To test the effect of a substrate made from kitchen waste compost rather than partial peat on the growth of pak choi (Brassica chinensis L.). In indoor pots, four substrates were prepared by volume: 80% peat + 20% vermiculite (T1), 70% peat + 10% kitchen waste compost + 20% vermiculite (T2), 60% peat + 20% kitchen waste compost + 20% vermiculite (T3), and 50% peat + 30% kitchen waste compost + 20% vermiculite (T4). Soil was used as a control in the studies. The physicochemical properties of the four substrates, and the seed germination, growth, and quality of pak choi were all investigated. The results showed that the addition of kitchen waste compost increased the pH, EC, and bulk weight of the substrates while decreasing the aeration porosity. The addition of kitchen waste compost considerably enhanced the alkaline nitrogen, effective phosphorus, fast-acting potassium, and organic matter content of the substrates. Overall, the 70% peat + 10% kitchen waste compost + 20% vermiculite cultivation substrate formulation had a substantial effect on the quality indices of pak choi, delivering better growth results than soil. On the basis of this study, it is suggested that the cultivation substrate employing kitchen waste compost be optimized in order to further reduce the amount of peat utilized.