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How to Grow Yard Long Bean, Chinese Purple

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Yard Long Bean, Chinese Purple

Vigna unguiculata subsp. sesquipedalis

vegetable

Yard long beans (also called asparagus beans) are a vigorous climbing vine producing slender, purple pods that can reach 12-18 inches in length. These tender beans are staple vegetables in Asian cuisine, with a slightly sweeter flavor and more delicate texture than snap beans. The purple variety develops deep purple coloring at maturity and turns greenish when cooked.

Looking for a specific variety?

Chinese Purple Thai Purple Red Noodle Mosaic Yard Long White Asparagus Bean Green

When should you plant Yard Long Bean, Chinese Purple in your zone?

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Example Yard Long Bean, Chinese Purple timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Yard Long Bean, Chinese Purple

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Yard Long Bean, Chinese Purple

    Around Jun 16

    ≈ 60 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Yard Long Bean, Chinese Purple dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 6-8 hours daily; prefers afternoon shade in very hot climates
💧
Water: Keep soil consistently moist but not waterlogged; water deeply 1-2 times per week depending on rainfall. Drought-tolerant once established but produces better yields with regular watering.
📏
Spacing: 6 inches
📅
Days to maturity: 60-80 days from planting to first harvest
🌱
Planting depth: 1-1.5 inches

Soil

Type: Well-draining loamy soil rich in organic matter
pH: 6.0-7.0
Amendments:
Compost aged manure peat moss or coconut coir

Growing Zones

Find your zone →

Thrives in zones 6-11; can be grown as an annual in zone 5

5b 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b 11a

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Growth Stages

1

Germination & Seedling

2-3 weeks

Seeds sprout within 7-14 days. Seedlings develop two cotyledons followed by true leaves with characteristic oval leaflets.

Maintain warm soil (65-75°F). Keep soil moist but not soggy. Thin seedlings to proper spacing. Provide support structure early if direct seeding.

2

Vine Development

3-4 weeks

Plant produces climbing vines with compound leaves and becomes bushy. Vines climb steadily upward along supports, developing 3-5 foot tall growth.

Ensure sturdy trellising or supports (6-8 feet tall recommended). Train vines upward. Fertilize every 2-3 weeks with balanced or slightly nitrogen-rich fertilizer. Water consistently.

3

Flowering

2-3 weeks

Purple or white flowers appear in clusters along the vine. Flowers are typically small and inconspicuous but prolific.

Continue watering and fertilizing (switch to lower nitrogen at this stage). Ensure adequate pollinator access. Thin foliage slightly if shading developing flowers excessively.

4

Pod Development & Maturation

3-4 weeks

Small pod primordia develop into long, slender purple beans. Pods can reach 12-18 inches long. Deep purple color intensifies as pods mature.

Water regularly, especially during pod fill. Maintain mulch to retain moisture and keep soil cool. Monitor for pests. Do not allow plants to dry out.

5

Harvest

4-6 weeks continuous harvest

Pods reach full length and firm texture. Purple color is deepest. Tender young pods are ready for picking.

Harvest regularly every 2-3 days when pods are 8-12 inches long for peak tenderness. Pick before they become overmature. Wear gloves as vines can be prickly.

Companion Planting

Plan your garden →

Plant with:

Corn Basil Marigold Nasturtium Garlic Onion Pumpkin Squash Radish

Avoid planting near:

Fennel Kohlrabi Cabbage Broccoli Cauliflower Onion (if using as nitrogen-fixing cover crop)

Common Pests

  • Spray with water to dislodge; use insecticidal soap or neem oil; increase humidity; introduce predatory mites.

  • Use row covers during early growth; harvest promptly; store dry beans in sealed containers with diatomaceous earth.

  • Use yellow sticky traps; spray with neem oil or insecticidal soap; introduce parasitic wasps.

  • Spray with strong water stream; use insecticidal soap; apply neem oil; encourage natural predators like ladybugs.

  • Hand-pick beetles and egg clusters; use neem oil; apply spinosad; use row covers on young plants.

Uses

🍳

Stir-fries and Asian cuisine

Culinary

Chinese purple yard long beans are a staple in Asian cooking, prized for their delicate texture and slightly sweet flavor when cooked. They are perfect for stir-frying with garlic, sesame oil, and soy sauce. [source]

🍳

Fresh vegetable dishes

Culinary

Tender young pods can be blanched, steamed, boiled, or eaten raw in salads. Purple color converts to green when cooked but maintains excellent texture. [source]

🏠

Nitrogen fixation & soil improvement

Household

As a legume, yard long beans fix atmospheric nitrogen in the soil through nodule-forming bacteria (Rhizobium), improving soil fertility for subsequent crops. Work plant residues into soil after harvest. [source]

🍳

Dried bean storage

Culinary

Mature, fully-dried pods can be shelled to harvest dried beans suitable for long-term storage and cooking. These dried beans are nutrient-dense and provide sustainable food supply. [source]

🦋

Pollinator and beneficial insect support

Wildlife

The prolific flowers attract bees, butterflies, and other pollinators. The dense vine growth provides habitat for beneficial insects that control garden pests. [source]

Harvest Tips

Begin harvesting when pods reach 8-12 inches long and are still tender; they turn tough and stringy if left too long. Harvest every 2-3 days to encourage continuous production. Pick in the morning when cooler. Use gentle twisting motion or small shears to avoid damaging vines. Mature pods (15-18 inches) can be left to dry on the vine for shelling and saving seeds. Flavor is optimal when pods are tender and snap easily.

Fun Facts

  • 🌱 Yard long beans earned their name because pods can grow up to 18 inches (about one yard) long, making them significantly longer than typical snap beans.
  • 🌱 In traditional Asian agriculture, yard long beans are sometimes intercropped with corn using the 'three sisters' concept, where the bean vines climb the corn stalks while fixing nitrogen and beans provide shade.
  • 🌱 The purple variety turns bright green when cooked, revealing the tender interior while the pigmentation (from anthocyanins) remains in the skin but becomes less visually prominent.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Full Sun Mulch Trellis True Leaves
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