Abstract Introduction: “Ant gardens'' are ant nests located at different heights on trees on which vascular epiphytic plants that have been transported and sown by ants have germinated. Although this mutualistic relationship has been studied in humid tropical ecosystems, information on other tropical and Colombian ecosystems is scarce. Objective: To characterize the distribution, building, diversity, demography and phenology of ant gardens in dry tropical forest. Methods: In January and February, 2018, we identified 170 ant gardens on a 100x5 m transect on the banks of the Quesada River, Colombia, and in adjacent secondary dry premontane transitional forest; we monitored changes, for gardens and plants, in 28 of them, every two weeks (March 2018-February 2019). Results: The gardens, built by Azteca ulei, were aggregated near water bodies; had 10 species of epiphytes and were on 13 tree species. Larger gardens had more epiphyte species. Some epiphytes had a bimodal phenological pattern. Less seedlings become established in the dry season, and less adults remain in the gardens. Garden characteristics benefit both epiphytes and ants. Conclusions: The gardens built by A. ulei have ecological characteristics that favor the germination, establishment, and reproduction of diverse epiphytes in this dry tropical ecosystem, including aggregation near water flows.