diff --git a/molecule/specs/skel.py b/molecule/specs/skel.py
index 117a767..37ff8dd 100644
--- a/molecule/specs/skel.py
+++ b/molecule/specs/skel.py
@@ -112,7 +112,7 @@ class GenericExecutionStep:
         os.environ['RELEASE_STRING'] = self.metadata.get('release_string', '')
         os.environ['RELEASE_VERSION'] = self.metadata.get('release_version', '')
         os.environ['RELEASE_DESC'] = self.metadata.get('release_desc', '')
-        os.environ['PRECHROOT'] = self.metadata.get('prechroot', '')
+        os.environ['PRECHROOT'] = ' '.join(self.metadata.get('prechroot', []))
 
     def setup(self):
         """