Homemade Floral Preservatives Effects on Postharvest Performance of Selected Specialty Cut Species

Effects of homemade floral recipes applied as a 48 hours grower treatment or a continuous consumer (vase) application were studied on cut ‘ABC Blue’ lisianthus, ‘Double Eagle’ African marigold, ‘Red Bentley’ rose and ‘Deep Red’ zinnia. Cut stems were subjected to solutions containing 300 mg·L^-1 citric acid, 20 g·L^-1 sugar and either 200 mg·L^-1 Al₂SO₄ (citric-Al), 10 mL·L^-1 household bleach (citric-bleach), 0.05 mL·L^-1 Greenshield (citric-Greenshield), or 7 mg·L^-1 Kathon CG (citric-Kathon); 500 mL·L^-1 lemon/ lime soda and 500 mL·L^-1 water (soda); 10 mL·L^-1 household bleach, 20 g·L^-1 sugar and either 37 mL·L^-1 household lemon juice (lemon juice) or 6 mL·L^-1 household vinegar (vinegar); 10 mL·L^-1 Floralife Clear Professional (Floralife); or 10 mL·L^-1 Chrysal Clear Professional 2 (Chrysal), dissolved in tap water, which was also used as control without any added compound. Cut stems of all tested species had longest vase lives, when placed in citric-Al for 48 hours followed by shifting to tap water until termination. Lisianthus stems had greater number of buds opened when placed in soda. In marigold, preservative recipes had no effect on postharvest performance except vase life. In roses, stems placed in citric-Al or soda lost less fresh weights and all recipes effectively controlled bent neck in roses. In zinnia, use of soda, citric acid with either Greenshield or Kathon or Floralife maintained fresh weights of the stems. Moreover, citric-Al also controlled petal necrosis in zinnia.  When the same recipes formulations were used as a continuous vase solution until termination, cut lisianthus and marigold stems had longest vase life with citric-Greenshield or soda, which were statistically similar with citric- Kathon, commercial Floralife or Chrysal for lisianthus. In roses, Chrysal, Floralife, and citric-Al had longest vase life, while citric-Al proved detrimental for zinnia, where it had only 3.3 days vase life compared to 16.6 and 15.9 days with commercial preservatives. In summary, citric-Al proved best recipe for short term treatment, while for continuous application, soda or citric acid with either Greenshield or Kathon were effective for extending longevity of selected species. Among treatment durations, continuous vase application had longer vase life than short-term application. Moreover, treatments containing household bleach and vinegar were generally detrimental and had higher solution pH and EC, which not only reduced vase life, but also enhanced microbial contamination.