How to grow sweetcorn
Sweetcorn from the shops is unrecognisable from cobs harvested from your own garden - its sugars start to turn to starch as soon as it is picked, so the only way to truly appreciate sweetcorn at its very best is to grow your own.
It is often believed that a crop of sweetcorn takes up a lot of room, mainly because it needs to be grown in blocks rather than rows to ensure pollination. However, it is possible to grow sweetcorn in large pots and there are also varieties of mini sweetcorn available that are perfect for container growing. Wherever you grow it, sweetcorn needs a bright, warm, sheltered spot and well-draining, fertile soil.
How to grow sweetcorn
If you're wondering when to sow sweetcorn, it depends if you are sowing indoors or out. A good tip on how to grow sweetcorn is that it needs warmth to germinate and ideally should be sown indoors or under glass in April or May. Sow two or three to a pot or modular tray, thinning to leave the strongest seedling after germination. Sweetcorn is quite slow to germinate, so be patient! If you prefer to sow directly in the ground and want to know when to sow sweetcorn, wait until frosts have definitely passed, or grow from young plants from the garden centre in June. Plant out indoor raised plants after frosts have passed in late May or early June, hardening them off over a couple of weeks first.
Another good tip on how to grow sweetcorn is that traditional sweetcorn plants are always planted in blocks and not rows. Sweetcorn is wind pollinated and planting in blocks helps to maximise pollination, although this is not so crucial with the mini varieties of sweetcorn, as these are harvested before pollination even occurs. If you are growing sweetcorn in a small space, only grow one type. Different varieties planted too close together may cross-pollinate in the wind and the flavour of both will be poor.
A good guide on how to grow sweetcorn is to stake plants grown in an exposed position, or if they are particularly tall to mulch around their base with garden compost. This will help to keep in moisture, keep plants stable and protect any roots that appear at the soil surface from drying out.
Keep plants well watered, particularly when in flower. Tap the flowers, which are male, to help the pollen shed on to the female tassels below.
When to harvest sweetcorn
You can tell when to harvest sweetcorn when the tassels turn rusty brown. Another tip to knowing when to harvest sweetcorn is to pierce a kernel with your thumbnail - if the sap that is released is creamy, the cob is ripe; if it is clear, leave it a little longer. Twist the cobs off the stem just before you eat them, otherwise keep the leaves on the cobs and put them in the fridge as quickly as you can. Sweetcorn is always best eaten straight after picking.