Certain flowers, like lilies, can be harvested before they open to extend their lives as cut flowers. Once in the water, the buds will open over the next week. But if you need the cut flowers for a special occasion, you can't always wait for Mother Nature to get around to it. As long as the first bud is cracking open on a lily stem, you can force the other buds to open, even if the stem is freshly cut. If the unopened blooms are already cracking open, you can force them open in as little as one or two days.
Fill the vase with 1 to 2 litres (1 to 2 qt) of warm -- not hot -- water so it is roughly half full.
Mix in 2 tbsp of sugar per litre (quart) of water in the vase until the granules dissolve.
Place the fresh-cut lilies into the vase.
Place a wooden dowel in the vase that is 2.5 to 5 cm (1 to 2 inches) higher than the tallest lily bud.
Place a roasting or clear plastic bag loosely over the top of the vase. Secure the bottom of the plastic bag around the top of the vase with a twist tie.
Move the vase to a warm, indoor spot where it will receive indirect sunlight.
Remove the bag, pull out the lilies and pour out the sugar water. If the lilies have opened, discard the dowel and the bag. Then fill the vase with cool water and replace the lilies. If they have not opened, move on to Step 8.
Fill the vase with warm water. Replace the flowers, dowel and plastic bag. Move the vase back to where it receives indirect sunlight. Change the water every three hours until the lilies open. Keep the bag on for three hours, then alternately off for three hours while you cycle the water. It may take as long as 72 hours to force closed buds open. Once the lilies open, follow the instructions in Step 7.
Do not cut lilies from the plant until at least one bud on the stalk is opening. Forcing fresh-cut lilies to open shortens their lifespan. You can force cracking buds open with your fingers, but you run the risk of tearing the petals. Prune the anthers from the flowers to keep them alive longer.