Not original poster, but agree completely with the solution posted. To add to this, the fundamental problem is that the garden soil will always hold water and it will slowly leech through the concrete, if you can't seal it. You need to create a space between the concrete and the soil in order for the water to flow properly - hence the gravel solution. The only thing that I would add is that you may want to place landscaping cloth on the boundary between the gravel and soil, and consider whether a french drain would be an appropriate install. Please note that, you don't need to get a french drain wrapped in landscaping cloth as the purpose of the cloth is to keep the soil separate from the drain...and that's what the gravel is for...and you don't want soil getting into the gravel (otherwise you've just created New England's soil) hence the proper place for the cloth is between the gravel and soil.

The acos can be useful for the roof's dripline, if you don't have properly functioning gutters or if you can't regrade the soil and the water is pooling on the surface at the building.