Raised Garden Bed Mix is similar to potting mix. If you were to make your own raised garden bed soil mix, you could use 50% garden soil and 50% potting mix for a good drainage and aeration. Garden centers also make bagged soils specific to raised beds, making this the ideal choice.
Topsoil is not meant to be used for planting in your raised garden bed—it’s considered more of a soil conditioner and used to fill in gaps in in-ground gardens. Top soil is pulled from the top foot or so of the earth and can be made of just about anything depending on where it was pulled from. It is very dense and usually lacks proper nutrients.