Lettuce (Lactuca sativa L) is one of the backyard plants that plays an essential role in human
life. Despite the high demand for lettuce in the market, the produced yield doesn't always
match. The production of lettuce can be enhanced through fertilization. However, the
continuous and abundant use of inorganic fertilizers can have negative impacts on the soil
environment, prompting the need for a combination of kasgot (organic) and urea
(inorganic) fertilizers. This research aims to determine the most effective dosages of urea
and kasgot fertilizers on lettuce plant growth and yield. The research design used is a
Factorial Randomized Block Design (RBD), with two factors. The first factor: kasgot
fertilizer dosage with 3 levels (15 t/ha, 30 t/ha, 45 t/ha). The second factor: urea fertilizer
dosage with 3 levels (0 t/ha, 200 t/ha, 350 t/ha), and each treatment is repeated three times.
The research findings indicate that the application of kasgot fertilizer at a dosage of 30 t/ha
(100 grams of kasgot and 0 grams of urea) significantly influences the growth and yield of
lettuce, including plant height, leaf count, leaf area, fresh plant weight, and dry plant
weight. However, it doesn't significantly affect stem diameter, where urea dosage
differences have a significant impact on stem diameter. The interaction between kasgot and
urea dosages in lettuce cultivation is most effective in the K2U0 treatment for leaf area,
fresh plant weight, and leaf area variables. Additionally, the K2U0 composition provides
positive value from both economic and ecological aspects.