The "nutrients" are most likely an antibacterial that keeps the absorbed water fresh and clean, and there is probably some type of sugar based stuff to "feed" the plants or flowers, and something to keep the PH down, and maybe something to keep the flower stems from getting clogged.
Floralife is a floral additive product that is one example. It is non-toxic, but not recommended for human consumption...hmmm....
I dunno if it is harmful to cigars, but I'd go to a local florist shop and buy a brick or 2...