Yes, over-fertilization damages greenhouse vegetables. Excessive nitrogen causes lush but weak growth susceptible to disease and pests. Salt buildup from too much fertilizer damages roots and interferes with water uptake. Split applications are safer than single large doses. Base dressing provides foundation nutrients while foliar feeding offers quick corrections. Controlled-release fertilizers minimize salt spikes. Always follow soil test recommendations and observe plant response. Symptoms of excess include dark green leaves, curled tips, and white crust on soil surface from salt accumulation.