What potting medium is suitable for spring sword orchid seedlings?

The substrate formula for pot cultivation is: rotten wood or sawdust, rice husks 15%, soybean-sized crushed ore (orchid growers in mining areas had best use crushed ore, for aeration) or crushed stone, crushed brick or coarse river sand 20%, crushed charcoal 15% (or plant ash), mung bean-sized granular humus soil 50% (this formula refers to what is suitable locally; different regions should adjust the ratio according to conditions such as temperature and humidity). For ground planting, spread a 3-5 cm layer of sawdust or rice husks, rotten leaves, peanut shells, etc. on the prepared raised bed, then spread about 20 cm of culture soil. The culture soil is prepared as follows: small-finger-sized crushed stone about 20%, farmyard manure fermented for more than one year and sterilized by fire 5%, coarse river sand 15%, humus soil (the black surface soil from the mountains) 60%. (Qin Shaoping, Guangxi)