Peat is used in various fields, from energy sources to fertilizer substrates. Peat bogs account for 3% of the earth's surface and represent a significant natural environment and carbon sink. Latvia is one of the European countries with the highest percentage of them and peat extraction plays an important role in the national economic market. Thus, the peat sector must be sustainably managed to regulate exploitation. In this context, this study's objective is to evaluate the overall environmental impact of the peat product chain. The tool used is a Life Cycle Assessment analysis (LCA), using a database made with primary data from a Latvian peat company and secondary data from a life cycle inventory database (Ecoinvent v3.7.1). The functional unit chosen is 1 m3 of peat substrate made for professional and non-professional horticultural use, a reference that consistently compares other standard substrates, namely coir pith and rock wool. The system boundaries include all the procedures from peat extraction to the product's end-of-life. Results of the study expressed with an ecological score (i.e., Pt) show that the stage that produces the most significant impact is that of the distribution of the final product for Human health (2.3 mPt), Climate change (1.39 mPt), and Resources (1.48 mPt) indicators and it is related to use of the diesel fuel. While for the Ecosystem quality indicator is peat extraction (1.59 mPt) and it is connected to the peat bogs opening. From the comparison with other alternative substrates for horticultural use, it has been concluded that coir pith has the highest impact (48.51 mPt), followed by rock wool (10.6 mPt) and peat (6.79 mPt).