Updated/Fact-Chacked on February 25, 2022 by John
Making an open terrarium for succulents is relatively easy once you have all the materials needed. The materials required are the same as for a closed terrarium, but the glass container needs to be open.
Open terrariums are much easier to manage than closed terrariums, you don’t have to worry so much about humidity levels killing the plants. Making an open terrarium with succulents is also a great project for children.
Items to make an open terrarium for succulents
All these items can be bought from either Amazon or Etsy. For low-cost glass containers try shops like The Range and B&M.
Glass container – you can buy dedicated open terrarium cases relatively cheaply online or in stores. Glass fish bowls make great open terrariums or buy a dedicated geometric container like below from Etsy.
Gravel/Pebbles – for the base to create a false bottom to hold any excess water
Activated charcoal – this helps purify the water running through and keeps the plant’s roots free from decay
Tropical soil – buy ‘tropical soil’ online or in a local store. If you are considering making a few terrariums, it’s worth making up your own substrate mix. A good mixture for succulents is: 3 parts house potting soil, 2 parts coarse sand and 1 part perlite. Perlite looks like small white stones and is used to stop soil compacting, it’s also lightweight and does not absorb water.
Plants – choose a few succulents with different colours and shapes to provide interest
Decorative stones – to finish off the top layer and make the plants stand out. White decorative stones provide contrast.
Ornaments – anything else you want to finish off the terrarium with like sticks, figures or mosses.
Steps to make an open terrarium for succulents
1. Add your pebbles or gravel into the base of your glass container. This creates a false bottom and stops the soil and plant roots from sitting in water. If you don’t use a false bottom, there is a chance plant roots will rot.
2. Add the activated charcoal on top of the pebbles to cover the surface, it doesn’t have to be a thick layer, but enough to clean any water passing through.
3. Add your tropical soil around 5-8cm deep, enough so the plant roots can be buried completely. You can add more soil after the plants are added. It’s best to plan ahead and sit your plants in the glass container first to see how they look and calculate the soil quantity required – you don’t want the terrarium half full of soil and plants sticking out of the top.
4. With a small implement, dig a small hole in the soil and place your succulents into the space, covering with more soil.
5. Add your decorative stones and any other features to finish it off.
6. Lightly water the succulents to allow them to bed into their new home. You can use a mist spray or a miniature indoor watering can.
7. Place your open terrarium in a sunny location, like a south-facing window sill.
I made this open terrarium below in a fishbowl. The terrarium includes succulents and miniature house plants, driftwood and sea glass from my local beach and ‘see no evil hear no evil’ baby buddha figures – I like adding buddhas to my terrariums! Overall, I think I added too much soil, but it still looks good.
Open terrarium problems and maintenance
Succulents are easy to grow and need very little maintenance. Just make sure the soil does not dry out too much.
Design tips for open terrariums
For terrariums, I always think size matters. The bigger your terrarium (open or closed), the better it will look; you can also add more plants and features as you have more space to work with.
I’m currently making a custom open terrarium to fit a 100cm wide window sill. I’ve spent hours trying to find a large glass container but have had no luck. I’ve now opted for using clear acrylic sheets which I will glue together to create the exact dimensions needed (100 cm long, 20 cm wide and a height of 10cm). I’m just praying the glue will hold all the sides together as it cost me over £60 just for the sheets, I am also going to need a lot of materials. I will update this post with the finished look once it’s complete.
Open Terrarium FAQs
Can succulents live in an open terrarium?
Succulents are perfect in open terrariums, but will not survive long in a closed terrarium due to the high humidity levels.
Do you really need charcoal for a terrarium?
You can make terrariums without activated charcoal, but it will help and make the plants last longer.
What plants are best for an open terrarium?
Any plant that is regarded as a succulent or air plant that thrives in dry conditions.
How often do you water succulents in a terrarium?
Succulents should be watered once every 2 weeks, or every week if you think the soil is drying out during hot summer months.
Can you plant succulents in just rocks?
No, you will need a small amount of soil for the roots to take hold in.
What kind of soil do succulents like?
Succulents need tropical soil or cactus soil which has good drainage. When you buy tropical soil it comes mixed with gravel to allow water to drain through.
How long do succulent terrariums last?
A succulent open terrarium can last for decades in the right conditions.
Can you put an aloe plant in a terrarium?
Yes you can plant aloe vera plants in an open terrarium but it will need to be large. Aloe vera can grow up to 15″ heigh.
Can you plant seeds in a terrarium?
Yes you can plant seeds in an open terrarium, the added humidity will help the seeds germinate.
Also check out our guide to winter-hardy succulents that can be grown outdoors
John Green is a 46-year-old graphic designer living in Durham. John is RHS level 3 certified and owns an allotment in Durham.