Sweet Corn Northern Extra Sweet Seeds

Sweet Corn Northern Extra Sweet Seeds

Sweet Corn Northern Extra Sweet Seeds produce golden-yellow cobs filled with tender, sweet kernels. This extra-sweet sweetcorn variety is suited to growing in the UK's shorter summer season, making it a useful choice for gardeners in cooler regions.

Northern Extra Sweet Sweetcorn produces upright plants with well-filled cobs that are best harvested fresh, when the kernels are juicy and at their sweetest. The cobs can be boiled, steamed, grilled or roasted and are particularly enjoyable when cooked shortly after picking.

Sweetcorn grows best in a warm, sunny and sheltered position with fertile soil. Plants should be grown in blocks rather than single rows to encourage good wind pollination and well-developed cobs. Northern Extra Sweet is suitable for kitchen gardens, allotments and vegetable plots where there is room to grow several plants together.

Key Features

Produces golden-yellow cobs with tender, sweet kernels.

Extra-sweet sweetcorn variety suited to shorter growing seasons.

Suitable for growing in cooler UK regions.

Upright plants producing well-filled cobs.

Useful for boiling, steaming, grilling and roasting.

Best harvested fresh for sweetness and flavour.

Suitable for kitchen gardens and allotments.

Grow in blocks to encourage good pollination.

How to Grow Sweet Corn Northern Extra Sweet Seeds

Sow Sweet Corn Northern Extra Sweet Seeds indoors from April to May in deep pots or modules filled with good-quality seed compost.

Sow seeds approximately 2–3cm deep, placing one seed in each module, and maintain a temperature of around 18–21°C during germination.

Keep the compost lightly moist but not waterlogged. Seedlings generally appear within 7–14 days, depending on temperature and growing conditions.

Grow young plants on in bright, frost-free conditions. Sweetcorn dislikes root disturbance, so take care when transplanting.

Gradually harden plants off before planting outdoors after all risk of frost has passed, usually from late May or early June.

Alternatively, sow seeds directly outdoors from late May to early June once the soil has warmed sufficiently.

Choose a sunny, sheltered position with fertile, well-drained soil. Incorporate well-rotted compost or organic matter before planting.

Plant sweetcorn in blocks rather than single rows, allowing approximately 40–45cm between plants. Growing in blocks helps the wind carry pollen between plants, encouraging better cob development.

Water regularly during dry periods, particularly when the tassels and silks are developing.

Harvest cobs when the silks have turned brown and the kernels release a milky liquid when pressed. This indicates that the sweetcorn is ready for picking.

Sweet Corn Growing Tips

Choose a warm, sunny position sheltered from strong winds.

Grow plants in blocks to improve wind pollination.

Avoid disturbing the roots when transplanting seedlings.

Keep plants well watered during flowering and cob development.

Mulch around plants to help retain soil moisture.

Check cobs regularly as they approach maturity.

Harvest when kernels are full and release a milky liquid when pressed.

Cook or refrigerate cobs soon after harvesting to maintain their sweetness.

Keep extra-sweet varieties isolated from other sweetcorn types with incompatible genetics to help maintain eating quality.

Frequently Asked Questions

Is Northern Extra Sweet suitable for growing in the UK?

Yes, Northern Extra Sweet is suited to the UK's growing conditions, including areas with relatively short summer seasons.

When should Northern Extra Sweet Seeds be sown?

Sow indoors from April to May or directly outdoors from late May to early June once the soil has warmed.

Why should sweetcorn be planted in blocks?

Sweetcorn is wind-pollinated. Growing plants in blocks rather than single rows helps improve pollination and encourages well-filled cobs.

How do I know when sweetcorn is ready to harvest?

The silks usually turn brown, and a kernel releases a milky liquid when pressed. Clear liquid suggests the cob is immature.

Can Northern Extra Sweet be grown in containers?

Sweetcorn is generally better suited to open ground or large raised beds because several plants are needed for reliable pollination.

Does sweetcorn need plenty of water?

Yes, regular watering is particularly important during flowering, pollination and cob development.

Can Northern Extra Sweet be grown alongside other sweetcorn varieties?

Extra-sweet sweetcorn varieties can lose eating quality if cross-pollinated by incompatible sweetcorn types. Grow them separately or choose varieties that flower at different times.

Perfect For

Kitchen gardens

Allotments

Vegetable plots

Raised beds

Cooler UK growing regions

Fresh summer harvesting

Grilling and roasting

Home cooking