"It is very important to harvest sweet corn at the proper stage of maturity," according to the extension folks at Purdue. "The critical time is the milk stage, a stage when the juice in the kernel appears milky when you puncture the kernel with your thumbnail. Sweet corn remains in the milk stage for a relatively short period, so check the ears frequently. Corn that is too young will ooze a watery material, while ears that are too old will have a tough, doughy kernel. During the milk stage, the unhusked ear should feel firm, have full kernels at the tip of the ear, and have brown, dry silks. Generally, ears should be ready about three weeks from silking time."
Some tips from www.ehow.com:
Corn is a big-time consumer of phosphorus and nitrogen. If the leaves start to yellow, it's a sign of nitrogen deficiency; correct the problem by spraying with manure tea or fish emulsion.
To keep fresh corn coming through the season, make successive plantings every two weeks. Crops planted later, when warm weather has settled in, will mature more quickly than earlier plantings.
Corn can take up to 90 toasty-warm days to mature. If your growing season isn't that long, look for faster-growing varieties such as 'Precocious' (70 days, with more cold tolerance than most), 'Seneca Brave' (72 days) or 'Breeder's Bicolor' (73 days).
Deer and raccoons love corn. The best way to deter these and other four-legged diners is to install an electric fence. Failing that, try adorning your corn patch with whirling metallic pinwheels, shiny windsocks or lights timed to go on and off through the night - assuming neighbors' windows don't overlook your garden.
Sara Busse is a Charleston resident and master gardener. She may be contacted at sjbu...@gmail.com.