How to grow sweetcorn

How to grow sweetcorn

Learn how to grow delicious sweetcorn, in this detailed, practical Grow Guide.

A table displaying which months are best to sow, plant and harvest.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Sow
Sow

Do not Sow in January

Do not Sow in February

Do not Sow in March

Do Sow in April

Do Sow in May

Do Sow in June

Do not Sow in July

Do not Sow in August

Do not Sow in September

Do not Sow in October

Do not Sow in November

Do not Sow in December

Plant
Plant

Do not Plant in January

Do not Plant in February

Do not Plant in March

Do not Plant in April

Do Plant in May

Do Plant in June

Do not Plant in July

Do not Plant in August

Do not Plant in September

Do not Plant in October

Do not Plant in November

Do not Plant in December

Harvest
Harvest

Do not Harvest in January

Do not Harvest in February

Do not Harvest in March

Do not Harvest in April

Do not Harvest in May

Do not Harvest in June

Do not Harvest in July

Do Harvest in August

Do Harvest in September

Do Harvest in October

Do not Harvest in November

Do not Harvest in December

  • Average Yield

    6-9 cobs per sq m

  • Spacing

    45cm apart

    45cm between rows

  • Depth

    1cm

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.

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How to grow sweetcorn

Sow sweetcorn seed in small pots or modules in late spring and plant out into rich, moist soil in a sunny spot, when all risk of frost is passed. Sweetcorn is wind pollinated so plant in blocks, rather than rows. Water plants regularly, and consider mulching around the base of each plant to lock moisture into the soil. Harvest the sweetcorn cobs when the silky tassels turn brown and the kernels, when pressed with a thumbnail, exude a milky liquid. Twist the cobs to remove them from the main stem. Eat as soon after harvesting as possible, for the sweetest taste.


How to sow and plant out sweetcorn

Planting sweetcorn seeds in pots
Planting sweetcorn seeds in pots

Sweetcorn is a tender plant, so choose a sunny, sheltered spot for it. Ideally, you should have dug in lots of well-rotted garden compost the previous autumn to feed the soil.

In April or May, sow seeds in pots filled with good quality compost. Sweetcorn seedlings hate root disturbance so it’s best to give each seed it’s own pot. Water well, then place on a warm, sunny windowsill or in a greenhouse to germinate.

Once all danger of frost is over, harden off the young plants by putting them outdoors during the day for a week or so to acclimatise them to cooler outdoor conditions. Plant sweetcorn outside in a warm, sunny, sheltered spot, spacing plants in a grid at least 45cm apart. As sweetcorn is wind pollinated, plants must be grown in a large block (perhaps 4×4 or 5×5) rather than a single row. Try planting sweetcorn with courgettes, which thrive in the same conditions.

In this video guide, Monty Don pots up sweetcorn seedlings sown earlier in the year, explaining the right compost mix to use and where to grow them:

Watch Monty plant out his sweetcorn in blocks, in this short gardeners’ World clip:


How to care for sweetcorn

Watering a sweetcorn crop

Water plants regularly, especially during dry spells, as sweetcorn uses a lot of water due to the large leaf area of each plant. Spread mulch around the base of the plants to keep the roots cool and moist. In windy weather, plants may loosen in the ground, so build soil up around the stem bases to stabilise them.


Growing sweetcorn: problem solving

Protect sweetcorn plants from mice, birds and slugs. Sweetcorn has shallow roots that are easily damaged by hoeing.


Harvesting sweetcorn

Harvesting sweetcorn

Each sweetcorn plant should produce one or two cobs. Sweetcorn cobs are ready to harvest when the silky tassels turn brown and the kernels, when pressed with a thumbnail, exude a milky liquid. Give cobs a sharp twist to remove. Pick moments before using, because the sugars start converting to starch the minute you harvest them. Supersweet varieties, however, will stay sweeter for a couple of days.

In this short video clip from Gardeners’ World, Monty Don explains how to tell when sweetcorn is ripe and ready to harvest:


How to prepare and use sweetcorn

Strip away the husks and silky tassels and snap off the stalk. Steam, microwave or barbecue the cobs until al- dente and dot with butter.


How to store sweetcorn

It seems a shame to strip the kernels from the cobs so, instead, blanch them whole in boiling water for four minutes, drain them and then wrap in plastic bags and freeze.

Keep sweetcorn sweet

If you’re growing a Supersweet variety, position the plants as far from other sweetcorn varieties as possible, otherwise they may cross-pollinate and the sweetness of the crop will reduce. Ideally, just grow one variety at a time on your veg plot or allotment.

Gardening gloves. Photo: Getty Images.

Great sweetcorn varieties to grow

Golden-yellow kernels of fresh sweetcorn
Golden-yellow kernels of fresh sweetcorn
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  • ‘Earlybird’ – earliest maturing Supersweet variety, it has good tolerance of cold soil
  • ‘Lark’ – a Tendersweet variety for superior sweetness, with softer, less chewy kernels
  • ‘Mirai Bicolour’ – the cobs have white and yellow kernels
  • ‘Rising Sun’ – delicious Supersweet cobs on very vigorous plants, it’s reliable even in poor summers
  • ‘Swift’ – early-maturing, extra tender Supersweet variety, dwarf habit. It will cope with cold soil