I copied this from the website (url at the bottom). More info there if you want it.
"Harvesting and Handling
Ornamental corn must be harvested by hand when the husk is dry. When ears of ornamental corn have lost their green color and begin to dry down, they have reached full maturity. If warm, dry weather is expected, the ears may be left on the plants until sales are expected.
To harvest, break off ears with a quick downward motion. Be careful not to damage the ear or husk attached to it. Pick ears carefully so that the kernels are not damaged. Spread the ears out to dry in a shallow pile where there is good air circulation and under cover if the weather has been damp. Pull the" husk back if it is not completely dry at harvest. Be careful not to tear the husks because they contribute to the value of the ears. The husk and ear may become moldy if they are not handled properly. Pulling the husk back allows slightly damp husks and ears to dry quickly. When husks and ears are dry, tie the ears together with twine or rubber bands in bunches of two or three around the base of the ears and allow them to dry in a warm, dark, airy place. If husks are too dry, they tend to pull off or break easily from the ears, decreasing their value. Should this occur, wait for a humid or rainy day to prepare the ears for sale.
Do not box or bag ears when they are first harvested or they may mold. Mold may occur on both the husk and ear if proper handling and storage techniques are not used.
Ears can be used for ornamental purposes after a week of drying. During and after drying, ornamental corn may be stored in open wooden apple or cabbage bins. Growers with small quantities often suspend the ears in cabbage or onion sacks in a dry location until time for marketing. The ears are usually sold in groups of three. The three ears are held together with rubber bands or with a plastic sleeve similar to that used for dried flower arrangements. "
http://www.ca.uky.edu/agc/pubs/ho/ho81/ho81.htm