Wet fall weather conditions can lead to premature germination ("vivipary") of corn kernels on the ear in some fields. Hybrids affected have ears that are still in the upright position on stalks, which allows water to pool in the husks for extended periods. Corn germination is regulated by a hormone balance within the kernel. If this balance is tilted toward "germination" as opposed to "storage," and the environment is ideal for absorption of water by kernels, sprouting may occur. Premature germination of kernels on the ear is most likely to occur when kernels have dried down to 20% moisture or less and are then rewetted by fall rains.