How to Grow Black Seeded Yard Long Bean
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Black Seeded Yard Long Bean
Vigna unguiculata subsp. sesquipedalis
vegetableYard long beans, also called asparagus beans, are a tropical legume that produces exceptionally long, slender green pods reaching 12-18 inches or more. These tender beans are prized in Asian cuisine for their crisp texture and mild, slightly sweet flavor. The black seeded variety is particularly popular for its productivity and flavor.
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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 →Thrives in zones 9-11; can be grown as an annual in zones 8-8b with warm-season planting
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Germination & Seedling
1-2 weeksSeeds sprout within 7-10 days; cotyledons emerge and first true leaves appear
Keep soil warm (70-80°F is ideal); maintain consistent moisture; provide bright light once sprouted. Thin seedlings to proper spacing if direct sowing.
Vegetative Growth
3-4 weeksPlant develops vigorous vining growth with compound leaves; climbing or twining tendrils emerge
Provide sturdy trellis, fence, or pole support immediately; tie loosely as vines climb. Water regularly and maintain warm temperatures (75-85°F). Apply balanced fertilizer every 2-3 weeks.
Flowering
2-3 weeksPlant produces small, delicate white, pink, or purple flowers in clusters along the vine
Ensure consistent watering and warmth; reduce nitrogen fertilizer slightly to favor flowering over excessive foliage. Flowers may drop in extreme heat; evening watering helps.
Pod Development & Elongation
3-5 weeksThin, long pods develop from flowers and rapidly elongate, reaching 12-18+ inches
Continue regular watering and light feeding with balanced or slightly higher potassium fertilizer. Pick pods regularly to encourage continuous production. Provide consistent warmth.
Harvest
Ongoing for 6-8 weeksPods reach full length and optimal tenderness; seeds inside remain small and immature
Harvest every 2-3 days for best texture and to encourage more flowering. Wear gloves to protect skin. Pods left too long become tough and fibrous.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Hand-pick in early morning; use neem oil or insecticidal soap; plant trap crops like nasturtium nearby
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Strong water spray to dislodge; spray with neem oil or insecticidal soap; encourage beneficial insects like ladybugs
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Yellow sticky traps; spray with neem oil or horticultural oil; ensure good air circulation
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Increase humidity; spray with water; use neem oil or miticide if severe; avoid high heat stress
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Remove infested pods immediately; use pheromone traps; apply neem oil preventatively
Uses
Stir-fries & Asian Cuisine
CulinaryYard long beans are a staple in Asian cooking, prized for their tender, crisp texture and mild flavor. They cook quickly and retain their crunch, making them ideal for stir-fries, curries, and steamed dishes. [source]
Fresh Preparation
CulinaryCan be blanched and cooled for salads, steamed as a side dish, or sautéed with garlic and oil. Their asparagus-like texture makes them versatile for any cooking method. [source]
Nutritional Benefits
MedicinalHigh in vitamin C, vitamin A, fiber, and plant-based protein. Also contains polyphenols and antioxidants that support overall health and may aid digestion. [source]
Nitrogen Fixation
HouseholdAs a legume, yard long beans fix nitrogen from the air into the soil via symbiotic bacteria, enriching soil fertility for subsequent plantings without synthetic fertilizers. [source]
Garden Pollinators
WildlifeDelicate flowers attract bees, butterflies, and other beneficial pollinators, supporting overall garden ecosystem health and biodiversity. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Begin harvesting when pods are 8-12 inches long and still tender, typically 50-60 days after planting. Pick every 2-3 days to maintain pod tenderness and encourage continuous production. Pods left too long become tough, fibrous, and woody. Harvest in early morning when pods are crisp. Use a gentle twisting motion to remove pods without damaging the vine. Continue harvesting until frost (in cold zones) or as long as flowers keep producing (in warm zones).
Fun Facts
- 🌱 Yard long beans earned their name because mature pods can stretch beyond 12 inches, resembling a yard in length—though they're best eaten long before maturity.
- 🌱 Unlike common bush beans, yard long beans are strictly tropical vining plants that require warm temperatures year-round and cannot tolerate frost or cold snaps.
- 🌱 In traditional Chinese medicine, yard long beans are believed to support kidney and digestive health and are often included in healing soups and broths.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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