diff --git a/cmake/set_up_FFTW.cmake b/cmake/set_up_FFTW.cmake
index 29e494e901e1f8712f9ed75e90fa079dbf00e7d5..d6d33c0ae79649925f49de1bedd4220694955528 100644
--- a/cmake/set_up_FFTW.cmake
+++ b/cmake/set_up_FFTW.cmake
@@ -50,5 +50,8 @@ else()
       PkgConfig::FFTW3F)
   endfunction()
 
-  return(PROPAGATE FFTW3_INCLUDE_DIRS)
+  get_directory_property(hasParent PARENT_DIRECTORY)
+  if (hasParent)
+    return(PROPAGATE FFTW3_INCLUDE_DIRS)
+  endif()
 endif()