Can you guess what the problem is with the terrarium in our main picture? I'll help you- it will never survive indoors for longer than a month. Terrariums are incredibly popular, but if I got a dollar for every person that have either emailed us or talked to us at our plant market stall about their failed attempt at growing succulent terrariums I’d be a very rich woman.
Succulents have skyrocketed in popularity and so have websites providing advice about how to care for them. Having had a look at what comes up top in search engines when you look for information about succulents and terrariums I just could not believe the amount of information that is so completely and utterly wrong.
This article was written to set the record straight on succulent terrariums and help anyone who would like to make a succulent terrarium or have previously failed and would like to try again.
Unfortunately, succulents are not the best plants to be putting in terrariums and small, slow growing, leafy indoor plants are a much better choice. However, it is possible to make one with a few select succulents that should be able to survive growing in a terrarium.
To make a succulent terrarium that will survive indoors you will need shade and humidity tolerant succulents, a terrarium with a wide opening, quality succulent potting mix and a very bright spot in an airy, light-filled room.
I have been growing succulents for the past 10 years, 8 commercially. I was first drawn to succulents because of terrariums and how gorgeous they looked. But it very soon became apparent that the majority will not grow indoors, let alone in a terrarium.
At the time my old 5 acre nursery was transitioning from growing foliage for florists to growing succulents and I have been experimenting with many different species over the years. Below I will share some of the findings and provide advice on how to get a succulent terrarium together and care for it long term.
Are Succulents Good For Terrariums
The majority of succulents are just not suited to a life in terrariums. In general succulents come from dry and arid regions, though there are exceptions. Most succulents also very much like being exposed to at least some sun though just how much sun will differ from species to species.
While there are shade tolerant succulents out there, most will like an airy spot which is very hard to achieve in a terrarium as they can have very small openings.
A few succulent species can be found in jungles and humid areas and they should be fine in a terrarium setting.
If you’re not too fussed about the type of plants, the best thing would be to look for leafy shade plants that will be happy with the humidity and the almost inevitable wet feet as terrariums usually do not have drainage holes.
But, if you have your heart is set on succulents, read on.
Which Succulents Are Best For Terrariums?
Haworthia Bayeri species
Haworthia Fasciata species that grow tall rather than wide
Any small growing Haworthia
Gasteria Banded Pearls
Rhipsalis Cereuscula and other Rhipsalis species
The list for succulents that can grow in terrarium is not going to be very long as the succulents will need to be slow growing, tolerant of shade and to some degree, humidity.
Unfortunately, it also does not include any of the beautiful, colourful rosette succulents that make this group of plants so desirable. I’ve seen advice out there that said all you need is some small succulents and that any succulent is perfect for a terrarium as they grow slow. This is not the case at all. Most succulents would stretch, grow from the middle and then slowly rot in a terrarium.
Succulents that should survive a life in a terrarium are mostly a shade of green, but there is a good enough variety to create a pretty terrarium. In my own experiments I had most luck with smaller growing Haworthia, Gasteria, Rhipsalis and some succulent Peperomia.
When choosing succulents for a terrarium go for plants that do not grow very big and stay about 8cm in diameter. This can be quite difficult as some Haworthia and Gasteria species will grow much larger than that.
Although, succulent are unlikely to grow to their full size indoors and their growth rate will slow down dramatically, it is always good to for the smaller ones. Also, choose plants that already have decent root-ball formed as they will cope better.
What Are The Worst Succulents For Terrariums?
Any succulents that need exposure to the sun
What Will You Need To Plant A Succulent Terrarium?
Your choice of shade tolerant succulents
A terrarium with large opening/ slant cut
Succulent Potting Mix
Pebbles, Rocks to decorate
Some of you may be thinking that this is a little bit too short of a list, missing things like charcoal, sphagnum moss, sand etc. I’ve experimented with lots of these ingredients and they make very little difference in the long term. It is said that charcoal will help to keep things in balance and stop build-up of algae and keep the terrarium fresh and clean. In my experience, the algae will grow even with the charcoal in the mix and the results are the same when compared to a terrarium without charcoal.
The best thing you can do for the succulents wellbeing is to get a terrarium that is slant cut and quite big (over 15cm/6inch in diameter). This will ensure that the plants will get enough fresh air and the water will evaporate out of the potting mix without any trouble. Failing that, a large opening will be ok but, slant cut bowl is by far the best choice.
