How to Grow Japanese Long Green Cucumber
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Japanese Long Green Cucumber
Cucumis sativus var. longus
vegetableJapanese Long Green is a slicing cucumber variety that produces long, thin, seedless fruits typically 12-14 inches in length with thin skin and few bumps. This Asian cucumber variety is prized for its crisp texture, mild flavor, and tender skin that doesn't require peeling. It's ideal for fresh eating, salads, and sushi preparation.
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Example Japanese Long Green Cucumber timeline · Pittsburgh, PA (Zone 6b)
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Plant Japanese Long Green Cucumber
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 Japanese Long Green Cucumber
Around Jun 6≈ 50 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Japanese Long Green Cucumber dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 5-9; can be grown as summer annual in zones 3-4
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Get my Japanese Long Green Cucumber timeline →Growth Stages
Germination & Seedling
2-3 weeksSeeds sprout in 7-10 days in warm soil (70-80°F). True leaves develop after cotyledons.
Maintain warm soil temperature. Keep soil consistently moist. Thin seedlings or transplant when 2-3 true leaves appear. Provide bright light if starting indoors.
Vegetative Growth
2-3 weeksPlant develops multiple stems, tendrils, and large lobed leaves. Growth is vigorous if conditions are optimal.
Install trellises or stakes early. Train vines onto support structure for better air circulation and fruit quality. Fertilize every 2-3 weeks with balanced fertilizer. Pinch off side shoots if desired for tidier training.
Flowering
2-3 weeksBright yellow flowers appear at leaf axils. Separate male and female flowers are produced (female flowers have tiny fruit behind the bloom).
Ensure adequate pollination—bees typically handle this, but hand-pollinate if needed. Maintain consistent watering and moderate nitrogen to support flowering. Do not overwater, which delays flowering.
Fruit Development & Elongation
2-3 weeksFruits develop rapidly after pollination, elongating to characteristic 12-14 inch length. Fruits remain light green, slender, and mostly seedless.
Maintain even watering to prevent bitter fruit and splitting. Continue regular fertilization. Support heavy fruits with slings if needed. Monitor for pests and diseases. Harvest immature fruits to encourage continued production.
Harvest & Production
4-8 weeksFruits reach full length and remain tender. Plant continues producing new flowers and fruits if harvested regularly.
Pick fruits every 2-3 days to encourage more blooms. Harvest when cucumbers are 12-14 inches long and firm. Use sharp scissors or pruning shears to avoid damaging vines. Plants typically produce for 6-8 weeks.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Row covers until flowering, yellow sticky traps, neem oil spray, hand-picking. Plant resistant varieties or use reflective mulch.
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Improve air circulation, avoid overhead watering, spray with sulfur or potassium bicarbonate. Remove affected leaves.
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Remove infected leaves promptly, use copper fungicide, improve drainage and air circulation, avoid wetting foliage.
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Increase humidity, spray with water jet, use insecticidal soap or neem oil, introduce predatory mites.
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Strong water spray, insecticidal soap, neem oil, encourage beneficial insects like ladybugs.
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Control aphid vectors with neem oil, remove and destroy infected plants, keep area weed-free, plant resistant varieties.
Uses
Fresh eating and salads
CulinaryJapanese Long Green cucumbers are exceptional for fresh consumption due to their thin, tender, seedless skin that requires no peeling and their crisp, refreshing texture. They are ideal for salads, sushi rolls, and Asian cuisine. [source]
Pickling and preserves
CulinaryThe slender shape and thin skin make these cucumbers excellent for quick pickling, lacto-fermentation, and Asian pickle preparations that retain their crispness. [source]
Sushi and Asian cuisine
CulinaryThese cucumbers are specifically bred for Japanese cuisine and are a traditional ingredient in sushi rolls (kappamaki), sunomono (vinegar salads), and other Asian dishes where their delicate form and mild flavor enhance the final dish. [source]
Skin care and facial treatments
HouseholdCucumber slices and cucumber water are traditionally used for facial hydration, reducing puffiness, and soothing irritated skin due to their high water content and silica. [source]
Pollinator attraction
WildlifeThe bright yellow cucumber flowers attract bees, butterflies, and other pollinators, supporting garden biodiversity and ecosystem health while improving fruit set. [source]
Harvest Tips
Harvest when cucumbers reach 12-14 inches in length, while still dark green and firm. Pick every 2-3 days during peak season to encourage continuous fruiting. Use a sharp knife or pruning shears to cut the stem 1-2 inches above the fruit to avoid damaging the vine. Early morning harvest yields crispest fruits. Fruits can be eaten fresh with skin on or used immediately for best quality and flavor.
Fun Facts
- 🌱 Japanese Long Green cucumbers are nearly seedless because they are primarily produced through the flower's female parts with minimal seed development, making them more pleasant to eat fresh without removal of large seed cavities.
- 🌱 These cucumbers are also called 'Suyo Long' or 'Asian Long Cucumbers' and have been cultivated in Japan and Asia for centuries, becoming a staple in Japanese and Chinese cuisine long before becoming popular in Western gardens.
- 🌱 Unlike many cucumber varieties, Japanese Long Green cucumbers develop their sweetest flavor and most tender skin when harvested young and small (10-14 inches), as the fruit can become tough and bitter if left to grow too large.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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