Evaluating Silicon Application Strategies for Sweet Basil Growth and Postharvest Chilling Injury Alleviation

The cold sensitivity of sweet basil often results in unmarketable chilling injury (CI) symptoms and a shorter shelf life under the low temperatures typically used to maintain most fresh produce during transportation and storage. Silicon (Si) treatments have been observed to alleviate these symptoms and provide other benefits during cultivation. This study tested different Si application strategies on basil plants to determine their efficacy at reducing CI symptoms and improving growth, and whether efficacy is influenced by dose–response or Si content in leaf tissues. Across four trials, preharvest treatment solutions containing potassium silicate or monosilicic acid were applied to potted basil at Si rates of 0, 50, 100, 150, and 200 mg/L through either regular rootzone fertigation or weekly foliar spray. There were no significant improvements in growth found at harvest. Although the median shelf life during cold storage at 4 °C ranged between 17 and 24 days for all groups, exceeding known estimates for untreated basil, there were no significant improvements compared to the controls. Drought stress could have been a contributing factor that hardened controls against chilling even without Si applications. Further investigations are necessary to determine the sole effects of Si applications on basil.