How to mix soil for sowing flowers? A detailed guide to preparing seedling substrate

Moist, water-retentive soil: 6 parts ordinary soil, 2 parts river sand (or perlite sand), 2 parts high-quality humus (such as rotted soil from sawdust, peanut shells, leaves, etc.), and 1 part high-quality organic fertilizer; mix them together and it is ready. Dry, free-draining soil: 3 parts ordinary soil, 4 parts river sand (or perlite sand) with equal parts coarse and fine, 2 parts high-quality humus soil, and 1 part organic fertilizer; mix them together and it is ready.