Study of the Effect of Planting Schemes and Growth Regulators on Ice Salad Productivity

The article presents the results of a study evaluating the effects of planting patterns and growth regulator application on the productivity of Iceberg lettuce under open-field conditions in the Moscow Region. The research was conducted in 2025 on sod-podzolic medium loamy soil at AgroMix LLC in the Kolomna urban district. The object of the study was Iceberg lettuce (Lactuca sativa var. capitata) of Gavrish breeding. A two-factor field experiment was established to assess three planting patterns (30 × 30, 35 × 35, and 40 × 40 cm) and six treatment systems involving the growth regulators Epin-Extra and Zircon, as well as the biological product Fitosporin-M. A positive effect of growth regulators on seed quality, plant growth, and development was established. The highest germination energy and laboratory germination rate were recorded following the combined application of Epin-Extra. Planting pattern was found to have a significant effect on yield formation. The highest average yield of Iceberg lettuce (35.2 t/ha) was obtained with the 35 × 35 cm planting pattern. The application of growth regulators increased yield compared with the untreated control, with the greatest effect achieved through the double application of Epin-Extra, including pre-sowing seed treatment and foliar spraying during the growing season. An interaction between planting pattern and treatment application was demonstrated. The maximum yield of 38.2 t/ha was achieved when the 35 × 35 cm planting pattern was combined with the integrated application of Epin-Extra, resulting in a yield increase of up to 19% compared with the control treatment. The use of growth regulators improved marketable yield, increased head weight, and reduced nitrate accumulation. The results obtained allow recommending a cultivation technology based on a 35 × 35 cm planting pattern and double application of Epin-Extra for Iceberg lettuce production in the Moscow Region.