Soil & potting mix
Best soil for Reunion Island Begonia (Begonia salaziensis)
Also called Reunion Island begonia, Salazie begonia.
More about reunion island begonia
About Reunion Island Begonia
Begonia salaziensis · also called Reunion Island begonia, Salazie begonia · tropical
Begonia salaziensis is a rare fibrous-rooted species endemic to the cloud-forest habitats of Réunion Island in the Indian Ocean, where it grows as an understorey plant in cool, misty conditions. It produces attractive foliage and small pink to white flowers, preferring consistently cool temperatures that distinguish it from most tropical begonias. The single most critical care point is to keep temperatures below 25 °C, as prolonged heat causes rapid decline in this naturally cool-adapted species. This plant is toxic to cats and dogs.
Preferred mix: Humus-rich, free-draining compost
Why reunion island begonia needs this mix
Reunion Island Begonia wants a light, fine, evenly moist mix — soft-rooted and crown-sensitive, it suits an airy 1:1:1 blend, not heavy compost.
- Reunion Island Begonia has fine, shallow roots and a crown that rots if it sits wet, so the mix must be light, airy and only evenly moist.
- Equal parts compost, perlite and vermiculite give steady moisture and plenty of air at once — the balance this plant flowers on.
- A heavy, dense mix smothers the fine roots and is the usual reason it sulks and refuses to bloom.
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 reunion island begonia struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:
- Heavy, water-holding compost rots reunion island begonia's crown and fine roots — the plant goes limp and mushy at the centre.
- A coarse, gritty cactus-style mix dries too fast and the fine roots desiccate.
- Burying the crown when potting (rather than keeping it just at the surface) causes rot even in a good mix.
Using heavy compost and burying the crown. Reunion Island Begonia wants a light 1:1:1 mix with the crown sitting right at the surface.
pH — does it matter for reunion island begonia?
Reunion Island Begonia is not fussy about pH — a slightly acidic to neutral mix (around pH 6.0-7.0), which a standard peat-free compost provides, is perfectly fine. No testing needed.
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 decent bagged houseplant compost works for reunion island begonia as long as you mix in perlite for air. The simple DIY ratio above is cheap and more reliable than a budget bag alone.
Drainage and the pot
Use a small pot with a drainage hole and water from the bottom to keep the crown dry — wet leaves and a wet crown are this plant's main enemies.
Refresh reunion island begonia's mix every 18-24 months; even good compost slumps and compacts, and fresh, airy mix is often the simplest fix for a tired plant. When the time comes, our repotting guide for reunion island begonia covers the timing and technique step by step.
Reunion Island Begonia soil — frequently asked questions
What is the best soil mix for reunion island begonia?
1 part peat-free houseplant compost : 1 part perlite : 1 part vermiculite. Reunion Island Begonia has fine, shallow roots and a crown that rots if it sits wet, so the mix must be light, airy and only evenly moist.
Can I use normal potting soil for reunion island begonia?
Heavy, water-holding compost rots reunion island begonia's crown and fine roots — the plant goes limp and mushy at the centre. A decent bagged houseplant compost works for reunion island begonia as long as you mix in perlite for air. The simple DIY ratio above is cheap and more reliable than a budget bag alone.
Does reunion island begonia need a special pH?
Reunion Island Begonia is not fussy about pH — a slightly acidic to neutral mix (around pH 6.0-7.0), which a standard peat-free compost provides, is perfectly fine. No testing needed.
Should I buy a bagged mix or make my own for reunion island begonia?
A decent bagged houseplant compost works for reunion island begonia as long as you mix in perlite for air. The simple DIY ratio above is cheap and more reliable than a budget bag alone.
How often should I refresh the soil for reunion island begonia?
Refresh reunion island begonia's mix every 18-24 months; even good compost slumps and compacts, and fresh, airy mix is often the simplest fix for a tired plant. Use a small pot with a drainage hole and water from the bottom to keep the crown dry — wet leaves and a wet crown are this plant's main enemies.
Keep reading
- Reunion Island Begonia care — the full brief (light, water, humidity, problems, pet safety)
- How often to water reunion island begonia — the schedule the mix feeds into
- Repotting reunion island begonia — when and how to refresh the mix
- Soil pH guide — test it and adjust it safely
- Should I water my plant? The simple check first
- Overwatered plant — signs and recovery
- Root rot — how the wrong soil starts it, and how to save the plant
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- Best soil for schismatoglottis calyptrata
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- All 10153 soil and potting-mix guides in the Growli library