How to Grow Sweetcorn

Freshly picked sweet corn straight from the garden bursts with flavour – sugar in the sweet corn doesn’t have time to turn to starch when you eat it so soon after picking.

Plant it out in the spring and you’ll have a late summer of cobs – just follow our step by step growing guide.

When to plant Sweetcorn

Plant seeds in April, and put out plug plants in late May or June. A location with full sun and shelter from any strong winds is required. Planting out in a large block is best, as wind pollination is needed – pollen from the male flowers falling down to the female tassels, where the cobs will grow.

If you do have the space to grow in a block, reckon on a minimum of 1.2 metres squared. Sweet corn is deep-rooted, so it doesn’t grow well in clay-based soils.

How to plant Sweetcorn

To sow seeds into pots, fill a 7.5 cm pot with compost, and make a 2 to 3 cm hole with a dibber or the end of a pencil. Put two seeds in, cover and water. Leave the pots on a windowsill to germinate. Remove the weaker seedling when the growth of 2 cm has been achieved, and toughen your plants up in a shady location outside for a week before planting out.

To plant outdoors, dig out the intended bed deeply, mixing in well-rotted manure. Do this as early as possible – ideally the previous autumn. Closer to the time of planting, remove weeds and large stones, digging over the ground. Level the ground and rake over. Make individual holes for each plant and gently firm into the ground. Plant in blocks instead of rows, with 30 to 35 cm gaps between plants and roughly 60 cm between rows. Make the block as large or as small as you need. Use protective fleece in cooler spells when the plants are still vulnerable. Water regularly, especially once cobs begin to form. Sweet corn plug plants work well, transplanting easily and establishing quickly.

Harvesting Sweetcorn

Watch the tassels at the end of the cob – when these turn brown, harvest time has arrived. You can double test by removing a section of husk and squeezing a kernel. When the juice is milky the cob is ready. To harvest a cob, twist it away from the plant. You can freeze cobs for longer-term storage.

Through the year

Take care that you do not damage the sweet corn’s surface growing roots – weed by using a Dutch hoe to slice off weeds.

The surface roots can be protected by building up soil around the stems in mounds, which will also encourage further stabilising roots to grow – good protection against any windy spells or if your plants are wavering.

Handy tips

If space is limited you can under crop between the sweet corn plants – their relatively compact foliage allows through plenty of light and won’t crowd out smaller vegetables grown between.

For example, you could try dwarf beans, radish or lettuce.

Ready to plant your own vegetables now you know how to grow Sweetcorn? Take a look at our vegetable seed collection.