How to Grow Kumquat
Citrus japonica
Kumquat is the hardiest citrus, tolerating brief frosts to -5°C. Grow in containers with specialist citrus compost and excellent drainage. Place outdoors in full sun from late May to September, then move to a frost-free greenhouse or cool bright room (5-10°C) for winter. Feed every two weeks with citrus fertiliser during the growing season. The fruit is unique — eat the sweet skin and tart flesh together whole.
Yearly Lifecycle
Care Essentials
Citrus fertiliser every 2-4 weeks during the growing season (April-September). Reduce to monthly in winter.
Watch For
- Scale insects
- Mealybug
- Red spider mite
- Leaf drop from overwatering or sudden temperature changes
Companions
Basil, Lavender, Marigolds
Track your Kumquat care schedule — pruning, feeding, and seasonal tasks
Start planning freeCare Requirements
☀️ Light
Full sun; outdoors in summer, brightest spot in winter
Full sun is essential. Place outdoors in the sunniest spot from late May to September. Indoors in winter, choose the brightest south-facing position. Insufficient light causes poor flowering and fruit set.
💧 Watering
Water when top 2cm dry; rainwater preferred; reduce in winter
Water when the top 2cm of compost is dry. Use rainwater where possible as citrus dislike hard tap water. Reduce significantly in winter — only water to prevent complete drying. Never let the pot sit in water.
🌱 Fertilizing
Citrus fertiliser every 2-4 weeks April-September
Feed every two to four weeks with specialist citrus fertiliser during the growing season (April to September). Reduce to monthly or stop in winter. Kumquats are heavy feeders when in active growth.
✂️ Pruning
Minimal pruning in late winter; remove dead wood only
Minimal pruning needed. Remove dead or crossing branches in late winter before new growth. Pinch shoot tips lightly to maintain shape. Avoid heavy pruning which delays fruiting.
❄️ Overwintering
Frost-free over winter; cool bright room at 5-10°C
Hardy to about -5°C but prolonged frost damages wood and fruit. In the UK, move containers to a frost-free greenhouse or cool bright room (5-10°C) from November. Avoid warm centrally heated rooms.
Growing Tips
Eat the whole fruit
Unlike other citrus, kumquats are eaten whole — the thin skin is sweet and the flesh is tart. Roll between your fingers to release the oils before eating for the best flavour.
Rainwater and good drainage
Use rainwater where possible as kumquats dislike the lime in hard tap water. Water when the top 2cm of compost feels dry and never let pots sit in water.
Feed through the season
Feed every two to four weeks with specialist citrus fertiliser from April to September. Yellowing leaves between veins often signal magnesium or nitrogen deficiency — use a chelated citrus feed.
Hardy but not bulletproof
Kumquats tolerate brief frosts to -5°C but prolonged freezing kills fruit and damages wood. Protect containers by moving them under cover before hard frosts are forecast.
Pests & Diseases
Pest Scale Insects
Identification: Small brown or white waxy bumps on stems and leaf undersides; sticky honeydew and sooty mould
- Wipe off with a damp cloth or cotton bud dipped in methylated spirit
- Spray with plant oil-based winter wash when dormant
- Apply systemic insecticide containing acetamiprid in spring
Pest Mealybug
Identification: White cottony masses in leaf axils and on stems; sticky honeydew and sooty mould
- Dab with methylated spirit on a cotton bud
- Introduce Cryptolaemus montrouzieri ladybird as biological control
- Spray with fatty acid-based insecticide ensuring good coverage of hidden areas
Pest Red Spider Mite
Identification: Fine webbing on leaf undersides; leaves develop pale stippling and may bronze and drop
- Mist foliage regularly to raise humidity
- Introduce Phytoseiulus persimilis predatory mites
- Spray with plant oil-based miticide repeating every 7 days
Disease Root Rot Phytophthora spp.
Symptoms: Yellowing leaves, wilting despite wet compost, dark mushy roots; tree declines and may die
Treatment: Repot into fresh free-draining citrus compost; trim away rotten roots; reduce watering
Prevention: Use well-draining compost with added perlite; never let pots sit in water; water only when top 2cm is dry
Disease Sooty Mould Capnodium spp.
Symptoms: Black powdery coating on leaves and stems, growing on honeydew from sap-sucking insects
Treatment: Wipe leaves clean with a damp cloth; control the underlying pest (scale, mealybug, or whitefly)
Prevention: Monitor and treat sap-sucking pests promptly; improve ventilation around the plant
Popular Varieties
Nagami, Marumi, Meiwa, Centennial Variegated
Spacing & Planting
| Plant spacing | 250 cm |
| Row spacing | 300 cm |
| Mature height | 250 cm |
| Mature spread | 200 cm |
Container 1.5-2m between pots. In-ground 2.5-3m apart. Dwarf varieties can be grown in 40-50cm diameter pots.
Log Kumquat in your garden — track growth, care, and harvests year after year
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