With Bonsai you use special soil and substrates to grow the tree. Garden and potting soil, as you use it for bedding and pot plants, do not have the right properties to grow Bonsai well and healthily. Often these types of soil stay wet for too long or do not absorb the water properly. There are also trees that set specific requirements for the soil mix, such as the acidity of the soil. Different types of Bonsai soil are often mixed together. You do this to make optimal use of the positive properties of these different types of soil.