diff --git a/src/server/farm.scm b/src/server/farm.scm
index 9ff45b4..58779d9 100644
--- a/src/server/farm.scm
+++ b/src/server/farm.scm
@@ -372,6 +372,12 @@
            (push-message player
                          (conc "Could not buy " unnormalized-crop ". Not enough credit."))
            #f)
+          ((and (eq? unnormalized-crop 'cows)
+                (= (- (player-asset 'cows player)
+                      (fold + 0 (map cdr (player-ridges player))))
+                   20))
+           (push-message player (conc "Could not buy " unnormalized-crop " because it would exceed maximum allowed on farm."))
+           #f)
           (else
            (let ((assets (player-assets player)))
              (set!
@@ -1698,9 +1704,6 @@
 ;; make sure two players can't have the same name
 ;; bug: harvest action multiplayer doesn't flow right for other players
 ;; info actions should look better
-;; limit to 20 cows
-;; don't give extra money for extra tractors
 ;; you can get $50 from harvest
-;; buy ifs with blank box
 ;; ran out of otbs
 ;; bug: new websocket messages should not reset IFS card selection