Fertilising guide
How to fertilise Vietnamese Coriander (Persicaria odorata)— schedule & NPK
Also called Vietnamese coriander, Vietnamese mint, rau ram, Cambodian mint, laksa leaf, Asian mint.
More about vietnamese coriander
About Vietnamese Coriander
Persicaria odorata · also called Vietnamese coriander, Vietnamese mint · herb
Vietnamese coriander (Persicaria odorata), or rau ram, is a heat-loving Southeast Asian culinary herb with a peppery, cilantro-like flavour that does not bolt in summer heat. Give it bright light, constantly moist soil and warmth. Not listed by the ASPCA, but related buckwheat-family plants are toxic, so verify with your vet.
Growth habit: Sprawling, mat-forming evergreen perennial herb with reddish jointed stems that creep along the ground and root freely at the nodes wherever they touch soil. Grown as a tender perennial in frost-free zones and as an annual or overwintered container plant in colder climates.
What fertiliser vietnamese coriander actually wants — and why
Vietnamese Coriander is a soft, fast leafy herb that you harvest hard — a modest balanced feed keeps tender growth coming without tipping it into bland or bolting.
A balanced general feed (even N-P-K) at modest strength — enough nitrogen to keep replacing the leaves you pick, but not so much that flavour thins or it bolts to seed.
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 vietnamese coriander: 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 vietnamese coriander, 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 vietnamese coriander:
Feed with a balanced or nitrogen-leaning fertiliser about twice a month during the warm growing season and roughly once a month in cooler periods. Container plants need more frequent feeding because nutrients leach out with regular watering. Avoid over-fertilising, which can dilute the leaves' aromatic, peppery flavour. In practice: a balanced liquid feed every few weeks through the main growing and harvesting season (spring through early autumn), more often the harder you are picking it.
The dormant-season rule matters more than the exact interval: skip feeding entirely when vietnamese coriander 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 vietnamese coriander
Half strength is a sensible default for vietnamese coriander — enough to fuel regrowth after cutting, gentle enough that the leaves stay aromatic rather than watery.
Feeding always goes onto already-damp soil, never dry roots — water vietnamese coriander first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the vietnamese coriander watering schedule.
Signs you are over-feeding vietnamese coriander
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for vietnamese coriander:
- Fast, soft, pale growth with diluted, less aromatic flavour.
- Early bolting (running to flower) and a bitter edge.
- Salt crust and scorched tips on container plants.
Signs you are under-feeding vietnamese coriander
- Pale, slow regrowth after cutting and small leaves.
- A tired, stalled plant that cannot keep up with harvesting.
- Yellowing older leaves in a long-spent pot.
If the symptoms point at watering, light or roots rather than nutrition, the full vietnamese coriander care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Pot-grown vietnamese coriander builds up feed salts quickly — water until it drains each time and flush the pot with plain water every few weeks, especially on a sunny windowsill.
Organic vs synthetic feeds for vietnamese coriander
Organic options
A diluted seaweed feed or worm-casting tea keeps soft growth coming without overdoing it. UK: dilute seaweed or Westland; US: Espoma Garden-tone or Neptune's Harvest. Gentle, hard to overdo, flavour-friendly.
Synthetic / liquid feeds
A balanced liquid feed at half strength through harvesting — UK: Phostrogen, Baby Bio or Westland; US: Miracle-Gro all-purpose at half strength. Fast regrowth; just do not overdo the nitrogen.
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 vietnamese coriander — frequently asked questions
What fertiliser does vietnamese coriander need?
A balanced general feed (even N-P-K) at modest strength — enough nitrogen to keep replacing the leaves you pick, but not so much that flavour thins or it bolts to seed. Vietnamese Coriander is a soft, fast leafy herb that you harvest hard — a modest balanced feed keeps tender growth coming without tipping it into bland or bolting.
How often should I feed vietnamese coriander?
Feed with a balanced or nitrogen-leaning fertiliser about twice a month during the warm growing season and roughly once a month in cooler periods. Container plants need more frequent feeding because nutrients leach out with regular watering. Avoid over-fertilising, which can dilute the leaves' aromatic, peppery flavour. Feed with a balanced or nitrogen-leaning fertiliser about twice a month during the warm growing season and roughly once a month in cooler periods. Container plants need more frequent feeding because nutrients leach out with regular watering. Avoid over-fertilising, which can dilute the leaves' aromatic, peppery flavour. In practice: a balanced liquid feed every few weeks through the main growing and harvesting season (spring through early autumn), more often the harder you are picking it.
What strength of feed for vietnamese coriander?
Half strength is a sensible default for vietnamese coriander — enough to fuel regrowth after cutting, gentle enough that the leaves stay aromatic rather than watery.
What does over-feeding vietnamese coriander look like?
Fast, soft, pale growth with diluted, less aromatic flavour. Early bolting (running to flower) and a bitter edge. Salt crust and scorched tips on container plants. Over-feeding vietnamese coriander with strong nitrogen is the usual mistake — it grows fast and lush but the leaves turn bland and it bolts to flower sooner, ending the useful harvest early.
Should I flush the soil of vietnamese coriander?
Pot-grown vietnamese coriander builds up feed salts quickly — water until it drains each time and flush the pot with plain water every few weeks, especially on a sunny windowsill.
Keep reading
- Vietnamese Coriander care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water vietnamese coriander — 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 basil
- How to fertilise herb garden
- How to fertilise mint
- All 609 fertilising guides in the Growli library