Maturity dates listed on seed packets aren't always an accurate indicator of when to harvest; sweet corn can take a few days to a week longer to mature than expected. Check a few cobs: when they're ripe, all the others of the same variety likely will be too, if growing conditions are consistent.
Peeling back the husk to check for ripeness can dry out the upper kernels. When the silks turn brown, feel the tips of a few cobs. If the husk feels loose, wait a day or two. When the cob feels full to the tip, it's time to harvest.
Normal sugary corn should be canned or eaten within a few hours of harvest, but supersweets and sugar-enhanced corns retain their flavour for a day or two. For optimal sweetness, immediately plunge corn into icy water as you harvest, then refrigerate. Freeze any surplus, first boiling cobs for eight to 10 minutes, then chilling in cold water.
Gardens - Fruit & Vegetable Gardening
Summer stalk: Growing corn
Fresh-from-the-field, sweet corn brings the golden sunshine of late summer to the dinner table