When kernals are filled out well in the milk stage. There are only 72 hours from the beginning of prime eating quality until corn becomes over-mature. Avoid high temperatures when gathering. The cool of the morning is a desirable time. Older fruits will be dull in color, less crisp, may have objectionable seeds, and result in lower yields.
Older fruits become dull in color, soft, and seedy.
When foliage loses color and tops begin to fall over. As outer leaves become 8 to 10 inches long. New leaves will continue to grow from the center of each plant for a continuous harvest. Outer, older leaves may be taken from plants of either leaf or head lettuce as soon as the leaves are 4 to 6 inches long. New leaves will provide a continuous harvest of tender, tasty lettuce until hot weather brings on bitter flavor and seed stalks start.