Improving hydration and vase life of cut Zinnia

Abstract

Zinnia (Zinnia elegans Jacq.) is a commercially important species in the cut flower industry that has several postharvest challenges including hydration, cold storage, and seasonality. The purpose of this work was to increase vase life of cut zinnia by assessing hydration, chilling sensitivity and storage temperatures, and environmental impacts incurred by harvest date. The negative effects of allowing zinnia ‘Benary Giant Deep Red’ stems to dry up to 4 h after hydrating were negated by recutting stems and removing 2.5 cm of the stem. However, if zinnia stems did not dry out, then recutting had either no effect or a negative impact. Zinnia stems did not rehydrate if allowed to dry for 24 h or more and recutting various amounts from stem ends before placing in vases demonstrated no significant effect on vase life, nor did varying the number of stems per vase. Vase life increased by 2.2 d when stems were stored in a 0.01845 mL L−1 sodium hypochlorite solution versus tap water. Postharvest quality of zinnia was affected by storage temperature such that the longest vase life of 13.0 d occurred when stems were stored for 5 h at 5 °C followed by 2 d storage at 1 °C. As storage temperature increased, zinnia vase life decreased, with the shortest vase life of 6.5 d occurring when stems were stored for 48 h at 20 °C. Vase life continually declined when zinnia stems were harvested every 2 wks from 27 July to 19 Oct. The use of floral preservatives increased vase life late in the harvest season but was not comparable to the extended vase life obtained earlier in the season. Zinnia vase life increased by 2.1 d with the use of a floral preservative (Floralife® Professional) as a 20 h pulse solution in lieu of tap water only. The main findings of this research show that zinnia stems can tolerate a short period of desiccation, while storing stems in a floral preservative and incorporating a brief cold storage period of 1–3 d at 1–5 °C increased vase life. Chilling sensitivity was not observed. Conversely, vase life was observed to be negatively correlated with late season harvesting.