Posted: 13/05/2016 at 17:41
No is the short answer.
Marketmore is an old cucumber that is usually grown outside.
Canteloupe Hales best jumbo dates back to 1924, and is a heritage variety, seed guardians grow it on and distribute seed.
old varieties of tomato, especially heritage types are not usually hybrids.
F1 hybrid seeds are usually expensive because the cross between two specific parents has to be made each time, to give hybrid vigour.
Tomatoes such as Sungold are F1 hybrids. 10 seeds to a packet.