Freeze drying is one of the most reliable ways to preserve the color and shape of a dried flower. Because it preserves the shape of the flower by freezing it before quickly drying it out, freeze drying can preserve flowers without significantly changing their appearance. And once freeze dried, if stored properly, these flowers will last for years. But the equipment requires a considerable investment. If you do not plan on making freeze drying a hobby or small business, consider having your flowers professionally freeze dried.
Cut the stems of your flowers on a diagonal.
Place the flowers in a vase and allow them to absorb water for 24 hours.
Strip the leaves off the stem. Also consider cutting the stem down as far as possible. Flower stems dry more slowly than petals and they will increase the freeze drying time of your flowers.
Set the freeze dryer's chamber to -5 degrees F. Turn the vacuum pump on for a few seconds to seal the door and hold the temperature.
Load the flowers into the chamber (according to the manufacturer's instructions) once its internal temperature has reached -5 degrees F. Turn off any interior lights, put the blackout cover in place (if present) and close the door. Then turn on the vacuum for a few more seconds to seal the chamber.
Allow the flowers to cool at -5 degrees F for 24 hours. Then turn the vacuum pump on.
Increase the internal temperature of the freeze dryer's chamber by 5 degrees F every 48 hours so that the internal temperature has reached 20 degrees F in 10 days.
Check on your flowers after 10 days. They are properly freeze dried when they are no longer cold to the touch. If your flowers are not fully dry, reinsert the flowers, close the door, turn the vacuum pump on and allow them to continue to dry at 20 degrees F. Check on your flowers once every 48 hours until they are dry.