Ways to keep flowers fresh include cutting stems at a slant, adding a preservative to the water, changing the water frequently, and removing flowers and leaves as they die. Moving the flowers to a smaller vase as the old stems are removed keeps the bouquet looking nice.
When cutting flowers directly from the garden, the ideal time is in the morning or early evening. Putting the flowers in lukewarm water immediately helps them start absorbing water. Once the flowers are inside, cutting the stems a second time under the water gets rid of air bubbles so the stems can easily absorb the water.
Flowers from a florist come with a packet of preservatives. An alternative is to make a preservative mixture at home, which can be done by mixing 1 cup of regular, clear soda with 1 cup of water and 1/2 teaspoon of bleach. The soda's sugar provides an energy source for the flowers, while the bleach keeps bacteria at bay.
Changing the water every few days gives the flowers a fresh drink. It also gets rid of the toxins that some flowers have in their sap. When the sap gets into the water, it can damage other types of flowers, making them die faster.