Yardlong Bean / Snake Bean

Vigna unguiculata subsp. sesquipedalis

Crop overview

Crop group: Legume
Lifecycle: Annual
Growth habit: Vigorous Heat-Loving Twining Vine With Long Edible Pods

This profile covers climbing cultivars of Vigna unguiculata subsp. sesquipedalis grown vertically for their tender immature pods. These beans are also commonly called snake beans, asparagus beans, Chinese long beans and long-podded cowpeas. It does not cover bush or dwarf yardlong-bean cultivars, ordinary pole snap beans, shelling cowpeas or other climbing bean species. Follow cultivar-specific guidance where pod length, maturity or day-length response differs. It does not cover ordinary common pole beans, bush cowpeas, black-eyed peas, winged beans, hyacinth beans or dwarf yardlong cultivars that do not require a full trellis. Pod length, colour and ideal harvest size vary considerably between cultivars.

Variety examples

Bia-long, Orient Wonder, Red Noodle, Python

Quick facts

Plant spacing: 15 cm – 30 cm
Row spacing: 90 cm
Support height: 1.80 m – 2.40 m
Support strength: Medium
Support types: Trellis Netting, Wire Trellis, Sturdy Fence, Bean Teepee, String Trellis, Garden Arch
Training method: Twining
Vertical suitability: Recommended
Sun requirement: Full Sun
Days to harvest: 50–80 days

Support & training

Training requirements

Install the support before sowing. Guide young vines toward vertical strings, poles, wire or trellis mesh until they begin twining around the structure. Redirect shoots across unused trellis space as they grow. Keep the long hanging pods clear of the ground and prevent them from becoming trapped or bent within narrow mesh.

Pruning requirements

Routine pruning is generally unnecessary. Redirect tangled or wandering shoots and remove damaged, diseased or severely crowded growth where needed. Avoid heavy pruning during flowering and pod production. Frequent harvesting is more important than pruning for encouraging continued flowering and tender pod production.

Growing setup guidance

Container

Minimum size: 30 L

Plants per container: 2

Grow up to two plants in a broad, stable container holding at least 30 L (about 8 US gal) of potting mix. A larger container provides more stable moisture during very hot weather. Provide excellent drainage and a firmly anchored trellis at planting time. Keep the potting mix consistently moist during flowering and pod development, but do not leave it waterlogged. Containers may require daily moisture checks during hot or windy weather. Feed moderately rather than applying excessive nitrogen, which can encourage leafy growth at the expense of pods.

Raised bed

Sow beside an installed trellis. Raised beds are particularly useful in humid or high-rainfall climates because snake beans are sensitive to waterlogging. Keep the soil evenly moist during flowering and pod development. Leave clear access for frequent harvesting because pods can pass rapidly from tender to tough during hot weather.

In-ground

Direct sow into warm, fertile and freely draining soil beside a completed support. Incorporate organic matter where the soil is poor, but avoid excessive nitrogen fertiliser. As a legume, yardlong bean can form nitrogen-fixing root nodules when compatible Rhizobium bacteria are present. It still requires adequate phosphorus, potassium and other nutrients. Avoid low ground where water remains around the roots after heavy rain.

Planting, pollination & harvest

Sowing / transplanting

Direct sow after frost danger has passed when the soil and nights are thoroughly warm. Cold, wet soil can cause seed to rot or produce very slow growth. Sow seed approximately 2.5 cm (1 in) deep, or follow the cultivar packet where its recommendation differs. Install the support at sowing time so the roots are not disturbed later. Direct sowing is usually preferable. Where the warm season is short, seedlings may be started in individual pots about 2–3 weeks before planting out and transplanted carefully with minimal root disturbance.

Pollination

Yardlong-bean flowers are pollinated primarily through bee and other insect activity. Allow pollinators access to the flowers and avoid applying insecticides while flowers are open and bees are active. Periods of low pollinator activity, extreme heat, heavy rain or water stress may reduce pod set. Where flowers repeatedly fail to form pods, check moisture, temperature and pollinator access before assuming the plant requires additional fertiliser.

Warnings

Yardlong bean is extremely frost-tender and requires warm soil and warm air. Cool conditions sharply slow growth, and pods may suffer chilling injury at temperatures well above freezing. Avoid prolonged waterlogging. Watch for aphids, thrips, mites, bean flies, leafrollers, pod-boring caterpillars, cutworms, root-knot nematodes, rusts, powdery mildew, fungal leaf diseases and bean viruses. Pods pass quickly from tender to tough, fibrous and swollen during hot weather. Harvest regularly rather than waiting for them to reach their maximum possible length. Allowing mature pods to shed seed may result in volunteer seedlings in warm climates.

General notes

Harvest pods while they are long, flexible, crisp and relatively smooth, before the seeds become prominently swollen and the pod becomes tight, constricted or tough. Many cultivars are at their best around 25–45 cm long, even though mature pods may grow considerably longer. The correct harvest size depends on the cultivar, so tenderness and seed development are more reliable guides than length alone. Pick at least two or three times each week and preferably daily during very hot, productive weather. Hold the flower stem or vine while harvesting to avoid tearing it from the support. Young pods are used similarly to green beans. Overmature pods may sometimes be allowed to develop for shelled or dry seed, but that harvest stage is outside the main scope of this profile.

Climate guidance

Choose a climate

Climate suitability: Recommended

Planting season

Plant in late spring after frost danger has passed and both soil and nights are reliably warm. The main crop normally develops during hot summer weather.

Wet / dry season

Water deeply and consistently during flowering and pod growth. Avoid repeated swings between drought and saturated soil.

Soil temperature

Direct sow once soil is at least about 18°C (65°F), with warmer soil encouraging faster emergence and stronger growth.

Frost sensitivity

Extremely frost-tender. Treat the crop as an annual and harvest all usable pods before autumn frost.

Heat sensitivity

Hot summers generally suit yardlong beans better than ordinary snap beans. Extreme heat combined with dry soil may temporarily reduce flowering or cause young pods to abort.

Humidity / disease

Hot, humid or rainy periods can encourage rust, mildew, fungal leaf disease, aphids and mites. Maintain airflow and avoid waterlogging.

Sowing guidance

Direct sow beside the installed support after the soil warms. A second sowing may extend harvest where the hot season is long enough.

Notes

Pods develop very quickly during peak summer heat and may need daily harvesting. Do not wait for them to reach their maximum possible length.

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