Strawberry production in tropical and subtropical climates has been adversely affected by rising temperatures and reduced cooling periods, leading to a decrease in flower induction and overall yield. This experiment aimed to investigate the effects of root zone cooling on short-day strawberry plants cultivated under evaporative greenhouse conditions. The cooling methods employed included of four root zone cooling treatments: normal water dripping (NWD), cold-water (10 °C) dripping (CWD), cold-water dripping plus cold-water pipe (CWD + CWP), and normal water dripping plus cold-water pipe (NWD + CWP) embedded within the growing media. The results indicated that the CWD + CWP treatment was particularly effective, reducing RZT by approximately 2 °C compared to other treatments, thereby promoting both vegetative and reproductive growth, particularly in the ‘Akihime’ strawberry. In the absence of root zone cooling, ‘Akihime’ and ‘Pharachatan 88’ were still capable of producing flowers and yield, whereas ‘Pharachatan 80’ was not. In addition, ‘Pharachatan 80’ was affected by CWD + CWP which showed the highest levels of total phenolic compound, total anthocyanin, and total vitamin C among all treatments. It can be concluded that reducing the root zone temperature through the integrated application of cold-water dripping and embedded cold-water pipes in the growing media can enhance the growth and development of short-day strawberry plants cultivated under evaporative greenhouse conditions in a tropical climate.

Climate change has significantly impacted the flowering patterns of strawberry plants cultivated under typical environmental conditions, which conventionally require low temperatures to induce flowering. This study aimed to investigate the effects of cold-water irrigation on the growth and development of strawberries grown in a hydroponic system. The experiment was conducted in an uncontrolled greenhouse environment at the Faculty of Agriculture, Chiang Mai University, Thailand. A factorial arrangement of 2 × 2 in a completely randomized design was used, consisting of two root-zone cooling temperatures (cold water temperature at 10°C ± 1°C and ambient temperature water at 26°C ± 1°C) and two strawberry cultivars (‘Pharachatan 80’ or ‘P80’ and ‘Akihime’), with five replications. The results revealed that cold water temperature significantly enhanced vegetative growth parameters, including plant height (26.59 cm), canopy size (28.97 cm), leaf length (9.07 cm), leaf width (8.17 cm), petiole length (25.15 cm), root length (48.31 cm), and leaf number (8.36 leaves) compared to ambient temperature water. However, no significant interaction between cooling temperatures and strawberry cultivars was observed regarding vegetative growth. Conversely, a significant interaction between two factors was observed in flowering characteristics. The ‘Akihime’ cultivar produced a significantly higher number of flowers (10.64) under cold water conditions compared to ‘P80’ (6.13). Despite differences in flower number, no significant variation was observed in the number of fruits between the two cultivars; however, cultivar ‘P80’ exhibited superior fruit quality characteristics compared to ‘Akihime'. Notably, neither cultivar flowered under ambient temperature water conditions. These findings indicate that cold-water irrigation substantially promotes vegetative growth and effectively induces flowering in hydroponically grown strawberries under the uncontrolled environment of a greenhouse, highlighting the potential application of hydrocooling to enhance strawberry productivity, especially in regions increasingly impacted by rising temperatures due to climate change. Significance of this study: What is already known on this subject? In recent years, climate change has caused unpredictable weather patterns, leading to agricultural challenges in Thailand. Rising temperatures, shorter winters, prolonged summers, irregular rainfall, and increased pests and diseases have negatively affected strawberry flowering under natural conditions, which rely on cold temperatures for floral induction, especially in tropical climates. What are the new findings? These findings demonstrate that cold-water hydroponics significantly enhances the vegetative growth, root development, and flowering of strawberries under tropical climates. This study supports the potential application of hydrocooling as a method to improve strawberry cultivation, particularly in regions affected by rising temperatures due to climate change. What is the expected impact on horticulture? The findings from this research shall serve as a guideline for inducing strawberry flowering in Thailand and potentially extend their off-season production in hydroponic systems.