Soil & potting mix
Best soil for Tasmanian Tree Fern (Dicksonia squarrosa)
Also called Rough Tree Fern (NZ), Wheki, Slender Tree Fern.
More about tasmanian tree fern
About Tasmanian Tree Fern
Dicksonia squarrosa · also called Rough Tree Fern (NZ), Wheki · tropical
The Tasmanian Tree Fern (Wheki) is a stately New Zealand native tree fern forming a slender fibrous trunk topped with spreading, dark green, bipinnate fronds. Considerably more cold-tolerant than many tree ferns, it can be grown outdoors in mild UK and Pacific Northwest climates. True ferns are generally considered non-toxic to pets.
Preferred mix: Rich, moisture-retentive, humus-rich woodland soil or compost
Watch for — Trunk drying out: Fatal if prolonged — water the trunk directly in dry spells, not just the soil. The fibrous trunk absorbs moisture for the fronds.
Why tasmanian tree fern needs this mix
Tasmanian Tree Fern hates drying out, so it wants a mix that stays evenly moist — but it still needs perlite so "moist" never tips into "waterlogged".
- Tasmanian Tree Fern comes from damp, shaded forest floors and has fine roots that scorch and brown the moment the rootball dries — the mix has to hold a steady reserve.
- Coir and compost give that reserve, while perlite keeps enough air that the constantly-moist mix does not turn anaerobic.
- Even moisture also keeps its thin leaves from crisping at the edges, which is this plant’s most visible stress signal.
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 tasmanian tree fern struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:
- A free-draining, gritty mix dries too fast for tasmanian tree fern — you get crispy brown edges and frond or leaf drop within days of one missed watering.
- A pure, airless peat mix swings the other way: it holds water but suffocates the fine roots and rots the crown.
- Letting the mix dry to the point it shrinks from the pot is very hard to re-wet evenly and stresses the plant badly.
Using a sharp, fast-draining "houseplant" or cactus-leaning mix that lets tasmanian tree fern dry out. It needs a moisture-retentive but still airy blend.
pH — does it matter for tasmanian tree fern?
Tasmanian Tree Fern prefers a slightly acidic mix (around pH 5.5-6.5); a peat-free compost-and-coir blend sits there naturally, so routine pH testing is unnecessary.
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
A good peat-free houseplant compost works for tasmanian tree fern straight from the bag if you mix in some perlite for air. The DIY ratio above gives a more reliable moisture-to-air balance.
Drainage and the pot
Use a pot with a drainage hole but a less-porous material (plastic or glazed) so it does not dry too fast. Bottom-watering keeps the mix evenly moist without sogging the crown.
Peat-free mixes slump and compact as they hold moisture, so refresh tasmanian tree fern's mix every 12-18 months to keep air in the rootball even if the pot size is unchanged. When the time comes, our repotting guide for tasmanian tree fern covers the timing and technique step by step.
Tasmanian Tree Fern soil — frequently asked questions
What is the best soil mix for tasmanian tree fern?
3 parts peat-free houseplant compost : 1 part coco coir : 1 part perlite. Tasmanian Tree Fern comes from damp, shaded forest floors and has fine roots that scorch and brown the moment the rootball dries — the mix has to hold a steady reserve.
Can I use normal potting soil for tasmanian tree fern?
A free-draining, gritty mix dries too fast for tasmanian tree fern — you get crispy brown edges and frond or leaf drop within days of one missed watering. A good peat-free houseplant compost works for tasmanian tree fern straight from the bag if you mix in some perlite for air. The DIY ratio above gives a more reliable moisture-to-air balance.
Does tasmanian tree fern need a special pH?
Tasmanian Tree Fern prefers a slightly acidic mix (around pH 5.5-6.5); a peat-free compost-and-coir blend sits there naturally, so routine pH testing is unnecessary.
Should I buy a bagged mix or make my own for tasmanian tree fern?
A good peat-free houseplant compost works for tasmanian tree fern straight from the bag if you mix in some perlite for air. The DIY ratio above gives a more reliable moisture-to-air balance.
How often should I refresh the soil for tasmanian tree fern?
Peat-free mixes slump and compact as they hold moisture, so refresh tasmanian tree fern's mix every 12-18 months to keep air in the rootball even if the pot size is unchanged. Use a pot with a drainage hole but a less-porous material (plastic or glazed) so it does not dry too fast. Bottom-watering keeps the mix evenly moist without sogging the crown.
Keep reading
- Tasmanian Tree Fern care — the full brief (light, water, humidity, problems, pet safety)
- How often to water tasmanian tree fern — the schedule the mix feeds into
- Repotting tasmanian tree fern — when and how to refresh the mix
- Soil pH guide — test it and adjust it safely
- Underwatered plant — signs and how to rehydrate it
- Why is my plant wilting? Wet vs dry diagnosis
- Should I water my plant? The simple check first
- Best soil for gurken's orthophytum
- Best soil for boat-shaped orthophytum
- Best soil for white air plant
- All 11687 soil and potting-mix guides in the Growli library