A planter comprising: a seed meter having a housing adapted to hold a pool of seed to be singulated and delivered sequentially; a seed sensor adapted to generate a signal for each seed delivered by the meter and passing the sensor, a seed delivery system to provide at least two different varieties of seed to the meter, the seed delivery system having a switching mechanism to change from a first variety of seed to a second variety of seed being delivered to the meter housing; a controller adapted to operate the switching mechanism to control which seed variety of the first and second seed varieties is delivered to the meter based on the location of the machine in a field wherein the controller is adapted to stop supplying a first seed variety to the meter before supplying a second variety to allow for substantial consumption of the first variety of seed in the seed pool prior to supplying the second variety of seed to the seed meter, the location of the machine in the field where supply of the first variety of seed to the meter is stopped is based on a programmed quantity of seed and the seeding rate wherein the controller is adapted to determine the programmed quantity of seed in the seed pool for each variety of seed during a meter calibration process, wherein the meter calibration process includes the steps of filling the meter housing with a first variety of seed, operating the seed meter, stopping the supply of the first variety of seed to the meter, continuing to operate the seed meter until a seed meter operational parameter indicates the seed meter performance has degraded indicating that the seed pool has been substantially depleted while counting the number of seeds delivered by the seed meter after stopping the supply of seed to the meter wherein the number of seeds delivered by the seed meter between stopping the supply of the first seed variety to the meter until meter performance is degraded is used as the programmed quantity of seed for the first variety of seed, characterized in that the seed meter is a pressure differential meter and the operational parameter is a change in the seed meter pressure differential. a seed meter having a housing adapted to hold a pool of seed to be singulated and delivered sequentially; a seed sensor adapted to generate a signal for each seed delivered by the meter and passing the sensor, a seed delivery system to provide at least two different varieties of seed to the meter, the seed delivery system having a switching mechanism to change from a first variety of seed to a second variety of seed being delivered to the meter housing; a controller adapted to operate the switching mechanism to control which seed variety of the first and second seed varieties is delivered to the meter based on the location of the machine in a field wherein the controller is adapted to stop supplying a first seed variety to the meter before supplying a second variety to allow for substantial consumption of the first variety of seed in the seed pool prior to supplying the second variety of seed to the seed meter, the location of the machine in the field where supply of the first variety of seed to the meter is stopped is based on a programmed quantity of seed and the seeding rate wherein the controller is adapted to determine the programmed quantity of seed in the seed pool for each variety of seed during a meter calibration process, wherein the meter calibration process includes the steps of filling the meter housing with a first variety of seed, operating the seed meter, stopping the supply of the first variety of seed to the meter, continuing to operate the seed meter until a seed meter operational parameter indicates the seed meter performance has degraded indicating that the seed pool has been substantially depleted while counting the number of seeds delivered by the seed meter after stopping the supply of seed to the meter wherein the number of seeds delivered by the seed meter between stopping the supply of the first seed variety to the meter until meter performance is degraded is used as the programmed quantity of seed for the first variety of seed, characterized in that the seed meter is a pressure differential meter and the operational parameter is a change in the seed meter pressure differential.