Spent Coffee Ground Compost as an Alternative Substrate to Peat Moss for Greenhouse Plant Production

Peat moss (PM) is the most commonly used plant substrate for greenhouse production; however, as PM extraction causes peatland depletion, the demand for alternative substrates to PM has increased. Spent coffee grounds (SCG), which are organic waste massively generated worldwide, have high concentrations of nutrients and organic matter and are considered an excellent partial substitute for PM. Hence, in this study, SCG compost (SCG-C) was developed by preparing different mixtures with cow manure (CM), which served as an additive to improve SCG degradability. The compost mixture consisting of 75% SCG and 25% CM satisfied all the plant growth parameters specified by Mexican regulations. Radish plants cultivated on a growing medium with 25% SCG-C exhibited optimal growth. Similarly, the addition of 25% SCG-C in PM positively affected the growth rates of tomato, jalapeño chili, serrano chili, and lettuce seedlings. Therefore, SCG-C is suitable for PM enrichment and production of plants.