This mix has loads of nutrients, organic matter and minerals (including Charlie Charcoal) to help hold water.  Acid Concentrate is designed especially for acid loving plants that like a lower pH for optimum growth.  Use as a soil improver in very sandy soils. We recommend a ratio of 50:50. As a top up to existing beds, with a reasonable soil, it is fine to use it at a lower dilution rate.
Acid Concentrate is NOT a planting medium on its own. It must be dug into the top 10 - 30 cms of existing soil.