Growli
Let's go

Fertilising guide

How to fertilise Longan (Nephelium longana)— schedule & NPK

Also called Longan, Dragon's Eye, Dimocarpus longan.

More about longan

About Longan

Nephelium longana · also called Longan, Dragon's Eye · tropical

Longan is a fast-growing subtropical to tropical fruit tree in the Sapindaceae family, prized for translucent, sweet arils. It is self-fertile, begins fruiting relatively early, and tolerates brief mild cold spells better than its close relative lychee. Best grown outdoors in frost-free climates; thrives in full sun with well-draining slightly acidic soil.

Growth habit: Dense, spreading evergreen tree with a rounded to irregular crown; pinnately compound leaves

What fertiliser longan actually wants — and why

Longan is an acid-loving plant — it can only take up nutrients in acidic soil, so the feed itself matters less than using an ericaceous formula and never liming.

An ericaceous (acidic) fertiliser, formulated to keep the soil pH low and supply iron and trace elements in a form acid-loving roots can absorb. Ordinary feeds and any lime lock out iron and yellow the leaves.

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 longan: 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 longan, 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 longan:

Apply a balanced fruit-tree fertilizer (8-3-9 NPK or similar) four times per year: late winter, late spring, midsummer, and early autumn. Avoid heavy nitrogen applications in late summer, which can delay flowering. A foliar potassium spray in late summer promotes fruit quality. In practice: an ericaceous feed in spring as growth resumes, repeated through the main growing months; never apply lime, bonemeal or wood ash, which raise pH.

The dormant-season rule matters more than the exact interval: skip feeding entirely when longan 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 longan

Follow the ericaceous product's own rate — these are formulated for the plant, so the dilution on the label is right for longan. The variable that actually matters is pH, not concentration.

Feeding always goes onto already-damp soil, never dry roots — water longan first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the longan watering schedule.

Signs you are over-feeding longan

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for longan:

Signs you are under-feeding longan

If the symptoms point at watering, light or roots rather than nutrition, the full longan care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Flush longan with rainwater (not hard tap water, which raises pH) if salts build up; better still, mulch with pine needles or composted bark and water with rainwater to hold the acidity.

Organic vs synthetic feeds for longan

Organic options

Composted pine bark, pine-needle mulch, used coffee grounds and an organic ericaceous feed gently maintain acidity. UK: Vitax or Westland Ericaceous; US: Espoma Holly-tone or Dr. Earth Acid Lovers. Slow, soil-improving, hard to overdo.

Synthetic / liquid feeds

A liquid or granular ericaceous feed — UK: Miracle-Gro Ericaceous, Vitax or Westland; US: Miracle-Gro Acid-Loving Plant Food or Espoma Holly-tone. Pair with rainwater and an acidic mulch for it to work.

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 longan — frequently asked questions

What fertiliser does longan need?

An ericaceous (acidic) fertiliser, formulated to keep the soil pH low and supply iron and trace elements in a form acid-loving roots can absorb. Ordinary feeds and any lime lock out iron and yellow the leaves. Longan is an acid-loving plant — it can only take up nutrients in acidic soil, so the feed itself matters less than using an ericaceous formula and never liming.

How often should I feed longan?

Apply a balanced fruit-tree fertilizer (8-3-9 NPK or similar) four times per year: late winter, late spring, midsummer, and early autumn. Avoid heavy nitrogen applications in late summer, which can delay flowering. A foliar potassium spray in late summer promotes fruit quality. Apply a balanced fruit-tree fertilizer (8-3-9 NPK or similar) four times per year: late winter, late spring, midsummer, and early autumn. Avoid heavy nitrogen applications in late summer, which can delay flowering. A foliar potassium spray in late summer promotes fruit quality. In practice: an ericaceous feed in spring as growth resumes, repeated through the main growing months; never apply lime, bonemeal or wood ash, which raise pH.

What strength of feed for longan?

Follow the ericaceous product's own rate — these are formulated for the plant, so the dilution on the label is right for longan. The variable that actually matters is pH, not concentration.

What does over-feeding longan look like?

Brown, scorched leaf margins from too strong or too frequent a dose. White salt crust on the soil surface. Soft, lush growth that fruits or flowers poorly. Feeding longan an ordinary fertiliser, or growing it in hard tap water / limey soil, is the defining mistake — it triggers lime-induced chlorosis (yellow leaves, green veins) no amount of feeding fixes until the pH comes down.

Should I flush the soil of longan?

Flush longan with rainwater (not hard tap water, which raises pH) if salts build up; better still, mulch with pine needles or composted bark and water with rainwater to hold the acidity.

Keep reading