Does the raised bed have a solid bottom? If not, it is not a container and does not require a potting soil. You just need mostly garden soil and a small percentage of organic matter, like compost. If no extra garden soil (aka, "dirt") available, then purchased bag or bulk topsoil will work with the addition of the compost. IME, you never want to use vermiculite in a raised bed and I also discourage its use in containers. It adds nothing to a raised bed soil mix, is unnecessarily expensive and once fully saturated with water, will collapse and compress, leaving behind a soggy mess.

Do not listen to your nursery's recommendations!! They don't have a clue and using the mix they suggest is just going to leave you with an excessively acidic sludge!!

The bed is open to the ground below. I will avoid using vermiculite. Thanks for your help!

A large % of "recipe" suggested by the local nursery will gas off and disappear each year, and you'll have trouble keeping up with how much/often you'll need to water. While the soil you fill the beds with doesn't necessarily to be native topsoil, it should have large mineral fraction. My beds are mainly filled with sand, Turface, reed/sedge peat, and pine bark.

Pam's recommendation for topsoil with 5-10% OM should do very nicely. Pine bark breaks down slowly, so won't create a situation that immobilizes nitrogen - your peat/compost/vermiculite mix will, unless the compost is finished.

Al