diff --git a/docs/env_vars.md b/docs/env_vars.md
index 59c8f078f..05f792f56 100644
--- a/docs/env_vars.md
+++ b/docs/env_vars.md
@@ -15,7 +15,8 @@ wlroots reads these environment variables
 * *WLR_RENDER_NO_EXPLICIT_SYNC*: set to 1 to disable explicit synchronization
   support in renderers.
 * *WLR_RENDERER_FORCE_SOFTWARE*: set to 1 to force software rendering for GLES2
-  and Vulkan
+  and Vulkan. for Vulkan software rendering, it is recommended to install the
+  vulkan-swrast package.
 * *WLR_EGL_NO_MODIFIERS*: set to 1 to disable format modifiers in EGL, this can
   be used to understand and work around driver bugs.