Usually vase life' of carnations is finished after approximately one week because of shrinking, caused by ethylene.
Silver is counteracting this effect of ethylene.
Silver, applicated as silverthiosulphate to the stem base, is transported quickly to the flower (Veen and Geijn, 1978) and as an effect, shrinking is inhibited of at least considerably delayed.
The silverthiosulphate complex (STS) can be composed by solving AgNO3 and Na2S2O3.5H2O in the molar ratio of 1/8. It must be applicated shortly after harvest, during at least two hours, in a concentration of 0.2mM AgNO3 and 1.6mM Na2S2O3.5H2O.
It has a very good effect on many cultivars, the effect being somewhat larger, generally, on standard carnations than on spray carnations.
The stems can stand in the silversolution up to 96 hours (in 9°C) without decrease of the effect or injury.