Vortex Potting Soil is perfect for Texas gardeners (brewed in Austin!) who want to start with an all-natural potting soil and customize their own mix with their favorite fertilizers. Vortex Potting Soil is a mix of our premium compost, mineral sand, Super Natural Expanded Shale, and perlite. It also features biozome, which further increases microbial activity in plants. Although great in pots of any shape or size, it is also an excellent option for raised beds or square foot gardens. 1.5 cubic square foot bag.