Terrariums: your guide to caring for these miniature gardens

Terrariums are delightful miniature gardens that are grown in open or closed glass containers. Even the smallest apartments have room for a terrarium!

Quite easy to maintain, terrariums are calming to look at and you can “garden” in your terrarium whatever the weather and at any time of the day or night.

Old fish tanks, vintage vases and recycled coffee jars can all create fantastic terrariums and there are also special bowls, pyramids, spheres, cloches and bell jars available for sale that can be used as very Insta-worthy terrariums.

First things first, position your terrarium in a brightly lit position that isn’t in direct light, as direct sun could burn the plants inside or make the terrarium too hot.

Plants that are perfect for terrariums include spider plants, dwarf parlour palms, leafy hare’s foot and maidenhair ferns, English ivy, soft green mosses and colourful nerve plants (Fittonia spp). Choose the type and number of terrarium plants based on the size of your container. A range of taller, medium sized and low growing plants can help create a fabulous mini forest effect. Plants that love growing in moist, rainforest or tropical climates are great for growing in the protected, humid environment created by terrariums. Garden centres will often stock of range of small terrarium-friendly plants, as well as the pebbles, sphagnum moss and potting mix you’ll need to fill your terrarium. Second hand stores can be a great place to find interesting glass containers that make perfect terrariums.

Terrariums can also be enjoyable and engaging for kids to help create and then decorate with their favourite miniature plastic toys and figurines. Tiny fairies and mini magical creatures are right at home in a terrarium, as is pint sized fairy garden furniture. Small dinosaurs hidden in amongst a Jurassic style themed terrarium are also a fun idea.

Here are the simple steps to creating your own terrarium:

  1. Place a 2cm layer of pebbles or stones in the base of the container. With terrariums not having drainage holes, the pebbles help to improve the drainage.
  2. Next, spread a 2cm layer is sphagnum moss over the pebbles. Sphagnum moss (available in bags in garden centres) creates a moisture absorbent layer over the pebbles.
  3. Mix some horticultural charcoal (also available in garden centres) into premium potting mix (add one handful of charcoal to nine handfuls of potting mix) and then gently scoop this mix into the terrarium, on top of the sphagnum moss. Charcoal helps to purify the mix and reduce odours. The depth of the potting mix should be matched to the size of the root systems of your terrarium plants, so it’s just deep enough to cover all the roots.
  4. Make small holes in the potting mix, remove the terrarium plants from their containers and place your plants into the holes, giving each plant enough to grow. Backfill with potting mix so all the roots are covered.
  5. Gently apply a small amount of water over the terrarium to settle the potting mix around the plants roots.
  6. At this stage you may want to add decorative items such as shells, pebbles, sand or rocks around the plants, or place sections of moss over the mix.
  7. Clean down the insides of the glass container with paper towel. A clean terrarium looks so much nicer!

To keep your terrarium moist, it can be misted with water. Misting is preferable to watering, as it reduces the chances of overwatering. Don’t let water accumulate in the bottom layer of pebbles, as this can lead to root rot. You’ll be able to see any pooled moisture through the glass. Closed terrariums will only require an occasional misting, as they’ll retain most of the moisture within the container.

Small and narrow tools for digging and plant placement are handy when it comes to creating a terrarium, as is a funnel for spreading tiny pebbles or sand and a pair of tongs for placing decorations. Narrow mouthed containers can be tricky to manoeuvre in, so when you’re starting out, choose a terrarium with a wide opening.

Cacti and succulents can also be grown in terrariums, however special care is required. To create a drier, more airy environment the terrarium should be open (not sealed), positioned in a very brightly lit spot and a specialty cacti and succulent potting mix used (which is gritty and free draining). Choose succulents that will tolerate growing indoors, such as jade plants and zebra cactus (Haworthia sp). It’s very important not to overwater terrariums with cacti and succulents, as they detest wet feet and can be prone to root rot.

To keep your terrarium healthy and looking great, regularly remove any dead or yellow leaves, trim back plants that are becoming too large or overgrowing other plants and feed a few times a year with a quarter-strength liquid fertiliser.

For more information

Yates Top 50 Indoor Plants and How NOT to Kill Them

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