All about growing Sweetcorn from seed

Growing Guide

Home-grown Sweetcorn cooked within minutes of picking – or even eaten raw – is simply the sweetest and juiciest sweetcorn you’ll ever taste. A favourite allotment crop, its statuesque, leafy structure and easy-to-grow nature make it great to plant in bold blocks in your borders, or as a productive screen to divide up areas of your vegetable plot.

I would urge gardeners not to rush to sow their seeds in the February-March peak seed sowing sessions; with early sowings you risk failure with low temperatures.

Sow sweetcorn seeds from April to May in 9cm pots of free draining seed compost at a depth of 2cm. Place in a propagator or seal inside a polythene bag until after germination. After germination, grow sweetcorn plants on in cooler conditions for 10 - 14 days. For an extended harvest sow seeds three times, three weeks apart.

When all risk of frost is passed, transplant into fertile, well drained soil in full sun, with shelter from winds. The tassels at the top of the plant and laden with pollen and are wind pollinated and should therefore be planted in blocks rather than rows to ensure good pollination. Plant 40cm between each plant.

Direct sow sweetcorn seeds outdoors in blocks, not rows in May once the soil has warmed, 2cm deep and a distance of 40cm apart. Sow 2 seeds per station and thin out the weakest seedling after germination.

  • Key Information

    Height: 180cm+

    Spread: to 45cm

    Half hardy annual

    Full sun

    Germination: 10 - 14 days

    Harvest: From 10-12 weeks

  • Sowing & Growing Schedule

    Sow Indoors: April to May

    Sow Outdoors: May

    Plant Out: June

    Harvest: August to October

  • Varieties we recommend

    Swift F1

    Minipop

Top Tip

Pollination can be helped by giving the plants a gentle shake once the tassels appear on the cobs.

'Supersweet' cultivars, such as those available from Collie Flowers, are much sweeter than the older varieties and retain their sweetness for longer, but are less vigorous. Take care not to grow Supersweet plants next to other cultivars, as cross-pollination will result in poor flavour.

With mini-corn / baby sweetcorn varieties the cobs are ready to harvest when they are approx. 10cm long, unlike standard sweetcorn when you wait for the end tassels turn brown.