Sunshine Mix #1 - #4 have to do with the amount of aeration agents that have been added to the soil. Here is a link
to SunGro Horticulture's web site with a description of each product.
Sunshine Mix #1 has less aeration aggregates than Sunshine Mix #4
SunGro Holticulture also is the parent company of 'Black God' potting soil. The main SunGro plant for the Western US is located in Hubbard, Oregon.
Sunshine Mix (all flavors) cost $25.00 for the 3.8 cf. bales.