clay granules called Hydroleca
  • a good quality multi-purpose house plant compost
  • plants, after reading the advice and list above
  • decorative wood, moss, rocks and dressing stones
  • small watering can and a plant mister

Step 3 – Fill Your Terrarium

Begin by placing a layer of around an inch thick of your drainage material in the bottom and on top of this, around 30mm (3cm) or your good quality house plant soil. James Wong advises not being mean or scrimping on this step – the plants need a good layer in which to take root. Consider design and space when introducing your plants – plants at different heights will allow you to enjoy the beauty of each plant whilst space between will allow them to grow.

James uses matter such as lightweight tufa rocks and miniature spider wood branches to plant at different heights to achieve a 3D look with differing textures. He also advises not leaving any soil bare – cover with different sizes of gravel or moss to complete a truly natural look.

Step 4 – Watering

James advises that an initial thorough soaking of the compost with a small watering will encourage the new plants to bed in. After planting do not water more than once a fortnight. If you see the compost beginning to look dry, add a little water as above. A good spritz of the leaves with a spray bottle every few days is also advisable. Your terrarium should be placed in a reasonably light position, but not in strong direct sunlight.

Other than an occasional water, your terrarium requires little ongoing maintenance, but they will continue to give you joy for months or years (depending on the varieties you planted) to come.