Each sweetcorn plant should produce one or two cobs. Sweetcorn cobs are ready to harvest when the silky tassels turn brown and the kernels, when pressed with a thumbnail, exude a milky liquid. Give cobs a sharp twist to remove. Pick moments before using, because the sugars start converting to starch the minute you harvest them. Supersweet varieties, however, will stay sweeter for a couple of days.

Advice from Gardener’s World

In a short clip from Gardener’s World, Monty shows how it’s done here