Gardening expert reveals why you should never grow cacti in a terrarium

We've all seen so many beautiful terrarium arrangements with cacti and succulents online, that it can seem as if placing these plants in a terrarium is the house plant care they require. However, this is completely wrong, according to house plant experts. Not only will your cactus not do well in a terrarium, it might actually die.  

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The reason for this, in a nutshell, is this: cacti are desert plants that like to stay dry most of the time, good drainage, and cold nighttime temperatures. This is the exact opposite of the environment that terrariums provide: humid, with poor airflow, poor
(or no) drainage, and a mini-greenhouse effect. 

Gardening presenter James Wong has even called cacti terrariums his 'biggest pet peeve' in a recent Guardian (opens in new tab) article. 'The easiest way to kill one of these hard-to-kill plants is to put it in a terrarium', he wrote. 

So, keep your terrariums for your steam-loving mini jungle plants and plant your cacti in pots, positioning them on a bright windowsill. The same actually goes for all succulents, although some succulent varieties will tolerate a very open terrarium design where they'll get plenty of light and air circulation. 

If you really can't resist the gorgeous look of a terrarium with cacti and succulents the Cacti experts from Cactiguide.com (opens in new tab)  have a solution. Their suggestion is to buy one, but then replant your cacti into proper pots after several months.

'The hardy drought-resistant nature of these plants means that they will make an attractive mini-desert terrarium that can last for several months,' they explain.  'Nevertheless, they will slowly begin to die off over the course of a year or maybe even two depending on the plants and conditions.'

'While that may seem like a long time, most cactus will grow for many decades when properly cared for and produce some of the most outstanding flowers of any type of plant.'

Once you've replanted your cactus, you can still enjoy your terrarium – just with humidity-loving plants inside it. 

• Read more: Caring for indoor plants in winter - how to help your houseplants thrive in the colder months