Background and aims <p>Although facilitation is well established in ecological theory, facilitative interactions between plants in tropical rainforests remain underexplored. In coastal plain forests (Restinga forests), characterized by nutrient-poor acidic soils, overflow water from epiphytic tank bromeliads (ETBs) during rainfall elevates soil nutrient levels and pH. However, whether ETBs in the canopy facilitate seedling growth on the forest floor remains unknown. Here, we combined isotopic tracers with a fertilization experiment to investigate whether ETBs can enhance the nutrition and growth of a fast-growing species.</p> Methods <p>In a greenhouse, <i>Jacaranda puberula</i> (Bignoniaceae) seedlings were grown in Restinga forest soil and irrigated with either bromeliad tank water or rainwater. To trace nutrient transfer from bromeliads, we enriched their tank detritus with ¹⁵N. We then compared water nutrient concentrations, seedling performance, and leaf isotopic ratios between treatments.</p> Results <p>Bromeliad water contained higher concentrations of nitrogen, phosphorus, calcium, magnesium, sulfur, iron, and aluminum than rainwater. Leaf nitrogen isotopic composition of seedlings irrigated with bromeliad water more than doubled, and their mature leaves had 35% more potassium, 36% more phosphorus, 3% more iron, and 24% less manganese. These seedlings also produced nearly twice as many leaves as those irrigated with rainwater.</p> Conclusion <p>We provide experimental evidence that ETBs can facilitate the nutrition and growth of fast-growing terrestrial seedlings on dystrophic soils by creating nutrient-enriched soil patches. This discovery reveals a novel mechanism of facilitation between plants involving spatially distant individuals, and advances our understanding of the processes interconnecting canopy and soil compartments in tropical rainforests.</p>