How to Grow Black-Seeded Yard Long Bean
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Black-Seeded Yard Long Bean
Vigna unguiculata subsp. sesquipedalis
vegetableA long-podded legume originating from Asia, producing slender pods that can reach 12-24 inches in length. The black seeds distinguish this variety from other yard long beans and offer a rich flavor profile. These vining plants are prolific producers and thrive in warm, tropical to subtropical climates.
When should you plant Black-Seeded Yard Long Bean in your zone?
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Example Black-Seeded Yard Long Bean timeline · Pittsburgh, PA (Zone 6b)
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Plant Black-Seeded Yard Long Bean
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Black-Seeded Yard Long Bean
Around Jun 16≈ 60 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Black-Seeded Yard Long Bean dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Zones 9-11; grown as warm-season annual in zones 6-8
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Seedling
1-2 weeksEmerging cotyledons and first true leaves appear within 7-10 days
Keep soil consistently moist but not waterlogged. Provide bright light. Thin seedlings to proper spacing once they have 2-3 true leaves.
Flowering
2-3 weeksSmall white, pink, or purple flowers appear in clusters along the vines
Maintain consistent watering and warmth (above 65°F). Reduce nitrogen to encourage flowering rather than excess foliage. High temperatures promote flower production.
Pod Development
2-3 weeksPods elongate rapidly, reaching characteristic 12-24 inch length with developing black seeds inside
Continue regular watering and maintain warm temperatures. Support heavy pod loads with additional ties. Monitor for pests as young pods are vulnerable.
Harvest Ready
4-8 weeks continuousPods reach full length with tender texture; seeds visible but not fully mature for dry bean harvest
Pick pods regularly to encourage continued production. Harvest young for tender eating or allow full maturation for dry beans.
Common Pests
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Hand-pick early morning; use neem oil spray; plant companion marigolds; row covers on young plants
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Spray with insecticidal soap; yellow sticky traps; encourage beneficial insects; spray with water to dislodge
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Strong water spray; neem oil; insecticidal soap; attract ladybugs with flowering plants
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Monitor regularly; remove affected pods; use Bt (Bacillus thuringiensis); encourage parasitic wasps
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Increase humidity with regular misting; spray with water; neem oil; introduce predatory mites
Uses
Tender pod vegetable
CulinaryYoung pods can be stir-fried, steamed, boiled, or used in soups with a slightly sweet, tender texture. Both pod and seeds are edible when harvested young. [source]
Dry bean storage
CulinaryMature black seeds can be dried and stored for months, then cooked like black beans in curries, soups, and stews. Black-seeded varieties have richer flavor than other yard long bean colors. [source]
Nutritional support
MedicinalRich in protein, fiber, and antioxidants. Traditional Asian medicine uses yard long beans for digestive support and vitality. High in iron and folate, particularly beneficial in plant-based diets. [source]
Nitrogen fixation
HouseholdAs a legume, yard long beans fix nitrogen in soil through symbiotic relationship with rhizobia bacteria, naturally enriching garden beds and reducing fertilizer needs for subsequent crops. [source]
Pollinator support
WildlifeFlowers attract bees, butterflies, and other beneficial pollinators while providing nectar and pollen sources during warm growing season. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
For tender eating: pick pods when 6-8 inches long and tender, before seeds bulge (approximately 50-60 days from planting). For mature dry beans: allow pods to remain on vine until fully brown and dry (100+ days), then harvest, dry further indoors, and shell. Harvest young pods regularly to encourage continued flowering and production. Early morning harvest provides maximum crispness.
Fun Facts
- 🌱 Yard long beans can grow up to 24 inches in a single day during peak growing season, earning them the nickname 'asparagus bean' for their slender profile.
- 🌱 The black seed variety originated in Asia and is particularly popular in Thai and Vietnamese cuisines, where the tender pods are a staple ingredient.
- 🌱 Unlike common beans, yard long beans thrive in intense heat and humidity, making them ideal for tropical and subtropical gardeners who struggle with traditional snap beans.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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