Description of Invention
As the shortage of cultivating land and the advantages of preventing the disease caused by soil salinity accumulation and pests in soil, soilless cultivation like hydroponic is widely used. Recently, researchers found that cultivating lettuce using hydroponic system may result in 40% larger lettuce compared to soil-based system. By having hydroponics system in greenhouse that human-controlled, sustainable production is promised since climate or disaster issues can be avoided. Growth indices in lettuce including fresh weight, dry weight, diameter, height and leaf area are the important variables in growing lettuce and ensuring the quality.