What kind of soil do I use in a raised bed?

by Freda
(Southern Il USA)

I want to make a garden in my backyard in an area that used to be a gravel driveway. I am going to try a raised bed, but I'm not sure if I should use topsoil, garden soil or commercial potting mix. I also wonder if worms will be able to get to my garden with all the rock underneath. Would it be a good idea to put some worms in there myself? I live in zone 5/6 (St. Louis, Mo. area)

Doug says that normally we use a high-quality topsoil in a raised bed if that bed is in contact with the underlying soils. In other words, if the plants in that bed can put their roots down into the regular soil level, then a high-quality soil is the best thing you can use.

Will worms be able to get there? Probably - as long as the gravel isn't fully concrete. But it wouldn't be their first choice I'm sure. Let me suggest you have that gravel area "dug up" with a machine to either loosen up the gravel, replace it with soil, or loosened up and soil added to make it a better place for your plant roots to colonize (that would be my concern rather than the worms). Then build your raised beds on top of something that's going to encourage plant growth rather than discourage it.

You'll be happier in the long run rather than trying to patch up a growing bed over top of an area that's pretty hostile.

My .02. :-)