Cut flowers are a beautiful addition to every home and you can buy them in all shapes and sizes. Preservatives are an effective way to make the flowers last so you can enjoy them longer. Although you can buy commercial brands of flower preservatives, it is also possible to make your own mixtures at home provided you include the key ingredients the flowers need.
Flowers need carbohydrates to give them energy for activities like respiration and growth. Most cut flowers are harvested before they are fully mature so adding sugar to the water they are displayed in will help keep their energy levels high. According to the University of Massachusetts extension service, the amount of sugar each variety of flower needs varies, but most flowers benefit from a 2 percent sugar solution, which is the equivalent of 4 level teaspoons dissolved in a liter of water.
Household bleach or a brand called Physan, which is used in restaurants, acts as a biocide and can help plants last longer. Before plants start showing signs of decay, bacteria and fungi can make their way up the plant's stem, inhibiting its water intake and causing the plant to wilt prematurely. You can mix a suitable concentration by adding 1 ml of bleach to a liter of water or 0.5 ml of Physan to a liter of water.
Lemon juice can be used to acidify the water. The flowers' own cells have an acidic pH so this addition helps raise the acidity of the water to a level that is more equal to the cells. It also helps maintain the color of petals. The University of Purdue Horticulture Department suggests combining 2 tablespoons of fresh lemon juice with 1 tablespoon of sugar and a solution of 1/2 teaspoon of house chlorine in a liter of water.
White vinegar can be used in place of the lemon juice. It serves the same function as its citrus counterpart-- to make the water less alkaline and help maintain the flowers' pigment. If you choose to use white vinegar in your flower preservatives, the University of Purdue Horticulture Department advises a combination of 2 tablespoons of vinegar, 2 tablespoons of sugar and 1/2 teaspoon of household bleach in a liter of water.