How to Grow Bitter Melon
Momordica charantia
Bitter melon is a heat-loving tropical vine that needs a long warm season. Start seeds indoors 4 weeks before last frost, nicking the seed coat to speed germination. Plant out into rich, well-drained soil once nights are reliably warm (above 15°C). Provide a sturdy trellis — vines can reach 3 m. Pinch tips early to encourage branching. Feed regularly and keep moisture consistent. Harvest fruits young and green for the best flavour; leaving them on the vine too long makes them very bitter and seedy.
When to Start
Start seeds indoors 4 weeks before your last frost date. Transplant outdoors once night temperatures stay above 15°C and soil has warmed to at least 20°C.
Don't know your frost date? Find it here →
Growth Stages
Approximate days from start
Care Essentials
- Feed every two weeks with a balanced liquid fertiliser from planting out; switch to high-potash once fruits begin to set.
- Nick or soak seeds overnight before sowing to improve germination. Harvest fruits while still firm and green — once they turn orange they split open and become too bitter and seedy to eat.
Growing Conditions
- Min. soil temperature
- 20°C+
- Germination temperature
- 24–35°C
- Sow indoors
- —
- Transplant out
- —
- First harvest
- —
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Spacing & Planting
| Plant spacing | 45 cm |
| Row spacing | 90 cm |
| Sow depth | 2 cm |
| Mature height | 300 cm |
| Mature spread | 90 cm |
Vining cucurbit that climbs readily. Space plants 45 cm apart along a trellis or fence. Rows at least 90 cm apart. In small gardens, train single stems vertically up netting to save space.
Pests & Diseases
Pest Aphids
Identification: Clusters of small soft-bodied insects on shoot tips and undersides of leaves; sticky honeydew residue; distorted new growth
- Blast off with a strong jet of water
- Introduce ladybirds or lacewing larvae as biological control
- Spray with insecticidal soap or neem oil solution
- Spray with a pyrethrin-based insecticide as a last resort
Pest Whitefly
Identification: Tiny white-winged insects that fly up in clouds when plants are disturbed; sticky honeydew and sooty mould on leaves
- Hang yellow sticky traps to monitor and reduce populations
- Introduce Encarsia formosa parasitic wasp under glass
- Spray with a fatty acid or plant oil-based insecticide
Pest Red Spider Mite
Identification: Fine pale mottling on upper leaf surfaces; tiny mites and fine webbing on leaf undersides; thrives in hot, dry conditions
- Mist plants regularly to raise humidity
- Introduce Phytoseiulus persimilis as biological control under glass
- Remove and destroy heavily infested leaves
- Spray with a plant oil or fatty acid-based product ensuring good leaf underside coverage
Disease Powdery Mildew
Symptoms: White powdery patches on leaves, spreading to cover large areas; yellowing and premature leaf death
Treatment: Remove badly affected leaves. Apply a fungicide approved for edible crops if severe.
Prevention: Ensure good air circulation, avoid overhead watering, water at soil level. Do not overcrowd plants.
Disease Downy Mildew
Symptoms: Yellow patches on upper leaf surfaces with grey-purple fuzzy growth on the undersides; leaves die back rapidly in wet conditions
Treatment: Remove and destroy affected leaves immediately. Improve ventilation.
Prevention: Water at the base, avoid wetting foliage, space plants well, grow under cover in wet climates.
Growing Conditions
| Min. soil temperature | 20°C |
| Germination temperature | 24–35°C |
| Base growth temperature | 15°C |
| Min. daylength to start | 10.5h |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Bitter Melon?
- Plant Bitter Melon 45cm apart with 90cm between rows.
- When can I harvest Bitter Melon?
- Bitter Melon is ready to harvest approximately 60 days after transplanting.
- Is Bitter Melon frost hardy?
- Bitter Melon is classified as Tender.
