Sweetest Sweetcorn

It’s at its sweetest fresh off the cob before the sugars start converting, so it’s always best to grow your own!

The idea of corn on the cob smothered in melting butter is a mouth-watering prospect. For home gardeners, sweetcorn is the domestic counterpart of field maize, and it’s an easy, undemanding crop to grow. It may be a South African staple, but like chillies, tomatoes and potatoes maize is a precious gift to us from the Americas, cultivated by the Aztecs of Mexico long, long ago.

Avoid this common mistake

Because this tall-growing plant is wind pollinated, never plant it in a single row where wind blowing from one side or another could blow the pollen away without it ever making contact with the tassels. Cobs that weren’t pollinated will be missing half their kernels. Always plant corn in blocks of 2-3 rows, running north to south. Ideal spacing is 35-45cm between plants and 60-75cm between rows.


Sow in situ, and plant two seeds together in each hole. Thin out the weaker plant later. Soil should be enriched with compost and raked level, and sticks and stones should be removed. Watch out for cutworm – put down bait or surround newly germinated plants with a cardboard collar (toilet roll) pushed a few centimetres into the soil.

General care

  • Sweetcorn requires plenty of water.
  • Remove weeds by hand, because digging could damage the shallow root system.
  • Keep soil moist with a layer of mulch.
  • Apply a nitrogen-rich fertiliser when plants are knee high, and repeat two weeks later.
  • Prevent bird damage by tying the end of the cobs closed with twine, raffia or a leaf closest to the end of the cob.


Each plant produces 1-2 cobs and these are ready for picking 10-12 weeks after sowing. Harvest when the cobs are plump and well-filled. Test for readiness by piercing a kernel – if it is still milky it is ready for eating. The tassels should also be dry and withered. Try to cook it within 30 minutes of harvesting, before the sugars start converting to starch.

Tips for Success

  • Grow sweetcorn in blocks, not rows. For cobs to form, the female flowers need to be pollinated by the male flowers. Growing them in blocks allows the wind to more effectively pollinate the plants. That won’t happen if they are planted in a row.
  • Make sure plants grow in full sun and in deeply prepared, fertile soil, with a layer of compost as mulch.
  • Sow where the plants are to grow – if roots are disturbed by transplanting it delays the growth.
  • Space plants 30-35cm apart and with a space of 50-60cm between rows. Spacing too close can also result in poor pollination.
  • Cobs must be harvested within 2-3 days of being harvest-ready, when the tassels/silks of the female flowers have completely withered and turned brown. Leaving cobs on for too long results in chewy, inedible cobs.
The Gardener