How to Grow Yard-Long Bean
Vigna unguiculata subsp. sesquipedalis
Yard-long beans are heat-loving climbers for full sun and fertile, well-drained soil. Erect tall supports (2.5 m+) before planting and sow only when soil exceeds 16°C. Unlike runner beans, they thrive in warm weather — no flower drop in the heat. Keep watering consistent, especially once pods start forming. Pick every 2–3 days when pods are 30–50 cm and still tender; leaving any to mature shuts down flowering completely.
When to Start
Start seeds indoors 3 weeks before your last frost date. Transplant outdoors once night temperatures stay above 12°C and soil has warmed to at least 16°C.
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Growth Stages
Approximate days from start
Care Essentials
- Rarely needed — they fix their own nitrogen. Apply a balanced liquid feed once pods start setting if growth looks slow.
- Yard-long beans thrive in heat — unlike runner beans, warm temperatures improve flower set. They need very tall supports (2.5 m+) and consistent moisture. Soak seeds overnight before sowing for faster germination.
Growing Conditions
- Min. soil temperature
- 16°C+
- Germination temperature
- 18–30°C
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- Sow indoors
- —
- Transplant out
- —
- First harvest
- —
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Spacing & Planting
| Plant spacing | 15 cm |
| Row spacing | 50 cm |
| Sow depth | 3 cm |
| Mature height | 300 cm |
| Mature spread | 30 cm |
Space seeds or transplants at the base of a tall support structure (at least 2.5 m). Row spacing is the gap between support rows.
Pests & Diseases
Pest Aphids
Identification: Clusters of small insects on shoot tips and flower stems; sticky honeydew; distorted growth
- Pinch out heavily infested shoot tips
- Spray with insecticidal soap or diluted neem oil
- Encourage ladybirds and lacewings
- Spray with a contact insecticide containing pyrethrins; avoid open flowers
Pest Slugs and Snails
Identification: Seedlings eaten at ground level overnight; ragged holes in young leaves; slime trails
- Apply ferric phosphate slug pellets around seedlings
- Hand-pick at dusk; use beer traps
- Protect individual plants with cut plastic bottles
- Apply ferric phosphate slug pellets around vulnerable plants
Disease Powdery Mildew Erysiphe polygoni
Symptoms: White powdery coating on leaves and stems, especially in humid conditions or crowded plantings
Treatment: Remove affected leaves; improve air circulation; apply a sulphur-based fungicide if severe
Prevention: Space plants well; avoid overhead watering; water at the base in the morning
Disease Bean Rust Uromyces vignae
Symptoms: Small orange-brown raised pustules on leaves and stems; premature leaf drop in severe cases
Treatment: Remove badly affected leaves; improve airflow; apply sulphur fungicide
Prevention: Ensure good spacing; avoid wetting foliage; rotate crops annually; clear debris at season end
Growing Conditions
| Min. soil temperature | 16°C |
| Germination temperature | 18–30°C |
| Base growth temperature | 12°C |
| Min. daylength to start | 10.5h |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Yard-Long Bean?
- Plant Yard-Long Bean 15cm apart with 50cm between rows.
- When can I harvest Yard-Long Bean?
- Yard-Long Bean is ready to harvest approximately 55 days after transplanting.
- Is Yard-Long Bean frost hardy?
- Yard-Long Bean is classified as Tender.
