Fertilising guide
How to fertilise Custard Apple (Annona reticulata)— schedule & NPK
Also called Custard Apple, Bullock's Heart, Ox Heart, Red Custard Apple.
More about custard apple
About Custard Apple
Annona reticulata · also called Custard Apple, Bullock's Heart · tropical
A semi-deciduous tropical tree from the Americas producing large, heart-shaped fruits with pale, creamy flesh and a sweet, custard-like flavour. Requires full sun, warm humid conditions, and consistent moisture for good fruit production. Frost-tender but can tolerate brief periods down to about -2°C when mature. Seeds and leaves contain toxic acetogenins.
Growth habit: Semi-deciduous small to medium tree with an upright, sometimes irregular crown
What fertiliser custard apple actually wants — and why
Custard Apple 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 custard apple: 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 custard apple, 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 custard apple:
Apply a balanced slow-release fertiliser (NPK 8-3-9 or similar) three times per year in spring, early summer, and late summer. Once fruiting, increase potassium feeds to promote flavour. Avoid high-nitrogen feeds that stimulate leaf growth at the expense of flowers. 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 custard apple 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 custard apple
Half strength is the safe default for custard apple — 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 custard apple first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the custard apple watering schedule.
Signs you are over-feeding custard apple
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for custard apple:
- 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 custard apple
- 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 custard apple care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of custard apple 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 custard apple
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 custard apple — frequently asked questions
What fertiliser does custard apple 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. Custard Apple 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 custard apple?
Apply a balanced slow-release fertiliser (NPK 8-3-9 or similar) three times per year in spring, early summer, and late summer. Once fruiting, increase potassium feeds to promote flavour. Avoid high-nitrogen feeds that stimulate leaf growth at the expense of flowers. Apply a balanced slow-release fertiliser (NPK 8-3-9 or similar) three times per year in spring, early summer, and late summer. Once fruiting, increase potassium feeds to promote flavour. Avoid high-nitrogen feeds that stimulate leaf growth at the expense of flowers. 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 custard apple?
Half strength is the safe default for custard apple — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding custard apple 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 custard apple 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 custard apple?
Flush the pot of custard apple 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
- Custard Apple care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water custard apple — 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 nepenthes clipeata
- How to fertilise nepenthes macrophylla
- How to fertilise nepenthes edwardsiana
- All 8452 fertilising guides in the Growli library