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How to Grow Yard-Long Bean

Vigna unguiculata subsp. sesquipedalis

Tender Warm Season Continuous Harvest

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

Sow seeds
Germination ~8d
Flowering ~50d
Fruiting ~60d
Harvest ~70d

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.

Companion Planting

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Growing Conditions

Min. soil temperature: 16°C+
Germination temperature: 18–30°C

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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.

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Care Guide

Feeding
Rarely needed — they fix their own nitrogen. Apply a balanced liquid feed once pods start setting if growth looks slow.
Watch for
  • Aphids on shoot tips
  • Slugs on young plants
  • Powdery mildew in humid conditions
  • Bean fly (in warm climates)

Pests & Diseases

Pest Aphids

Identification: Clusters of small insects on shoot tips and flower stems; sticky honeydew; distorted growth

Organic treatment:
  • Pinch out heavily infested shoot tips
  • Spray with insecticidal soap or diluted neem oil
  • Encourage ladybirds and lacewings
Chemical treatment:
  • 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

Organic treatment:
  • Apply ferric phosphate slug pellets around seedlings
  • Hand-pick at dusk; use beer traps
  • Protect individual plants with cut plastic bottles
Chemical treatment:
  • 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 temperature16°C
Germination temperature18–30°C
Base growth temperature12°C
Min. daylength to start10.5h
Photoperiod sensitivityday 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.

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