Miracle-Gro is the name of a line of fertilizer products manufactured by the Scotts Miracle-Gro company. The product line includes fertilizers for lawns, vegetable gardens and flowers. The products most commonly seen are consumer products for home gardens, patio plants and house plants. Because these products work so well on growing plants, people often want to know if they can use them on cut flowers as well. What it comes down to is whether or not a fertilizer designed for an actively growing plant has in it what a cut flower requires to last.
Most of the Miracle-Gro products, while they do not say they cannot be used on cut flowers, do specifically say they are to be used on outdoor plants, outdoor flowers and sometimes on container plants or flowers. Cut flowers are not listed as one of the uses for these products, since the requirements for cut flowers are different from those for growing plants. The exception to this is the Miracle-Gro Excel product, which has extra calcium and magnesium. Excel is recommended for cut flowers that require a boost of those specific minerals.
One alternative to commercial plant food is homemade food for cut flowers. Although many different recipes exist, one popular choice calls for the use of 1 cup of lemon-lime soda, not sugar free, 1 cup of water, and 1/2 tsp. of bleach. According to the National Gardening Association, this recipe has been found to be more effective for preserving cut flowers than commercial preservatives. The recipe can be doubled or tripled if needed.
The Brooklyn Botanical Garden (BBG) prefers another homemade preservative recipe for cut flowers. The recipe recommended by the BBG is to blend 1 tsp. of sugar, 2 tsp. of lime juice (lemon juice can be substituted) and 1 tsp. of household bleach in 1 quart of lukewarm water. Mix well and use to water the flowers. The sugar provides nutrition, the lime juice gives some acidity to the water and the bleach keeps the water free from bacteria.
To keep cut flowers fresh as long as possible, don't use a penny, aspirin or wine. According to the University of Minnesota, the best way to keep flowers fresh is to use a good commercial preservative and mix according to package directions. Never store flowers near fruit, because the gases given off will age the flowers prematurely. Put the flowers in the refrigerator when nobody is home, to slow respiration and water loss. Lastly, keep flowers away from hot or cold spots that may affect them adversely.