Sweetcorn Growing Guide

There’s something pretty special about a handsome stand of homegrown sweetcorn. But the real prize lies in harvesting it. Picking the cobs, then excitedly peeling back the sheath to reveal those full, creamy kernels is just magical!




Why Grow It?

Sweetcorn takes up a good deal of space and gives a relatively low return – just two cobs per plant – it can also be difficult to grow well in Ireland given our relative lack of sun.  But the sheer pleasure of harvesting a fresh cob of corn and the incredible sweet taste make it worth a try.  They say you should run from the veggie patch to the kitchen when you harvest sweetcorn to cook it immediately – this is because as soon as you pick it the sugars in the corn immediately start to turn to starch and so the flavour is degrading literally by the hour.  So in other words – you will never taste anything like homegrown sweetcorn


Sow indoors in small pots about 2-3cm deep – one seed per pot.  Delay sowing until May.  They will need temperatures of 20 degrees celsius so a warm sunny windowsill or a heating mat is required.  Harden off well before planting out.


Plant out the seedlings when they are 8cm tall (in June).  They need warmth, shelter and sunshine to thrive.  Sweetcorn plants are wind-pollinated so to facilitate this they are sown in “blocks” or double rows rather than a single long row. Plant them 40cm apart.  Weed carefully around plants to avoid damaging the plant’s shallow roots.  Sweetcorn plants don’t need a lot of watering except when the cobs are starting to fatten up. Earth up around the stems to give plants support.  A top dressing of good compost around plants will help.  Sweetcorn can be grown wherever suits in your patch – they don’t need to be included in your rotation plan.


Timing is crucial – sweetcorn is generally ready when the tassles at the end of the cobs turn brown.  To test whether a cob is ready, peel back a few leaves and prick one of the kernels with your nail.  If the juice that comes out is milky, then you’re ready to rock.  If it’s watery, leave it another while.  If it’s starchy, you’ve left it too long!  To harvest cobs, hold the stem steady and then pull the cob downwards.

Recommended Varieties

  • Sweet Nugget F1


Mice, birds, squirrels and badgers love sweetcorn so you may have to net the whole crop if that’s a problem.

GIY Tips

  1. You can grow lettuce and other quick growing, ground-hugging plants underneath sweetcorn.  This is called undercropping. 
  2. When you plant the seedlings out first, cover with a bionet cloche, this will give them protection from wildlife, wind and cold nights.