Suitability of Apium graveolens L. var. secalinum Alef. to hydroponic cultivation for baby leaf production

Abstract

Consumers are increasingly seeking innovative, healthy foods rich in nutraceuticals, driving the search for new or underutilized leafy vegetables. Leaf celery (Apium graveolens L. var. secalinum Alef.), a promising candidate for new food sources, stands out from ribbed celery with its smaller size and enhanced aroma. It is gaining global interest due to its high concentration of bioactive compounds, but it is presently cultivated only on soil in restricted regions. Significant knowledge gaps still exist regarding optimal agronomic management for its hydroponic baby leaf production and post-harvest cold storage as a minimally processed product. The necessity of adopting hydroponic systems for ready-to-eat leafy salads requires specific studies on techniques and nutrient management for novel vegetables like leaf celery. This research, for the first time, investigates the feasibility of producing fresh-cut suitable leaf celery baby leaves using a hydroponic ebb-and-flow cultivation system. We studied the effects of two plant densities (615 and 947 plants m⁻²) and three nutrient solution concentrations (NS) (only water, half strength, and full strength) on leaf celery growth, yield, and postharvest quality over two growing seasons (S1: winter/spring and S2: spring/summer). The experiment included two mowings per season to test the plant's regrowth capability, with morphological, biochemical, and yield characteristics assessed after each. Leaves from the first mowing of each trial were tested via sensory analysis and evaluated for shelf-life following minimal processing and cold storage (21 days at 4 °C). This research provides essential, globally transferable data for sustainable Controlled Environment Agriculture (CEA) by quantifying the yield, nutritional stability, and post-harvest longevity of this novel crop across critical seasonal and resource management variables. Results showed higher total yields in S1 (5.25 kg m⁻²) compared to S2 (2.76 kg m⁻²) using the full-strength NS, with nutrient availability effects varying by season and density. The full-strength NS maximized total yield, while the half-strength NS achieved the highest NUE (35.6 g DW g−1 N in S1). Importantly, the baby leaves exhibited good vitamin and mineral content with consistent stability across growing seasons and mowings. Their sensory profile showed only minor differences between seasons, generally maintaining a good overall evaluation. Crucially, the leaves maintained a shelf-life exceeding 14 days across all tested treatments. Overall, leaf celery proved well-suited for hydroponic cultivation, yielding baby leaves with excellent shelf-life and nutritional quality, offering a viable high-value option for the fresh-cut market.