Onion Senshyu

What Onion Senshyu is

Onion Senshyu (Allium cepa L.) is a biennial crop grown for harvest as early as the first year, from the onion family (Amaryllidaceae). Onion Senshyu is one of the original Japanese overwintering varieties, which has proved itself successfully for many years.

This reliable crop gives good yields of semi-flat onions with a yellow skin.

This variety is grown specifically for autumn sowing, to mature the following July, and is not suitable for sowing in mid-spring.

It is eaten green and as bulbs. It is added to salads and various dishes.

Onions contain large amounts of provitamin A, vitamins C, E, K and above all B vitamins, as well as calcium and potassium salts, which de-acidify the body.

The essential oils contained in onion juice have medicinal properties.

Onion from seed is the cheapest and surest way to a large harvest — for spring onions, onion sets or big bulbs for winter.

Key features

• Measured germination rate of the batch: 96%
• Pack size: 0.7 g
• Seed origin: Italy
• Sowing: March and April, and September and October; direct or as seedlings
• Harvest: June – October
• Position: sunny spot

When to sow Onion Senshyu

Onion Senshyu seeds are sown in March and April and September and October. Harvest in June – October. The months are a guide for a temperate climate — in warmer areas sow 1–2 weeks earlier, in cooler or upland areas, later.

How to sow and grow Onion Senshyu

• Sowing method: direct or seedlings
• Depth: 1–1.5 cm
• Spacing: 8–10 cm in the row, 25–30 cm between rows
• Germination: 10–14 days at 15–20 °C
• Position: sunny spot

A high-yielding, overwintering variety. Best planted between 15 September and 15 October. If the weather is mild, it is best to plant as late as mid-October. Sow the seeds 30-40 cm apart, at a depth of 1-2 cm. You can sow it in greenhouses or outdoors. This plant requires well-worked soils rich in nutrients to grow well and give abundant crops. After emergence the plants should not be too dense, so they are thinned to a distance of about 25 cm.

Sow in early spring in loose, weed-free soil. Weed regularly — onions do not tolerate competition. Stop watering 3–4 weeks before harvest.

Harvest and use

The bulbs are harvested when the neck softens and the leaves flop over; dry them in the shade for 2 weeks before storing.

Frequently asked questions

When should Onion Senshyu be sown?

The recommended months for sowing are March and April and September and October. Sowing method: direct or seedlings.

What is the germination rate of the seeds?

The measured germination rate of this batch is 96%. The test was carried out under controlled laboratory conditions; in the field, emergence depends on soil, temperature and moisture.

Can a large onion be grown from seed in one year?

Yes — with early sowing (February–March) for seedlings or direct, most varieties form bulbs in the very first year.