Does a spoonful of sugar help flowers?

Cut flowers cannot photosynthesise once they are cut, so they rely on the sugars stored in their stems. Adding a small amount of sugar to the water gives them an energy boost, which can help them open fully and stay fresh longer. However, sugar also feeds bacteria, and bacteria clog the stems and make flowers wilt. To get the benefit without the downside, add a tiny amount of bleach, about a drop or two, or a splash of lemon juice, to keep the water clean. A common homemade flower food is one teaspoon of sugar, two teaspoons of lemon juice, and a quarter teaspoon of bleach per litre of warm water. Change the water every two to three days and re-cut the stems at an angle each time. This helps the flowers take up water more easily. Some flowers, like roses, benefit more from sugar than others. If you are using a shop-bought flower food sachet, follow the instructions on the packet, as it already contains the right balance of sugar, acid, and antibacterial agents. Remember that sugar alone will not save flowers that are already past their best. Start with fresh flowers, clean vases, and cool water for the best results.