A popcorn plant is a type of maize that is harvested and dried to create popcorn kernels, according to the Popcorn Board. Popcorn plants grow about 8 feet tall, and they need up to 2 feet of water to mature.
Much of the moisture the popcorn plant takes in is stored in the kernels, which allows them to pop when they are heated. The plant is ready to harvest when the leaves and stalk are brown and the kernels are hard. Once the popcorn cobs are cut, the kernels take up to a year to dry while the cobs are in storage. Commercial popcorn growers use an air dryer to speed the drying process.