I'm guessing you're in the UK? In most (all?) of the US "Dirt" and "Soil" are used interchangeably in casual conversation, with "Dirt" actually being the more c

I'm guessing you're in the UK? In most (all?) of the US "Dirt" and "Soil" are used interchangeably in casual conversation, with "Dirt" actually being the more common. "Soil" is only more common when referring specifically to tilled soil, or bagged potting soil. But even those will often be refereed to casually as "Dirt".