Fertilising guide
How to fertilise Oxalis tetraphylla (Oxalis tetraphylla)— schedule & NPK
Also called four-leaf sorrel, iron cross plant, lucky clover.
More about oxalis tetraphylla
About Oxalis tetraphylla
Oxalis tetraphylla · also called four-leaf sorrel, iron cross plant · flowering
Oxalis tetraphylla is a bulbous wood sorrel grown for its distinctive four-leaflet clover leaves, each marked with a dark purple 'iron cross' band, topped by clusters of small rose-pink flowers in summer. The leaves fold at night and in bright sun. A tender perennial from Mexico, it grows from small bulbs and goes dormant after flowering or in cold conditions.
Growth habit: Low, clumping bulbous perennial forming a tidy mound of long-stalked four-part leaves; spreads slowly by offset bulbs.
Watch for — Leggy, pale leaves: Insufficient light. Move to a brighter spot to firm up growth and restore the dark cross markings.
What fertiliser oxalis tetraphylla actually wants — and why
Oxalis tetraphylla is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.
A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom.
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 oxalis tetraphylla: 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 oxalis tetraphylla, 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 oxalis tetraphylla:
Feed every 3-4 weeks while in active leaf and flower with a balanced or slightly high-potash liquid fertiliser at half strength. Stop feeding once the foliage begins to die back for dormancy. For a hungry bloomer that means feeding regularly — every 3-4 weeks — right through flowering across the main season (spring through early autumn), tapering as blooming ends.
The dormant-season rule matters more than the exact interval: skip feeding entirely when oxalis tetraphylla 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 oxalis tetraphylla
Follow the flowering-feed label rate for oxalis tetraphylla, or half strength if feeding very frequently. These plants genuinely use the nutrients — under-feeding shows up fast as a thin display.
Feeding always goes onto already-damp soil, never dry roots — water oxalis tetraphylla first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the oxalis tetraphylla watering schedule.
Signs you are over-feeding oxalis tetraphylla
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for oxalis tetraphylla:
- Lots of lush leaves but few flowers (too much nitrogen).
- Scorched leaf edges and salt crust from too-strong or too-frequent feeds.
- Soft, sappy growth prone to aphids and mildew.
Signs you are under-feeding oxalis tetraphylla
- Sparse, small, short-lived flowers and pale foliage.
- A tired plant that stops blooming early in the season.
- Weak growth and poor repeat-flowering after the first flush.
If the symptoms point at watering, light or roots rather than nutrition, the full oxalis tetraphylla care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Container-grown oxalis tetraphylla accumulates feed salts fast with frequent feeding — water until it drains each time and flush pots with plain water every few weeks to prevent scorch.
Organic vs synthetic feeds for oxalis tetraphylla
Organic options
A liquid comfrey or seaweed feed (naturally potassium-rich) plus compost or well-rotted manure as a mulch. UK: comfrey feed, organic Tomorite, or rose feed; US: Espoma Rose-tone or Neptune's Harvest. Feeds and improves soil.
Synthetic / liquid feeds
A high-potash flowering feed on a regular cadence — UK: Tomorite (Levington), Phostrogen or a specialist rose feed; US: Miracle-Gro Bloom Booster or a rose food. Fast, reliable bloom response.
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 oxalis tetraphylla — frequently asked questions
What fertiliser does oxalis tetraphylla need?
A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom. Oxalis tetraphylla is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.
How often should I feed oxalis tetraphylla?
Feed every 3-4 weeks while in active leaf and flower with a balanced or slightly high-potash liquid fertiliser at half strength. Stop feeding once the foliage begins to die back for dormancy. Feed every 3-4 weeks while in active leaf and flower with a balanced or slightly high-potash liquid fertiliser at half strength. Stop feeding once the foliage begins to die back for dormancy. For a hungry bloomer that means feeding regularly — every 3-4 weeks — right through flowering across the main season (spring through early autumn), tapering as blooming ends.
What strength of feed for oxalis tetraphylla?
Follow the flowering-feed label rate for oxalis tetraphylla, or half strength if feeding very frequently. These plants genuinely use the nutrients — under-feeding shows up fast as a thin display.
What does over-feeding oxalis tetraphylla look like?
Lots of lush leaves but few flowers (too much nitrogen). Scorched leaf edges and salt crust from too-strong or too-frequent feeds. Soft, sappy growth prone to aphids and mildew. Using a high-nitrogen general feed on oxalis tetraphylla is the headline mistake — you grow a big leafy plant with few flowers. The second is simply under-feeding a genuinely hungry bloomer and getting a sparse, short display.
Should I flush the soil of oxalis tetraphylla?
Container-grown oxalis tetraphylla accumulates feed salts fast with frequent feeding — water until it drains each time and flush pots with plain water every few weeks to prevent scorch.
Keep reading
- Oxalis tetraphylla care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water oxalis tetraphylla — 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 peace lily
- How to fertilise bird of paradise
- How to fertilise hoya
- All 2464 fertilising guides in the Growli library