Advancing Sustainability in Pelargonium Nursery Management: Scientific Exploration of an Innovative Prolonged Cold Storage System for Cuttings

Cold storage of pelargonium cuttings addresses the issue of nonoverlapping production seasons in Central Europe, where cuttings are harvested from stock plants in December, but rooting begins in mid-February/March. Here, we show an innovative system for cuttings storage using nature-based solutions. We compared post-delivery storage of unrooted cuttings in paperpots maintained in greenhouses (8/6 °C day/night) to standard rooting immediately after delivery. Key factors included genotype (Pelargonium zonale, P. peltatum, and hybrids), four delivery weeks (48–51), two growing seasons (2021 and 2022), and storage duration (up to 4 weeks). Genotype strongly influenced cold storage tolerance, with P. peltatum enduring storage for up to 4 weeks without significant loss of rooting efficiency, unlike P. zonale. The success of storage depended on stock plants’ quality and nutritional status: higher nitrogen content in 2022 cuttings compared to 2021 was associated with reduced rooting in P. zonale and hybrids. Neither delivery timing nor residual ethephon affected rooting outcomes after storage. This study demonstrates that storing pelargonium cuttings for up to two weeks using this method preserves quality while optimizing production efficiency by reducing nursery space, water, fertilizer, and pesticide use. This shift in production practices reduces per-unit costs and enhances the economic viability of bedding young plant producers.