F1 / Hybrid

Means it is a first generation hybrid seed/plant. The seeds have come about from cross pollinating plants. But fear not, cross pollinating is not a bad thing, and doesn’t mean GMO. GMO is a completely different process, and GMO seeds are not available to home gardeners, at the time of writing this, the rules are strict and for good reason. Back to F1/Hybrid, cross pollinating of plants happen all the time in nature. It’s a natural part of the pollination process, but in the case of F1 seeds/plants it’s been purposefully done to get a hybrid plant that is the best of two plants.

You can have Plant A, that is really big and bushy, and produces a lot of fruit, and Plant B that is smaller and doesn’t produce much fruit. But as a gardener I desire to have two of the best qualities from each. I desire a lot of fruit, and I want a small plant. Growers then produce a variety that is the best of both - Plant C. Or you may live in an area that is damp and rainy, and you may want to grow loads of courgettes. In an area that is damp and rainy, you’re more likely to get powdery mildew, in this instance you may want to find an F1 variety that has the very best chance of not succumbing to powdery mildew to increase your chances of getting a good crop.

Open Pollinated / Heirloom

Open pollinated plants happen all the time in nature. Insects, birds, wind, or other natural means does the job. It’s a natural part of the pollination process. You can expect this plant to only be pollinated by other identical plants. You can save the seeds from this plant, and you’ll be guaranteed that the parent plant will produce the same qualities in the child plant for another year. F1 plants aren’t guaranteed that same outcome, because with F1 varieties they’ve been cross pollinated with two varieties, so you may get some of the qualities of one and not the other, or more of one and less of the other.

Heirloom seeds / plants have some history to them - this history is defined differently depending on who you’re talking to, some describe this as pre WWII, some 50 years plus and other will regard heirloom as 100 years or older. The reason for it having to be pre WWII is because post 1945-1951 marks a new era of widespread hybrid varieties being used.

Contrary to popular belief, neither is better or worse it’s about gaining desired character traits in your crop.