What are you going to use for soil in the planters?
Bagged dirt, of any kind is not like natural soil, the critters that make it work by nature are not there.
Heat will affect a raised planter differently than in ground, it get heated from all sides, not just the top, therefore; watering is different from the grou.nd, etc., etc., etc.
Read (more than one, as many as you can find) about planters, especially in your area.