Fertilising guide
How to fertilise Purple Bacopa (Bacopa salzmannii)— schedule & NPK
Also called Purple Bacopa, Salzmann's Bacopa.
More about purple bacopa
About Purple Bacopa
Bacopa salzmannii · also called Purple Bacopa, Salzmann's Bacopa · tropical
Purple Bacopa is an aquatic stem plant from South America prized for its striking purple-to-violet undersides and small rounded leaves. It grows best in high-light, CO2-enriched aquariums. A slow to moderate grower, it adds rich colour contrast to planted tanks. Not listed as toxic by the ASPCA.
Growth habit: Slow to moderate-growing aquatic stem plant
Watch for — Green instead of purple coloration: Caused by low light or excess nitrogen; increase lighting intensity and reduce nitrate levels below 10 ppm.
What fertiliser purple bacopa actually wants — and why
Purple Bacopa 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 purple bacopa: 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 purple bacopa, 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 purple bacopa:
Apply a comprehensive liquid aquarium fertiliser weekly, ensuring adequate potassium and micronutrients. Iron supplementation (0.1-0.2 ppm) deepens purple pigmentation. Avoid over-fertilising with nitrogen, which shifts colour toward green. Treat that as weekly 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 purple bacopa 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 purple bacopa
Half strength is the safe default for purple bacopa — 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 purple bacopa first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the purple bacopa watering schedule.
Signs you are over-feeding purple bacopa
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for purple bacopa:
- 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 purple bacopa
- 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 purple bacopa care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of purple bacopa 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 purple bacopa
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 purple bacopa — frequently asked questions
What fertiliser does purple bacopa 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. Purple Bacopa 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 purple bacopa?
Apply a comprehensive liquid aquarium fertiliser weekly, ensuring adequate potassium and micronutrients. Iron supplementation (0.1-0.2 ppm) deepens purple pigmentation. Avoid over-fertilising with nitrogen, which shifts colour toward green. Apply a comprehensive liquid aquarium fertiliser weekly, ensuring adequate potassium and micronutrients. Iron supplementation (0.1-0.2 ppm) deepens purple pigmentation. Avoid over-fertilising with nitrogen, which shifts colour toward green. Treat that as weekly 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 purple bacopa?
Half strength is the safe default for purple bacopa — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding purple bacopa 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 purple bacopa 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 purple bacopa?
Flush the pot of purple bacopa 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
- Purple Bacopa care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water purple bacopa — 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 awl-leaved air plant
- How to fertilise forked begonia
- How to fertilise two-petal begonia
- All 11687 fertilising guides in the Growli library