Dahlias don’t unfurl much once they’ve been harvested so it’s important to not pick them too early. Harvest when blooms are three-quarters of the way open, but not overly ripe. Check the back of each flower head, looking for firm and lush petals versus papery or slightly dehydrated ones. Place into water with hydrator, or sear stem ends by placing into 160°F to 180°F (just off boiling) water and allow to cool for one hour. Expect a vase life of 5 days.