Seeds: Species, F1, F2, F3

P1 Species seeds are from two parents of the same species or self pollination
— breed true

F1 seeds are hybrids created from two unrelated parents ( children )
— hardy crosses, usually vigorous, healthy plants, children usually look like the children

F2 are self pollinated F1s or pollinated by other F1s ( grandchildren )
— might look like parent, might look like mailman, most diverse, greatest diversity in this cross

F3 are self pollinated F2s or by other F2s ( great grandchildren )
— who knows? usually selected to strengthen an F1 trait

F4, F5, F6 can also be found

The ‘F’ is short for filia

Species seeds are the most expensive, each F? gets cheaper the farther you travel down the family tree

S seeds are self fertilized seeds that have been treated chemically, or otherwise, to create a mutation. It’s not an accepted botanical grading, but often used by hobbyists