We’ve seen far too many raised beds filled with “potting mix” from a landscape supply company and unhappy plants and unhappy gardeners. Landscape supply mixes are often high in salts and high in pH and completely unbalanced in nutrients. It is better to start filling a raised bed with a good topsoil so that there are adequate minerals for growing plants, then add a diverse high quality organic materials to build a home for soil biology. We have a number of customers who build their own planting mix using OrganiCalc to balance the minerals and they get very good results.
You can put together your own raised bed planting mix using our handy calculator to figure out the right amount of each ingredient. That will get your soil in the ballpark. Then (and this is the key) get the soil tested and use OrganiCalc to balance the minerals. If you are going to spend all this time and money growing vegetables, why not do it right?