May / Jun
Jul / Aug, Sep / Oct
Indoors | Outdoors

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.

  • Sweetcorn grows best in soil that has had compost and a general fertiliser added, so we suggest adding some fertiliser a week or two before sowing/transplanting.
  • Sow seeds in May indoors in pots for later transplanting.
  • Sow small pots about 2-3cm deep – one seed per pot.
  • Sweetcorn will need temperatures of 20°C so a warm sunny windowsill or a heating mat is required.
  • Plant out the seedlings when they are around 8cm tall (in June), after the danger of frost has passed. They need warmth, shelter and sunshine to thrive.
  • Sweetcorn plants are wind-pollinated. To facilitate this they are sown in “blocks” not in long rows (e.g. nine plants put in three rows of three, instead of a row of nine), or double rows rather than a single long row.
  • Plant them 40cm apart.
  • Weed carefully around plants to avoid damaging the plants’ shallow roots.
  • Sweetcorn plants don’t need a lot of watering except when the cobs are starting to fatten up.
  • Timing is crucial – sweetcorn is generally ready when the tassels 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 are ready. 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. Cook quickly before the sugar turns to starch.
  • Sweet Nugget F1

Generally trouble free, though yields are very poor if grown outside in a cool summer.

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