Can't keep a Milan flower alive? Mom uses this kind of soil and it blooms and fills the pot year after year, scenting the whole house

The Milan flower has a very long flowering period and can bloom many times a year, and when it blooms it is full of fragrance, so many people adore it. But many Milan growers say that every one they plant dies, which is really heartbreaking. As it happens, in Mom's hands, every pot of Milan she grows survives, and it blooms nonstop, and Dad always praises how fragrant Mom's Milan flowers are.
Many friends take a perfectly good Milan flower and grow it into a pitiful sight, and they all get terribly anxious. People say that to grow flowers you first grow the roots, and to grow roots you first grow the soil. Maybe everyone has overlooked the soil problem. In fact, most of those Milan flowers that were grown to failure had soil that had hardened and compacted, with no nutrients, so it is hard for the Milan flower to grow well.
Actually, every kind of flower likes a different soil mix, but loose, airy soil is every flower's beloved favorite. Mom likes to use black mountain soil, because it is on the acidic side and high in humus, which suits the Milan flower just right. If you prefer to use garden soil, you can also mix in some sand or leaf mold, which will make it more airy.
In addition, some people like to pour leftover milk and soy milk into the flower pot, thinking it saves waste and adds nutrients, but they overlook the fact that this makes the soil clump easily and breed pests. When Mom gives her Milan flower a boost, she always uses a general-purpose organic nutrient solution, which can increase the activity of the soil and also nourish the roots, so the leaves are all emerald green and glossy.
If the soil is really too hard, then it is better to change the soil. You can remove 1/3 of the surface soil that has turned white and hard, then fill in black mountain soil or homemade soil, and just let it recover as normal. In some regions the winter is rather cold, and the Milan flower still needs to be moved indoors to overwinter. You can also use plastic pots, which are very light and easy to carry, saving effort when moving them.
Once the soil problem is solved, watering becomes much easier too. Give it plenty of sun as usual and a bit of fertilizer, and the Milan flower will bloom like crazy. Before the flowering period, Mom usually gives the Milan flower a sour drink every 10 days, which is a purely plant-fermented organic nutrient solution, feeding plants with plants, safe and ecological. The Milan flowers really are abundant and fragrant, and Mom is absolutely delighted.
With Mom around, there is flower fragrance to enjoy every year, and it feels so good. What kind of soil do you think is best for growing Milan flowers?