With good storage conditions (dry, at room temperature) our flower seed mixtures have no specific expiration date. However, the germination rate decreases over time.
You could still try sowing the flowers later than the two or four years we recommend, depending on the variety. Just keep in mind that it is just likely that fewer plants will sprout.
We only use seeds that are heirloom varieties. Other manufacturers often offer F1 hybrid varieties, which usually lose their germination capacity faster. All our seeds are free from pesticides and GMO-free.