As the name implies, topsoil is the first layer of soil, usually about 2 to 8 inches above your natural soil bed. Your garden success depends on the nutrients, pH balance, water retention and aeration of this layer. Without a sufficient layer, your plants will struggle to survive, much less thrive.
It can be used to cover the ground, create new beds, borders or to provide a base for turf laying or sowing grass seed. In paved gardens where there is no access to soil, it can be used in raised beds for growing many plants, including vegetables.