What is the difference between F1 and heirloom seeds?
F1 hybrid seeds are the first-generation offspring of two deliberately selected, inbred parent lines. Heirloom (or open-pollinated) varieties breed true, producing offspring resembling the parent.
What F1 gives you. Crossing two distinct inbred lines produces hybrid vigour — offspring noticeably more vigorous, uniform and productive than either parent. F1 plants are typically higher-yielding, more disease-resistant, and strikingly consistent: they germinate together, grow at the same rate and crop at the same time. That uniformity is why commercial growers rely on them, since harvesting and supplying supermarkets requires predictability.
The catch is that F1 does not breed true. Save seed from an F1 plant and the second generation splits genetically, producing a variable mixture reverting toward the parent lines. Some will be poor. So F1 seed must be bought fresh each year, which is also commercially convenient for the companies producing it.
What heirlooms give you. Open-pollinated varieties produce offspring resembling the parent, so you can save seed year after year. Heirlooms are typically older varieties maintained by gardeners and seed libraries.
Their advantages: seed saving and self-sufficiency; far greater variety, including flavours and forms that never suited commercial production; adaptation to local conditions over generations if you save from your best plants; and preservation of genetic diversity, which matters given how narrow commercial crop genetics have become.
Their disadvantages: less uniform, often lower-yielding, frequently less disease-resistant, and cropping over a longer, less predictable window — which is actually an advantage for a home gardener who does not want forty tomatoes on one day.
Saving seed requires isolation for insect-pollinated crops, or the plants will cross with neighbours. Beans, peas, tomatoes and lettuce mostly self-pollinate and are the easiest to start with.
Neither is better. F1 for reliability and disease pressure; heirloom for flavour, diversity and seed saving.