Fertilising guide
How to fertilise Hygrophila polysperma (Hygrophila polysperma)— schedule & NPK
Also called dwarf hygro, Indian swampweed.
More about hygrophila polysperma
About Hygrophila polysperma
Hygrophila polysperma · also called dwarf hygro, Indian swampweed · tropical
Hygrophila polysperma, dwarf hygro, is one of the fastest, hardiest stem plants in the aquarium hobby, with light-green oval leaves on upright stems. It tolerates low light, a wide temperature range and neglect, making it ideal for beginners. Note it is a federally listed noxious weed in the US and must never be released into waterways.
Growth habit: Fast-growing erect stem plant with opposite oval leaves; trims and replants easily, quickly forming a dense background or midground hedge.
Watch for — Lower-leaf melt and yellowing: Fast uptake outpaces dosing, so lower leaves yellow and drop; raise nitrogen, potassium and iron in the water column.
What fertiliser hygrophila polysperma actually wants — and why
Hygrophila polysperma 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 hygrophila polysperma: 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 hygrophila polysperma, 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 hygrophila polysperma:
A fast grower that draws heavily on water-column nutrients; dose a complete liquid fertiliser with extra nitrogen, potassium and iron to prevent deficiency. Responds strongly to CO2 but grows fine without it. 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 hygrophila polysperma 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 hygrophila polysperma
Half strength is the safe default for hygrophila polysperma — 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 hygrophila polysperma first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the hygrophila polysperma watering schedule.
Signs you are over-feeding hygrophila polysperma
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for hygrophila polysperma:
- 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 hygrophila polysperma
- 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 hygrophila polysperma care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of hygrophila polysperma 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 hygrophila polysperma
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 hygrophila polysperma — frequently asked questions
What fertiliser does hygrophila polysperma 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. Hygrophila polysperma 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 hygrophila polysperma?
A fast grower that draws heavily on water-column nutrients; dose a complete liquid fertiliser with extra nitrogen, potassium and iron to prevent deficiency. Responds strongly to CO2 but grows fine without it. A fast grower that draws heavily on water-column nutrients; dose a complete liquid fertiliser with extra nitrogen, potassium and iron to prevent deficiency. Responds strongly to CO2 but grows fine without it. 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 hygrophila polysperma?
Half strength is the safe default for hygrophila polysperma — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding hygrophila polysperma 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 hygrophila polysperma 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 hygrophila polysperma?
Flush the pot of hygrophila polysperma 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
- Hygrophila polysperma care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water hygrophila polysperma — 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 monstera
- How to fertilise pothos
- How to fertilise fiddle leaf fig
- All 5561 fertilising guides in the Growli library