Garden Waste Compost Tea: A Horticultural Alternative to Promote Plant Growth and Root Traits in Tomato (Solanum lycopersicum L.) Plants

The application of garden waste compost teas (CTs) in sustainable agriculture constitutes a biostimulant and environmentally friendly alternative. The purpose of this work was to study the physicochemical properties of three CTs prepared with different brewing processes (CT1, CT2, and CT3) immediately after extraction and six months later to determine whether those properties changed over time and evaluate the effect of CT application on tomato (Solanum lycopersicum L.) plant growth. The brewing process had a significant effect on the extracts' chemical composition, while long-term storage did not lead to significant differences. The most energy-efficient CT was evaluated in a pot and in vitro assays by measuring plant growth parameters and root traits. CT1 directly supplied to the substrate increased the leaf number, plant height, and dry weight of tomato plants compared to the control and foliar treatments, whereas no significant differences were found among foliar treatments. In terms of the effects of CT application on root development, the results of the in vitro assays showed that CT supply enhanced the primary root length, lateral root number, and root fresh weight while decreasing shoot height and weight in 10-day-old tomato seedlings. From an agronomic standpoint, this study contributes new insights regarding the storage stability of CT and its impact on tomato plant growth.