Fertilising guide
How to fertilise Tamanu (Calophyllum inophyllum)— schedule & NPK
Also called Tamanu, Alexandrian Laurel, Beach Calophyllum, Poon Tree, Kamani.
More about tamanu
About Tamanu
Calophyllum inophyllum · also called Tamanu, Alexandrian Laurel · tropical
Tamanu is a large coastal tropical tree prized for its dense, glossy canopy and oil-rich seeds used in skincare. It thrives in full sun, tolerates salt spray and sandy soils, and produces fragrant white flowers followed by round yellow-green drupes. Best suited to humid, frost-free climates with warm temperatures year-round.
Growth habit: Large, spreading evergreen tree with a broad, dense rounded canopy
What fertiliser tamanu actually wants — and why
Tamanu 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 tamanu: 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 tamanu, 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 tamanu:
Feed with a balanced slow-release fertiliser (10-10-10 or similar) in spring and mid-summer. Young trees benefit from light nitrogen supplementation to encourage canopy establishment. Avoid heavy fertilising on established trees in poor soils — they are naturally adapted to nutrient-sparse coastal conditions. 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 tamanu 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 tamanu
Half strength is the safe default for tamanu — 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 tamanu first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the tamanu watering schedule.
Signs you are over-feeding tamanu
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for tamanu:
- 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 tamanu
- 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 tamanu care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of tamanu 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 tamanu
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 tamanu — frequently asked questions
What fertiliser does tamanu 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. Tamanu 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 tamanu?
Feed with a balanced slow-release fertiliser (10-10-10 or similar) in spring and mid-summer. Young trees benefit from light nitrogen supplementation to encourage canopy establishment. Avoid heavy fertilising on established trees in poor soils — they are naturally adapted to nutrient-sparse coastal conditions. Feed with a balanced slow-release fertiliser (10-10-10 or similar) in spring and mid-summer. Young trees benefit from light nitrogen supplementation to encourage canopy establishment. Avoid heavy fertilising on established trees in poor soils — they are naturally adapted to nutrient-sparse coastal conditions. 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 tamanu?
Half strength is the safe default for tamanu — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding tamanu 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 tamanu 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 tamanu?
Flush the pot of tamanu 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
- Tamanu care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water tamanu — 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 rambutan
- How to fertilise pulasan
- How to fertilise salak
- All 8452 fertilising guides in the Growli library