Order 2016 Almanac Now - Get 3 FREE Gifts
Reporting
I wouldn’t be too concernedI wouldn’t be too concerned about the heat as the raised bed will shade the surface beneath, but I would be worried that the solid surface beneath the beds would cause problems with drainage. You would need to either break up or remove the concrete below the bed, or else make gaps in the sides of the bed for water to escape.

2015 Special Edition Garden GuideCooking Fresh with The Old Farmer's AlmanacThe Almanac Monthly Digital MagazineWhat the heck is a Garden Hod?