Unless he can get a grip on something (cord, plant, etc [which you don't have]) youi'll be fine. Ensure that the glass from the dirt to the top is taller than the length of your scorpion and its tail. (They will balance on their tails to extend their length when climbing).
Likely, you'll be able to tell the moment he's out and exploring. I've never seen one not attempt a "glass climb" (they can't tell the glass is there, so they try to climb it). If he's not out in the first dozen attempts, you're probably solid.