You never should have gotten rid of your mineral soil. What you want is mineral soil with about 10% organic matter by weight or 30% by volume. Out of curiosity, what possessed you to get rid of the soil.

Organic matter, those leaves, are not soil. Soil is composed of the mineral portion, the sand, silt, and clay particles, and that organic matter. Sand is the largest soil particle and has large spaces between soil particles that allow both water and nutrients flow through fairly quickly. Silt is much smaller in size as is clay and both tend to clump tightly together and prevent flow of water and nutrients. In addition to providing needed nutrients the purpose of organic matter in soils is to fill in the spaces between the sand particles so moisture and nutrients stay available to roots and to separate the silt and clay particles so moisture, nutrients, and plants roots can find each other.
Out in the woods behind the house I find Ma Nature keeps the soil there with organic matter in the range of 6 to 8 percent in the top 6 inches of soil provided we humans do not disrupt that.

Here is a link that might be useful: Nutrients in tree leaves