Honestly, ferns really are a terrarium lovers best friend.
They’re almost universally suited to terrarium life. They like nothing more than a warm environment with lots of humidity and plenty to drink (much like me really).
Maybe more than any other type of plant, there’s a huge variety of shapes and textures.
For me, it’s rare that a terrarium feels complete without at least one fern.
In this article, we’re going to show you where to find the best ferns for your terrarium, and how to keep them healthy and happy.
Let’s jump in.
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Why Ferns for Terrariums?
Ferns are a versatile and often hardy plant species.
They’re found naturally growing terrestrially in moist earth, and epiphytically on the trunks of trees and in the crevices of rocks.
Characterised by their unique fronds (divided leaves). They range from broad, rounded and flat to fluffy, ruffled and frilly.
Whatever “look” you’re going for in your terrarium, there’s a fern with the size, colour and texture to fit!
The Ideal Fern Growth Environment (Hint: It’s a Terrarium)
As houseplants, ferns can be somewhat demanding.
They love moisture – both around their roots and in the air around them – so dry air and cold drafts can really take their toll. Making it difficult to manage ferns in open spaces throughout the different seasons.
Not a problem for terrariums though!
A closed terrarium environment traps moisture, warmth and generates its own humidity. So terrarium ferns have ample supply of everything they need.
They’ll pair nicely with the majority of other suitable terrarium plants – see the Terrarium Plant Index for more.
Or, if you struggle with sourcing terrarium-ready plants, check out our Essential Guide to Tropical Terrariums. We teach you how to pair plants across the plant categories (including ferns, naturally) that will look amazing together AND thrive in the same conditions.
The Best Types of Ferns for Terrariums
All ferns are good ferns, I have a lot of fern love to give… But, the best terrarium ferns are generally from the tropics.
Fern species that enjoy the high temperature and humidity that a terrarium provides.
Thankfully for us, that’s a lot of ferns!
Tropical ferns come in all shapes and sizes, so there’s always an option for any given terrarium design. Also, generally speaking, most typical indoor ferns will happily grow in a terrarium – which brings me on to my next point.
Large Ferns (That Can be Easily Divided)
The best part about fern versatility is they are often able to be easily divided to create plants that are exactly the right size! (the process of which is explained more in the propagating section later).
You don’t necessarily need a small fern to begin with, you can easily “make” a small fern out of many larger common indoor ferns, e.g.
- Nephrolepis exaltata (Boston Fern) – See on Etsy
- Adiantum raddianum (Maidenhair Fern) – See on Etsy
- Asparagus setaceus (Asparagus Fern) – See on Etsy
- Phlebodium aureum (Blue Star Fern) – See on Etsy
In short, dividing a fern is simply about (lovingly) tearing or chopping a plant up into smaller plants.
It sounds barbaric – and it honestly it does feel it when you’re doing it – but you’d be surprised how many “single plants” are actually groups of smaller ones. Many will readily be teased apart.
See the tiny little Sword Ferns used in our Fittonia Terrarium?
You can get really creative in finding the perfect little plant for the various spaces in your terrariums.
Small Ferns for Terrariums
On the other hand, if you want something that’s already the right size (and you can’t bring yourself to take a pair of scissors to a larger fern) then you’re in luck – there are still lots of small ferns for terrariums.
Some of our favourite houseplant ferns actually have smaller cultivars that we can take advantage of, and there are a handful of naturally small ferns that are truly tiny.
So many potential little ferns, so little time!
Miniature Ferns (Dwarf Ferns)
Many of the more popular houseplant ferns have dwarf varieties that are a more appropriate size for terrariums.
The likes of:
- Nephrolepis cordifolia ‘Duffii’ (Lemon Button Fern) – See on Etsy
- Pellaea rotundifolia (Button Fern) – See on Etsy
- Nephrolepis exaltata ‘Fluffy Ruffles’ (Dwarf Boston Fern) – See on Etsy
- Davallia fejeensis (Rabbit’s Foot Fern) – See on Etsy
These all typically grow about 12-15 inches tall, making them great for everything but the smallest terrariums.
However, if you’re looking for a truly compact fern, you’ll want to take a look at the micro ferns.
Micro ferns are fundamentally tiny.
As in, won’t grow larger than a couple of inches kind of tiny.
Micro ferns tend to be epiphytic, as such small, delicate plants often struggle to compete for resources on the forest floor (and would be easily trampled).
If you’re building a mini terrarium or just want to add some delicate texture to your ground cover, these ferns could be a good choice for you.
- Bolbitis heteroclita ‘Difformis‘ (Mini Asian Water Fern).
- Pyrrosia piloselloides (Dragon Scale Fern).
How to Plant Terrarium Ferns (Roots vs Rhizomes)
Ferns have a range of different root structures, each with their own unique planting requirements.
Many still have a typical root ball, whereas others will have a central rhizome, or long vine-like rhizomes (some are even fluffy). Don’t worry if you’ve never heard of a rhizome before – it’s a very sciencey word for a very simple thing.
All will be explained.
For ferns with more typical root structures, they still tend to have short and delicate roots.
Which means they’re not always able to support themselves very well on first planting, and it’s important to have a nutrient rich substrate that can retain moisture well, so the shallow roots can easily find moisture (which they all love).
Fern Rhizomes (Explained!)
Epiphytic (and many terrestrial) ferns tend to grow from a creeping rhizome rather than a central root structure.
As you can hopefully make out from my (crude) diagram, a rhizome is essentially a horizontal stem which sprouts more fronds as the plant grows and expands.
In reality, they look more like a thick root than a stem.
Despite appearances, these kinds of epiphytic ferns often don’t have much in the way of roots. They instead attach themselves and absorb water via small hair-like structures on the rhizome called rhizoids.
Easily confused, I know…
So, you can often think of them as more of a vine, though sometimes rhizomes are particularly short and stubby.
So when planting/attaching epiphytic ferns, make sure they’re on a damp surface or misted regularly. It can help to saturate some Sphagnum moss in water and use that as a base to attach the fern too, instead of a dry branch surface.
How to Propagate Ferns For Your Terrarium
Ferns are ancient, non-flowering, spore producing plants with some unique parts and structures.
Which means we can’t get them from seeds, but it does offer up new ways and opportunities to get new plants from them.
Spores are the natural way that ferns typically reproduce.
They’re very effective in the wild with open air, breezes and transient wildlife. Not so effective in a sealed terrarium with no airflow.
That being said, it is possible to harvest spores from mature ferns and use them to create new plants, but it’s quite a difficult process to manage.
Here’s a guide if you’re feeling up to the task.
As mentioned earlier, by far the easiest way to propagate ferns tends to be through division.
Essentially just dividing a single larger fern into smaller viable plants. By creating sections with a good amount of fronds and roots/rhizome stretch, you can give them a fighting chance.
Depending on the type of fern, dividing the plant can be done through several ways.
Splitting Larger Ferns
The larger and bushier ferns tend to have root balls, or at least something resembling a proper root structure.
These can often be gently teased apart to form 2 or 3 smaller plants, each with their own set of fronds, stems and roots.
Splitting Creeping Rhizomes
For epiphytic ferns that grow along a creeping rhizome, you can split the rhizome itself to form viable individual cuttings.
Over to You
What ferns do you use in your terrariums? Let us know in the comments.
I’m particularly interested in hearing about exotic micro ferns.