Background and objective: This study was conducted to promote a companion plant for building-integrated urbanagriculture and determine appropriate spatial conditions for planting cherry tomatoes (Solanum lycopersicum) andnasturtiums (Tropaeolum majus), a companinon plant, in response to the increasing demands for eco-friendly agriculturalpractices in urban.
Methods: The growth and quality of cherry tomatoes (CTs) and nasturtiums achieved with different planting ratios wereanalyzed: CC (when only CTs were planted), C2N1 (ratio of CTs to nasturtiums: 2:1), C1N1 (1:1), C1N2 (1:2), NC (when onlynasturtiums were planted) on the rooftop and wall. A one-way ANOVA was used to evaluate the significance of test resultsbased on planting ratios, followed by Duncan's multiple range test at a 95% confidence level. Independent sample t-testswere conducted to examine the growth and quality of CTs between the rooftop and wall.
Results: Overall, CTs in CC showed significant growth compared to companion planting with nasturtiums. Among thetreatment plots, the CTs in C2N1 had the highest plant weight and sugar concentrations on the rooftop. Similar patternswere observed on the wall. When planted in a 2:1 ratio as a companion plant to CTs (C2N1), nasturtiums had larger leavesand flowers. In terms of leaf size, plant weight, fruit weight, and sugar content CTs appeared to grow better on the wall thanon the rooftop when planted with nasturtiums. For optimal CTs growth and quality, it is recommended to plant CTs in a 2:1ratio with nasturtiums on the wall.
Conclusion: Due to the distinctive spatial features of urban agriculture using buildings, specialized management strategiesfor different crops should be suggested. Further research should focus on a quantitative analysis of fruit and seed quality,as well as on a qualitative analysis to comprehensively understand the potential outcomes.