Soil & potting mix
Best soil for Hound's Tongue Fern (Microsorum pustulatum)
Also called Hound's Tongue Fern, Hound's Tongue, Kangaroo Fern, Fragrant Fern.
More about hound's tongue fern
About Hound's Tongue Fern
Microsorum pustulatum · also called Hound's Tongue Fern, Hound's Tongue · houseplant
Microsorum pustulatum is an epiphytic Australasian fern with glossy, leathery, tongue-shaped fronds that spread from a creeping, scaly surface rhizome. It is considerably tougher than many indoor ferns, tolerating average humidity and lower light. Not individually listed by ASPCA; treat with caution around pets until formally assessed.
Preferred mix: Coarse, humusy, epiphyte-friendly fern mix
Watch for — Yellowing or mushy fronds: Overwatering and poor drainage leading to root or rhizome rot. Let the top of the mix dry slightly between waterings, ensure the pot drains freely, and never bury the creeping rhizome.
Why hound's tongue fern needs this mix
Hound's Tongue Fern is an epiphyte — in the wild its roots grip tree bark in open air, so it must be grown in chunky bark, never in potting soil.
- Hound's Tongue Fern's thick green roots photosynthesise and need air and light — bark holds them loosely while letting them breathe and dry between waterings.
- Bark drains almost instantly, then dries, which is exactly the soak-then-dry cycle an epiphyte root expects on a tree branch.
- The chunky structure stops the roots ever sitting in stagnant water, the single thing they cannot tolerate.
For the full picture on what makes up a good mix, see our guide to the main types of soil and potting media — it explains why each ingredient above behaves the way it does.
What goes wrong with the wrong mix
The wrong soil is one of the most common reasons hound's tongue fern struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:
- Potting soil suffocates hound's tongue fern within months — the roots stay wet, go brown and hollow, and the plant slowly collapses even while the leaves look fine at first.
- Fine, broken-down old bark behaves like soil and is the leading cause of orchid root rot — this is why the medium itself has a shelf life.
- Packing moss tightly around the roots traps water against them and rots them just as fast as soil.
Ever using ordinary compost or "houseplant soil" for hound's tongue fern, or leaving it in old, decomposed bark for years. Fresh, coarse bark is non-negotiable.
pH — does it matter for hound's tongue fern?
Orchid bark sits slightly acidic (around pH 5.5-6.5) as it ages, which suits hound's tongue fern well. Testing pH is unnecessary; replacing spent bark on time matters far more.
If you want to check or adjust it, the soil pH guide walks through testing and the safe ways to nudge a mix more acidic or more alkaline.
DIY mix vs a bagged one
Bagged "orchid bark mix" is genuinely good for hound's tongue fern and the easiest correct choice — just buy a coarse grade, not fine. Adding a little perlite or charcoal from the ratio above extends its life.
Drainage and the pot
Use a pot with many holes (or a clear orchid pot) so roots get air and light and water never pools. Stand it in a cover pot only briefly while it drains, then tip every drop away.
Bark decomposes — repot hound's tongue fern into fresh coarse bark every 1-2 years, ideally just after flowering, the moment the mix starts to look broken-down and soggy. When the time comes, our repotting guide for hound's tongue fern covers the timing and technique step by step.
Hound's Tongue Fern soil — frequently asked questions
What is the best soil mix for hound's tongue fern?
4 parts coarse fir or pine orchid bark : 1 part perlite or horticultural charcoal : 1 part sphagnum moss (optional, for dry homes). Hound's Tongue Fern's thick green roots photosynthesise and need air and light — bark holds them loosely while letting them breathe and dry between waterings.
Can I use normal potting soil for hound's tongue fern?
Potting soil suffocates hound's tongue fern within months — the roots stay wet, go brown and hollow, and the plant slowly collapses even while the leaves look fine at first. Bagged "orchid bark mix" is genuinely good for hound's tongue fern and the easiest correct choice — just buy a coarse grade, not fine. Adding a little perlite or charcoal from the ratio above extends its life.
Does hound's tongue fern need a special pH?
Orchid bark sits slightly acidic (around pH 5.5-6.5) as it ages, which suits hound's tongue fern well. Testing pH is unnecessary; replacing spent bark on time matters far more.
Should I buy a bagged mix or make my own for hound's tongue fern?
Bagged "orchid bark mix" is genuinely good for hound's tongue fern and the easiest correct choice — just buy a coarse grade, not fine. Adding a little perlite or charcoal from the ratio above extends its life.
How often should I refresh the soil for hound's tongue fern?
Bark decomposes — repot hound's tongue fern into fresh coarse bark every 1-2 years, ideally just after flowering, the moment the mix starts to look broken-down and soggy. Use a pot with many holes (or a clear orchid pot) so roots get air and light and water never pools. Stand it in a cover pot only briefly while it drains, then tip every drop away.
Keep reading
- Hound's Tongue Fern care — the full brief (light, water, humidity, problems, pet safety)
- How often to water hound's tongue fern — the schedule the mix feeds into
- Repotting hound's tongue fern — when and how to refresh the mix
- Soil pH guide — test it and adjust it safely
- Root rot — how the wrong soil starts it, and how to save the plant
- Overwatered plant — signs and recovery
- Why is my plant wilting? Wet vs dry diagnosis
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- All 6887 soil and potting-mix guides in the Growli library