Can you cast wall type spells in mid air?

[Dwarmaj]

Can you cast Wall of Fire, Wall of Force, Wind Wall, or Blade Barrier in mid air?

I always thought you had to cast them on the ground or some other horizontal surface.

 

[Crothian]

they have to be anchored on the ground

 

[dcollins]

From the PHB Magic chapter:

A creature or object brought into being or transported to your location by a conjuration spell cannot appear inside another creature or object, nor can it appear floating in an empty space. It must arrive in an open location on a surface capable of supporting it. (PHB ch. 10: "Schools of Magic: Conjuration")

Edit: Of course, that doesn't actually provide an answer, since none of the spells in question would seem to need any "support" in the first place.

 

[Rashak Mani]

I think Wall of Force isn't included... at least logically speaking.

The 3.0 Version could even be used to trap flying creatures....

 

[UltimaGabe]

None of those spells need to be anchored to anything. None of them are physical barriers with weight, and therefore would be just as usable in mid-air as on the ground. Also, a Blade Barrier wouldn't do much help on the ground, considering anything it was anchored to would be taking damage every round.