Influence of Growing Media and Fertilizer Management on Strawberry Performance Under Tropical Greenhouse Conditions

This study evaluated the effects of growing media and fertilizer applications on greenhouse strawberry cultivars ‘Pharachatan 80’ and ‘US Jumbo’ using a 4 × 3 factorial in CRD with five replications. Growing media comprised sand (S), coconut coir dust (C), and cow manure (M) in varying ratios (1:1, 1:1:1, 1:1:2, and 1:1:3 v/v), paired with no chemical fertilizer (NCF), a half-recommended dose (½ RDCF), or a full recommended dose of chemical fertilizer (RDCF). Results revealed that unamended substrate (S:C = 1:1 v/v) under NCF severely constrained crop performance. Conversely, integrating cow manure with chemical fertilizers significantly enhanced vegetative growth and yield attributes. Specifically, S:C:M 1:1:1 v/v combined with ½ RDCF optimized total marketable yield, increased the proportion of Grade 2–4 fruits, and improved fruit quality across both cultivars. However, elevated temperatures in tropical lowland greenhouses constrained fruit enlargement, resulting in ≥70% Low-Grade fruits (<7.0 g). Correlation and principal component analyses confirmed that balanced root-zone management mitigates severe nutrient stress. Overall, S:C:M 1:1:1 v/v with ½ RDCF represents the most effective strategy for tropical greenhouse strawberry cultivation, although implementing microclimate cooling or exogenous biostimulants remains necessary to overcome high-temperature limitations.