Examine the silk on the ears of corn. Silk on mature ears appears brown and dry close to the tip.
Peel back the husks carefully to expose the top kernels. Ensure that the kernels have filled out at the tip of the ear; immature corn ears do not have full, juicy kernels that reach to the tip.
Puncture a large, plump kernel with the tip of your fingernail. Examine the juice that runs out of the kernel. The juice should appear milky white, not clear.
Grab the corn ear at the base when it is ripe. Twist the ear downward from the base to remove it from the stalk. Harvest sweet corn in the morning.
Store sweet corn in the refrigerator immediately after picking. The quality of the corn deteriorates rapidly once you harvest it. For best taste, store the corn at 32 degrees Fahrenheit for no longer than 4 to 8 days before consuming it.