diff --git a/tools/selftest.js b/tools/selftest.js
index 7e2ad61f80..b949522e90 100644
--- a/tools/selftest.js
+++ b/tools/selftest.js
@@ -611,6 +611,8 @@ _.extend(Sandbox.prototype, {
     var env = _.clone(self.env);
     env.METEOR_SESSION_FILE = path.join(self.root, '.meteorsession');
 
+    env.METEOR_LOG = 'debug';
+
     if (self.warehouse) {
       // Tell it where the warehouse lives.
       env.METEOR_WAREHOUSE_DIR = self.warehouse;