The physical properties of horticultural substrate are important for optimal plant growth. The physical properties should be properly maintained during the crop growing season for producing higher yield. This experiment was carried out to evaluate the physical properties of different mixtures from various raw materials as horticultural substrates. The mixtures at the different ratios of peatmoss, perlite and vermiculite subjected to 10:0:0, 8:2:0, 6:4:0, 4:6:0, 2:8:0, 0:8:2, 0:10:0, 0:6:4, 0:4:6, 0:2:8, 8:0:2, 0:0:10, 6:0:4, 4:0:6, 2:0:8, 2:6:2, 2:4:4, 4:2:4, 4:4:2, 6:2:2 and 2:2:6 were prepared and analyzed according to two methods of the European Standardization (EN) and Rural Development Administration (RDA). The optimum range of physical properties of a specific horticultural substrate can be predicted using physical-property-triangle. This triangle can also be used to convert a physical property from the EN method to that from the RDA method. Results showed that the mixture at a ratio of > 60% peatmoss, in most cases, is in the range of optimum physical condition for plant growth. We conclude that the developed physical-property-triangle can be suitable to suggest the optimum ratios of horticultural substrates used in this study.