Good potting mix will also make a world of difference. A proper succulent potting mix should not smell and it can’t have anything like compost or animal manure in it as they are high in nitrogen. Succulents dislike lots of nitrogen and are unlikely to grow well in poor potting mix. At the same time the mix should be light and fluffy, well-draining but also be able to retain some water so the plants do get a chance to drink.
Pebbles, Rocks and even miniature figurines can be used for decoration. This is where imagination comes to play and you can really personalize your terrarium. I’ve seen some awesome designs over the years, such as desert scenes complete with skulls, dinosaur terrariums and even a hobbit village.
How To Make A Succulent Terrarium?
Get your slant cut bowl and put potting mix in
Take your shade tolerant succulents out of their pots (3-4 plants)
Arrange them in the bowl
Make sure they have a bit of space around them to grow a bit
Decorate with pebbles
That’s it. Making a terrarium should be kept simple. I’d advise to keep the potting mix visible so you can see what is going on in there. In my opinion and experience different layers of other stuff or putting rocks at the bottom makes no difference for one reason- in time the plants will grow roots all the way through the terrarium.
So, if there are rocks at the bottom to stop the water saturating the potting mix, the roots will just grow in there, all the way down. If there is sphagnum moss to suck out the moisture out of the soil, the roots will grow into it as well and they will pretty much be in this constantly wet sponge.
I think it is well worth it to keep the potting mix exposed on the sides and not hide it with rock rocks or sand. You will eventually see the roots and it may not be as pretty as having nice pebbles, but it will show you when you need to water and the overall health of the terrarium.
How Often Do You Water Succulents In A Terrarium?
Watering a terrarium will depend on the location and the temperature of your house. In the warmer months, the plants in the terrarium may need water once every 2 weeks and in cooler months, it could be once a month.
Seeing the potting mix will help you determine if the plants need water. If the mix is dark colour and looks wet, then it is best to wait until it dries out into a lighter colour. This will also stop algae & fungi from growing as they thrive in moist environment.
How To Look After A Succulent Terrarium?
Place the terrarium somewhere bright
A little bit of sun won’t hurt, unless very hot
Water when needed
Trim trailing plants taking over
Re-pot when plants get too big
Brighter the spot, better your succulents will grow. If its too dark, the plants will start stretching towards a source of light and will be more likely to rot. If there is a bit of sun coming through the windows and hitting your terrarium, that is fine most of the time.
The only time this could hurt and even cook your plants is when its very hot and the sun’s rays are too strong, their intensity amplified by the glass.
Some plants such as the Rhipsalis or trailing plants can take over the terrarium, but they can be trimmed back. Unfortunately, plants such as the Haworthia or Gasteria cannot just have bits of their leaves chopped off and they will have to be left alone. If offsets appear, they can be pinched off.
No matter what you do, some plants will just get too big for the terrarium and will eventually have to be re-potted. This may take years, depending on the species you choose.
What NOT To Do With A Succulent Terrarium
Never mist succulents in a terrarium
Do not give the terrarium sun randomly
Do not use lots of fertilizer
Do not overwater
Do not place terrariums in dark rooms
My absolute pet peeve is when there is advice to mist succulents in terrariums (or just mist succulents in general). Succulents do not like to be misted and have their foliage wet.
Misting will also not deliver enough water to the roots as that is how most succulents drink their water. The best approach is to water well once every now and again. Well enough that the potting mix gets wet but not soggy. There should be no water sitting at the bottom of the terrarium.
Another thing I hear from my customers often is that they try and ‘give’ their indoor succulents sun. This, in my opinion, is not a good long-term solution as plants can sustain burns easily this way, especially in the warmer months when the sun's UV is too strong.
Finding the right spot and not growing sun loving succulents indoors is far more important.
To not encourage growth, fertilizer should be limited. Succulents are not massive fans of fertilizer anyway, though a few balls of slow release fertilizer every spring can help them stay healthy.
Avoid fertilizer high in Nitrogen and I would advise to not use liquid fertilizer at all.
Do not overwater is an obvious one. Water should never sit at the bottom of the bowl.
The last advice would be to expect a plant can die. This can happen despite your best efforts and has happened to me many a time. Succulents are living, breathing things that may react to changes in environment, temperature and other factors.
I do wish everyone best of luck with creating their masterpieces. You can share your experience with terrariums below, in the comments.