Sweetest EVER Japanese Cucumber Seeds, Jibai Shimoshirazu

(Cucumis sativus). The sweetest cucumber we have tasted, this Japanese variety is a perfect snacking cucumber with no bitter flavor! Produces shorter, slightly thicker fruit than other Japanese varieties. Can be grown on the ground or on poles and is vigorous. Deep green fruit is about 7 to 8 inches long. Adapted to high temperature, humidity, and is disease and powdery mildew resistant.

Annual
Sprouts in 5–14 days
55–65 days to maturity
Full sun
Planting depth: 1/2 inch
Plant spacing: 12 to 18 inches
Ideal temperature: 70°F to 90°F
Frost hardy? No

Growing Tips, Tricks and FAQs
Growing Tips
Jibai Shimoshirazu cucumbers are compact, early producers that offer crisp, thin-skinned fruits ideal for fresh eating. Their name translates to “no cold-end defect,” referencing their consistent quality even in cooler conditions. The plants benefit from trellising and thrive in sunny, well-drained soil. Regular watering and prompt harvesting ensure peak performance and steady production. Some afternoon shade is beneficial in the hottest summer weather.

When to Grow
Direct sow Jibai Shimoshirazu cucumber seeds after the danger of frost has passed and soil temperatures reach at least 70°F. For cooler climates, start seeds indoors 3–4 weeks before your last frost date. This variety thrives in summer warmth and produces reliably in raised beds, containers, or traditional garden rows. If you’re not sure how to find your first and last frost dates, consult our blog post 'Our Experts Answer Questions, Share Resources.'

How to Sow and Plant
Choose a sunny site with rich, loose soil amended with compost. Sow seeds 1/2 inch deep, spacing plants 12 to 18 inches apart in rows or mounds. Install a trellis early to support the vines and promote straight fruit development. Water gently after sowing and maintain steady soil moisture during germination and early growth.

How to Grow
Keep soil consistently moist but not waterlogged. Apply mulch to retain moisture and suppress weeds. Feed with a balanced organic fertilizer every few weeks. Support vines with a trellis to improve air circulation and ease of harvest. Pick fruits at 5–7 inches for best flavor, and harvest regularly to encourage ongoing yield.

How to Save
Select disease-free plants for seed saving.
Allow fruits to fully ripen on the vine (they will turn yellow or orange).
Scoop out seeds and pulp into a jar or bowl with water.
Ferment at room temperature for 2–3 days, stirring daily.
Rinse seeds thoroughly and dry on a screen or paper towel for 1–2 weeks.
Store in a cool, dry place in a labeled and dated airtight container.
FAQ
What makes Jibai Shimoshirazu cucumbers special?
This Japanese heirloom is named for its resistance to the “cold end” defect, producing smooth, flavorful cucumbers consistently. Its compact vines are great for smaller gardens or container growing.

Can Jibai Shimoshirazu cucumbers be grown vertically?
Yes, trellising is beneficial and recommended. It keeps the fruits clean and straight, saves space, and allows for better airflow around the plant to reduce the risk of fungal disease.

Are these cucumbers good for pickling?
While they shine fresh due to their delicate skin and crisp bite, Jibai Shimoshirazu cucumbers can be used for light pickling when harvested small and firm for the best texture.