Soil & potting mix
Best soil for Vietnamese Coriander (Persicaria odorata)
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.
Preferred mix: Rich, moisture-retentive but well-draining potting mix or garden soil
Watch for — Wilting / leaf collapse: The most common complaint, almost always from the soil drying out. This water-loving herb flops fast when thirsty but usually perks back up within hours of a thorough watering. Keep it consistently moist.
Why vietnamese coriander needs this mix
Vietnamese Coriander hates drying out, so it wants a mix that stays evenly moist — but it still needs perlite so "moist" never tips into "waterlogged".
- Vietnamese Coriander comes from damp, shaded forest floors and has fine roots that scorch and brown the moment the rootball dries — the mix has to hold a steady reserve.
- Coir and compost give that reserve, while perlite keeps enough air that the constantly-moist mix does not turn anaerobic.
- Even moisture also keeps its thin leaves from crisping at the edges, which is this plant’s most visible stress signal.
For the full picture on what makes up a good mix, see our guide to the main types of soil and potting media — it explains why each ingredient above behaves the way it does.
What goes wrong with the wrong mix
The wrong soil is one of the most common reasons vietnamese coriander struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:
- A free-draining, gritty mix dries too fast for vietnamese coriander — you get crispy brown edges and frond or leaf drop within days of one missed watering.
- A pure, airless peat mix swings the other way: it holds water but suffocates the fine roots and rots the crown.
- Letting the mix dry to the point it shrinks from the pot is very hard to re-wet evenly and stresses the plant badly.
Using a sharp, fast-draining "houseplant" or cactus-leaning mix that lets vietnamese coriander dry out. It needs a moisture-retentive but still airy blend.
pH — does it matter for vietnamese coriander?
Vietnamese Coriander prefers a slightly acidic mix (around pH 5.5-6.5); a peat-free compost-and-coir blend sits there naturally, so routine pH testing is unnecessary.
If you want to check or adjust it, the soil pH guide walks through testing and the safe ways to nudge a mix more acidic or more alkaline.
DIY mix vs a bagged one
A good peat-free houseplant compost works for vietnamese coriander straight from the bag if you mix in some perlite for air. The DIY ratio above gives a more reliable moisture-to-air balance.
Drainage and the pot
Use a pot with a drainage hole but a less-porous material (plastic or glazed) so it does not dry too fast. Bottom-watering keeps the mix evenly moist without sogging the crown.
Peat-free mixes slump and compact as they hold moisture, so refresh vietnamese coriander's mix every 12-18 months to keep air in the rootball even if the pot size is unchanged. When the time comes, our repotting guide for vietnamese coriander covers the timing and technique step by step.
Vietnamese Coriander soil — frequently asked questions
What is the best soil mix for vietnamese coriander?
3 parts peat-free houseplant compost : 1 part coco coir : 1 part perlite. Vietnamese Coriander comes from damp, shaded forest floors and has fine roots that scorch and brown the moment the rootball dries — the mix has to hold a steady reserve.
Can I use normal potting soil for vietnamese coriander?
A free-draining, gritty mix dries too fast for vietnamese coriander — you get crispy brown edges and frond or leaf drop within days of one missed watering. A good peat-free houseplant compost works for vietnamese coriander straight from the bag if you mix in some perlite for air. The DIY ratio above gives a more reliable moisture-to-air balance.
Does vietnamese coriander need a special pH?
Vietnamese Coriander prefers a slightly acidic mix (around pH 5.5-6.5); a peat-free compost-and-coir blend sits there naturally, so routine pH testing is unnecessary.
Should I buy a bagged mix or make my own for vietnamese coriander?
A good peat-free houseplant compost works for vietnamese coriander straight from the bag if you mix in some perlite for air. The DIY ratio above gives a more reliable moisture-to-air balance.
How often should I refresh the soil for vietnamese coriander?
Peat-free mixes slump and compact as they hold moisture, so refresh vietnamese coriander's mix every 12-18 months to keep air in the rootball even if the pot size is unchanged. Use a pot with a drainage hole but a less-porous material (plastic or glazed) so it does not dry too fast. Bottom-watering keeps the mix evenly moist without sogging the crown.
Keep reading
- Vietnamese Coriander care — the full brief (light, water, humidity, problems, pet safety)
- How often to water vietnamese coriander — the schedule the mix feeds into
- Repotting vietnamese coriander — when and how to refresh the mix
- Soil pH guide — test it and adjust it safely
- Underwatered plant — signs and how to rehydrate it
- Why is my plant wilting? Wet vs dry diagnosis
- Should I water my plant? The simple check first
- Best soil for basil
- Best soil for herb garden
- Best soil for mint
- All 609 soil and potting-mix guides in the Growli library