After 15 years of research by the USDA and five years of development and field testing by TGS, the TGS technique for growing blackberries successfully in Hardiness Zones 4a-6b has been perfected. The following financial projections are based on a 10-acre planting using the TGS system. As you’ll see, the parameters used are conservative. It’s also important to note that these are examples; a thorough study and analysis must be conducted to arrive at an accurate projection for each application and location.