Don't throw away those last drops of soda! Pour about 1/4 cup into the water in a vase full of cut flowers. The sugar in the soda will make the blossoms last longer. Note: If you have a clear vase and want the water to remain clear, use a clear soda, like Sprite or 7-Up.
Just as it preserves your hairstyle, a spritz of hair spray can help your cut flowers look fresh longer. Stand a foot away from the bouquet and give them a quick spray, just on the undersides of the leaves and petals.
Apple Cider Vinegar
Everyone likes to keep cut flowers around as long as possible, and there are several good methods. One way is to mix 2 tablespoons apple cider vinegar and 2 tablespoons sugar with the vase water before adding the flowers. Be sure to change the water (with more vinegar and sugar, of course) every few days to enhance your flowers' longevity.
The secret to keeping cut flowers looking good as long as possible is to minimize the growth of bacteria in the water and to provide nourishment to replace what the flower would have gotten had it not been cut. Add a few drops of vodka (or any clear spirit) to the vase water for antibacterial action along with 1 teaspoon sugar. Change the water every other day, refreshing the vodka and sugar each time.
It's a tried-and-true way to keep roses and other cut flowers fresh longer: Put a crushed aspirin in the water before adding your flowers. Also, don't forget to change the vase water every few days.
Freshly cut flowers will last longer if you add 1/4 teaspoon bleach per quart (1 liter) of vase water. Another popular recipe calls for 3 drops bleach and 1 teaspoon sugar in 1 quart (1 liter) water. This will also keep the water from getting cloudy and inhibit the growth of bacteria.
Your posies and other cut flowers will last longer if you add a copper penny and a cube of sugar to the vase water. The copper in pennies is thought to act like an acidifier, which prevents the growth of bacteria.
Make your own preservative to keep cut flowers fresh longer. Dissolve 3 tablespoons sugar and 2 tablespoons white vinegar per quart (liter) of warm water. When you fill the vase, make sure the cut stems are covered by 3-4 inches (7-10 centimeters) of the prepared water. The sugar nourishes the plants, while the vinegar inhibits bacterial growth. You'll be surprised how long the arrangement stays fresh.