Lactic Acid Bacteria Serum as a Natural Farming Input: Effects on Vegetative Growth, Biomass Accumulation, and Reproductive Onset of Tomato (Solanum lycopersicum L.) under Pot Culture

Abstract

Natural farming systems in India increasingly rely on farm-made microbial inputs, yet few controlled studies have quantified how such preparations influence crop growth across a full cropping cycle. This study evaluated a lactic acid bacteria (LAB) serum, prepared from fermented rice-wash water and cow milk and stabilised with jaggery, as a soil-applied biostimulant for tomato (Solanum lycopersicum L.). A pot experiment was conducted in 50 grow bags divided equally between an untreated control and a LAB treatment irrigated with a 1:1000 dilution. Plant height, root and shoot length, leaf number, leaf area, fresh and dry weight, and flower and fruit counts were recorded at 15-day intervals from 15 to 105 days after sowing (DAS). The establishment lag in LAB-treated plants was observed at 15 DAS, but from 30 DAS, the LAB-treated plants started to outperform the control plants, and LAB plants were favored in 31 of 36 vegetative comparisons from 30 to 105 DAS. The highest responses were at 60 DAS, with fresh weight, number of leaves, and plant height showing 158%, 94%, and 33%, respectively, more than the controls. The treated plants also bloomed approximately 15 days earlier, set more fruits, and had fewer obvious signs of pests and stress. The findings support LAB serum as a low-cost natural farming input, pending replicated field validation.