Adjustable seed meters having a first seed disk having first openings defined therein and a second seed disk having second openings defined therein adjacent to the first openings such that the first and second openings are alignable to form adjustable seed cells. Various embodiments have a plate adjustment drive system to rotate the first and second seed disks in relation to each other. Other embodiments relate to methods of automatically adjusting a seed meter during operation of the overall planting system.