Depends how quickly you want them to die. Never use salt. Sprite is a great floral food.
Salt does not spoil, does not require refrigeration.
Salt is used to absorb moisture from the flower, hence 'dried flower'. By absorbing the water, the rate of decomposition of the flower is significantly reduced allowing the dried flower to last longer.
Maybe because salt serves as a preservatives when added to water that is why flowers stays fresh longer. Same thing when preserving foods, salt plays an important factor.
only perineals
no
if you put Sprite in your water it will make the flowers last longer
Silk flowers or artificial flowers will be just fine. Not only can they be more expensive than fresh cut flowers or arrangements but will of course last longer.
Malians used salt to make there food last longer.
I can't find any evidence that this would make them last longer. In fact I can't find any evidence of anyone putting flowers in a water & batteries mix.
soapy water
Salt, sugar, vinegar, drying or freezing