Comparison of growth and yield in leaf lettuce cultivated in different root media in a cold plastic greenhouse

This trial was conducted in a cold greenhouse to compare the growth and yield of leaf lettuce cultivated in six different root media with a nutrient solution prepared in the department. The trial included six different root media (peat, cocopeat, perlite, expanded clay, pumice, and tea waste) and the leaf lettuce variety "Basilic" (Lactuca sativa var. crispa). The seedlings were sourced from seedling companies and were grown in peat. Seedlings were planted in 5-liter bags containing different root media. The experimental design was a randomized block design, consisting of 6 root media and 3 blocks. Accordingly, there were 18 plots (6x3=18), with two plants per plot, totaling 36 plants in the experiment. The average plant height was 15,97 cm for peat, 15,93 cm for cocopeat, and 11,53 cm for tea waste. At the end of the experiment, the average plant diameter was 14,73 cm for peat, 14,88 cm for cocopeat, and 12,85 cm for tea waste. In terms of average leaf count, cocopeat had the highest at 20,17 leaves, followed by peat at 18,33 leaves, while tea waste averaged 12,5 leaves. The marketable plant weight averages were 232 g for peat, 207,67 g for cocopeat, and 150 g for tea waste. The values for expanded clay, perlite, and pumice were similar to each other. The results indicate that peat and cocopeat media provided the highest yield and plant growth in leaf lettuce production, while tea waste exhibited the lowest performance. The tea waste medium was deemed unsuitable due to various factors negatively affecting plant growth, such as the presence of fungus gnats (from the Sciaridae family) and white rot (Sclerotinia sclerotiorum) disease. The peat and cocopeat media demonstrated superiority in parameters such as marketable plant weight, leaf count, and plant height compared to other root media. However, in addition to yield and growth, the cost of the root media should also be considered. Although the tea waste medium is not suitable for yield and growth, it is suggested that tea waste could be made usable in agriculture through controlled mixing with different materials due to its lower cost.