What would be a good soil mix for a raised bed?
Raised bed soils should be light and well-drained. An excellent soil mix can be prepared by mixing equal parts topsoil, organic matter (well-rotted manure, compost, or peat), and coarse sand.
Before filling raised beds, remove the grass sod (if present) and work up the existing soil with a rototiller or spade. Add a few inches of the soil mix, then incorporate it into the existing soil. Continue to add and incorporate additional soil mix until the raised bed is filled. Incorporating the soil mix into the existing soil prevents the formation of distinct layers in the raised beds. Distinct layers of soil impede water movement and discourage root growth.