How to Grow Grapefruit
Citrus paradisi
Grapefruit needs more warmth than most citrus and must be grown under glass in the UK — a heated greenhouse or bright conservatory is ideal. Grow in a large container of loam-based compost with added grit, feed with citrus fertiliser every two to four weeks during the growing season, and reduce watering in winter. Move outdoors to a sunny, sheltered patio from June to September, then bring back inside before the first frost. Prune lightly in spring to remove dead wood and shape.
Yearly Lifecycle
Care Essentials
Citrus fertiliser every 2–4 weeks during the growing season. Reduce in winter.
Watch For
- Scale insects
- Mealybug
- Red spider mite
- Leaf drop
Companions
Basil, Lavender, Marigolds
Track your Grapefruit care schedule — pruning, feeding, and seasonal tasks
Start planning freeCare Requirements
☀️ Light
Brightest position possible, south-facing ideal
Needs the brightest position available. A south-facing conservatory or heated greenhouse is ideal. Move outdoors to a sunny, sheltered patio from June to September.
💧 Watering
Free watering in summer, reduced but consistent in winter
Water freely in summer, allowing the top few centimetres to dry between waterings. Reduce in winter but never let the compost dry out completely. Use rainwater if possible.
🌱 Fertilizing
Citrus fertiliser every 2-4 weeks, spring to autumn
Feed with a specialist citrus fertiliser every two to four weeks from spring to autumn. Reduce to monthly in winter. Citrus are hungry plants that yellow without regular feeding.
✂️ Pruning
Light spring pruning, remove dead wood and suckers
Prune lightly in spring to remove dead wood, crossing branches, and to shape. Grapefruit needs minimal pruning. Remove any suckers from below the graft union.
❄️ Overwintering
Indoors before frost, bright room above 10°C
Bring indoors before the first frost to a bright room kept above 10°C. Grapefruit is less cold-tolerant than lemons and needs consistent warmth through winter.
Growing Tips
Warmth and light are key
Grapefruit needs consistent warmth. Keep above 10°C in winter and provide the brightest position you can — a south-facing conservatory is ideal.
Feed regularly with citrus fertiliser
Use a specialist citrus feed every two to four weeks from spring to autumn. Cut back to monthly in winter.
Summer outdoors, winter indoors
Move the pot outdoors to a sunny, sheltered spot from June to September. The summer warmth and light improve fruit quality.
Check for pests under glass
Watch for scale insects, mealybug, and red spider mite — common under glass. Wipe leaves and treat early.
Pests & Diseases
Pest Scale Insects
Identification: Small brown or white bumps on stems and leaf undersides, sticky honeydew and sooty mould
- Wipe off with a cloth dipped in soapy water
- Introduce parasitic wasps (Metaphycus helvolus) as biological control under glass
- Apply plant oil-based winter wash to dormant stems
Pest Mealybug
Identification: White cottony masses in leaf axils and on stems, sticky honeydew
- Dab with a cotton bud soaked in methylated spirit
- Introduce Cryptolaemus ladybird as biological control
- Spray with fatty acid or plant oil-based insecticide
Pest Red Spider Mite
Identification: Fine webbing on leaf undersides, stippled yellowing leaves, tiny mites visible with a hand lens
- Increase humidity by misting regularly
- Introduce predatory mite Phytoseiulus persimilis
- Spray with fatty acid-based miticide
Disease Citrus Canker Xanthomonas citri
Symptoms: Raised corky lesions on leaves, stems, and fruit with a water-soaked margin and yellow halo
Treatment: Remove and destroy affected growth. Isolate the plant from other citrus
Prevention: Buy certified disease-free stock. Avoid overhead watering. Disinfect tools between plants
Disease Sooty Mould
Symptoms: Black powdery coating on leaves and fruit, growing on honeydew from sap-sucking insects
Treatment: Wipe off with a damp cloth. Control the underlying pest problem (scale, mealybug, or aphids)
Prevention: Monitor for and control sap-sucking pests promptly
Disease Root Rot Phytophthora spp.
Symptoms: Yellowing leaves, leaf drop, wilting despite moist soil, dark mushy roots
Treatment: Remove from pot, trim rotten roots, repot in fresh free-draining compost. Reduce watering
Prevention: Use loam-based compost with added grit. Ensure pots have good drainage. Water only when top few cm are dry
Popular Varieties
Ruby Red, Star Ruby, Marsh, Duncan, Oro Blanco
Spacing & Planting
| Plant spacing | 500 cm |
| Row spacing | 550 cm |
| Mature height | 500 cm |
| Mature spread | 400 cm |
Standard trees need 5-6m spacing. Semi-dwarf 4-5m. Larger than other citrus.
Log Grapefruit in your garden — track growth, care, and harvests year after year
Start planning free