Composted Sewage Sludge as an Alternative Potting Media for Lettuce Cultivation

A study was conducted to evaluate the potential possibility of using composted sewage sludge (CSS) as an alternative potting media component to substitute for expensive peat (PE) in lettuce (Lactuca sativa L.) cultivation. Five different substrates were developed by changing the CSS and PE percentages in the growth medium. Percentages of CSS addition to PE were 0%, 15%, 30%, 50%, and 70% v/v, respectively. Growing media developed from CSS by substituting PE had plentiful physical and chemical properties and prominent contents of plant nutrients, mainly phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). The greatest growth and yield increments were achieved from the medium with 30% CSS and 70% PE of the total volume, respectively. The shoot fresh weight, shoot dry weight, root fresh weight, and root dry weight obtained from the medium with 30% CSS and 70% PE were increased by 56.53%, 43.93%, 29.46%, and 67.24%, respectively, compared to PE control.