Definition: Open pollinated or OP plants are varieties that grow true from seed This means they are capable of producing seeds from this seasons plants, which will produce seedlings that will be just like the parent plant.
However some plants will naturally be cross pollinated with other plants, so even if it is OP, the seeds resulting from a cross pollination could yield a different plant. Peppers will cross pollinate with other plants and if your sweet peppers are too close to your hot peppers, you will eventually wind up with a lot of hot peppers.
Examples: I like the old-fashioned open pollinated flowers because I can save their seeds and replant them next year.
