Good conditioning and harvest timing are the foundation. Here are additional steps to extend vase life once flowers are in an arrangement.
Bacteria is the enemy. Change water every 2–3 days. Re-cut stems at each water change. Add fresh floral preservative. Keep vases scrupulously clean between uses—wash with hot water and a drop of bleach.
Keep arrangements out of direct sun, away from heating vents, and away from fruit bowls. Ripening fruit releases ethylene gas, which accelerates flower aging. Cooler rooms extend vase life significantly. Some people place arrangements in a cool spot or even a garage overnight.
As individual stems fade, remove them. Decaying flowers release bacteria and ethylene that shorten the life of remaining blooms. Top up water daily—some flowers like ranunculus, anemones, and sunflowers are especially heavy drinkers.
If vase life is your priority, focus on growing lisianthus (10–14 days), zinnias (7–12 days), celosia (7–14 days), marigolds (7–10 days), and amaranth (10+ days).