Fertilising guide
How to fertilise Reunion Island Begonia (Begonia salaziensis)— schedule & NPK
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.
Growth habit: Compact, upright fibrous-rooted perennial with a tidy bushy form.
What fertiliser reunion island begonia actually wants — and why
Reunion Island Begonia is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.
A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula.
For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for reunion island begonia: match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.
How often to feed reunion island begonia, and which months
Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For reunion island begonia:
Apply a dilute (quarter-strength) balanced liquid feed every two to three weeks during active growth; the species is sensitive to fertiliser burn so err on the side of under-feeding. Treat that as sparingly through the growing season between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.
The dormant-season rule matters more than the exact interval: skip feeding entirely when reunion island begonia is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.
What strength to mix for reunion island begonia
Half strength is the safe default for reunion island begonia — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
Feeding always goes onto already-damp soil, never dry roots — water reunion island begonia first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the reunion island begonia watering schedule.
Signs you are over-feeding reunion island begonia
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for reunion island begonia:
- Brown, crispy leaf tips and edges with no sign of underwatering.
- A white, crusty salt deposit on the soil surface or pot rim.
- Weak, pale, stretched new growth that flops.
- Lower leaves yellow and drop while the soil is correctly watered.
Signs you are under-feeding reunion island begonia
- Uniformly pale or yellow-green leaves, oldest first.
- Noticeably small new leaves and stalled growth in good light and season.
- A generally tired, lacklustre look despite correct watering and light.
If the symptoms point at watering, light or roots rather than nutrition, the full reunion island begonia care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of reunion island begonia with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.
Organic vs synthetic feeds for reunion island begonia
Organic options
A diluted seaweed or worm-casting feed, or fish emulsion if you can tolerate the smell indoors. UK: Westland or Baby Bio Organic, dilute seaweed; US: Espoma Indoor! or Neptune's Harvest fish & seaweed. Slow, gentle and hard to overdo.
Synthetic / liquid feeds
A general-purpose houseplant liquid at half strength — UK: Baby Bio, Westland Houseplant Feed or Phostrogen; US: Miracle-Gro Indoor Plant Food or Schultz. Convenient and fast-acting; the only risk is overdoing it.
Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.
Fertilising reunion island begonia — frequently asked questions
What fertiliser does reunion island begonia need?
A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula. Reunion Island Begonia is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.
How often should I feed reunion island begonia?
Apply a dilute (quarter-strength) balanced liquid feed every two to three weeks during active growth; the species is sensitive to fertiliser burn so err on the side of under-feeding. Apply a dilute (quarter-strength) balanced liquid feed every two to three weeks during active growth; the species is sensitive to fertiliser burn so err on the side of under-feeding. Treat that as sparingly through the growing season between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.
What strength of feed for reunion island begonia?
Half strength is the safe default for reunion island begonia — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding reunion island begonia look like?
Brown, crispy leaf tips and edges with no sign of underwatering. A white, crusty salt deposit on the soil surface or pot rim. Weak, pale, stretched new growth that flops. Lower leaves yellow and drop while the soil is correctly watered. Feeding reunion island begonia year-round on a fixed schedule, including dark winter months, is the most common mistake — it cannot use the nutrients in low light and the surplus simply burns the roots and crusts the soil.
Should I flush the soil of reunion island begonia?
Flush the pot of reunion island begonia with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.
Keep reading
- Reunion Island Begonia care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water reunion island begonia — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
- How to fertilise schismatoglottis wallichii
- How to fertilise schismatoglottis calyptrata
- How to fertilise schismatoglottis motleyana
- All 10153 fertilising guides in the Growli library