To keep cut flowers fresh for longer, there are several things you can add to the water in the vase. Here are some tips from the search results:

• Clean water: Use clean, room temperature water to fill the vase.
• Flower food: Most fresh flower bouquets come with a packet of plant food. If yours didnt come with one, you can make your own by mixing 2 tablespoons of sugar with 2 tablespoons of white vinegar in the water. Alternatively, you can use a commercial cut-flower food that provides all the nutrition stems need.
• Acidic ingredients: Adding an acidic ingredient, such as lemon-lime soda, vinegar, or citric acid, to the water can help balance the pH level and inhibit the growth of bacteria.
• Bleach: Adding a few drops of bleach to the water can help kill bacteria and keep the water cleaner.
• Sugar: Dissolve sugar in warm water in the vase before adding the flowers. Sugar feeds the flowers and promotes opening of the blooms.
• Clean vase: Use a clean vase to prevent bacteria buildup.
• Trim stems: Trim all green and woody stems at a 45-degree angle to create a large surface area, ensuring maximum water absorption. Use clippers or shears for woody stems and sharp scissors or knives for other flowers. If possible, cut stems under water.
• Remove excess leaves: Removing excess foliage (and browning petals) is one of the first things you should do when you get your bouquet home. Remove the leaves below the water line, as the leaves will eventually rot and the bacteria in the water will hurt the longevity of the flowers.
• Change water: Change the water every two to three days and replace it every three to five, depending on cloudiness. Re-cut stems by an inch to let them drink more fully when replacing water. Keep flowers in a cool spot, away from direct sunlight.