diff --git a/pkgs/by-name/pi/pick/package.nix b/pkgs/by-name/pi/pick/package.nix
index b6e8d6390302..aa00357abe68 100644
--- a/pkgs/by-name/pi/pick/package.nix
+++ b/pkgs/by-name/pi/pick/package.nix
@@ -18,7 +18,7 @@ stdenv.mkDerivation (finalAttrs: {
 
   buildInputs = [ ncurses ];
 
-  PREFIX = placeholder "out";
+  env.PREFIX = placeholder "out";
 
   meta = {
     inherit (finalAttrs.src.meta) homepage;