diff --git a/README.markdown b/README.markdown
index d38176c..1a8d72a 100644
--- a/README.markdown
+++ b/README.markdown
@@ -91,6 +91,8 @@ Notifications (growl/libnotify) can be disabled with:
     $ guard --notify false
     $ guard -n false # shortcut
 
+Notifications can also be disabled by setting a `GUARD_NOTIFY` environment variable to `false`
+
 The guards to start can be specified by group (see the Guardfile DSL below) specifying the <tt>--group</tt> (or <tt>-g</tt>) option:
 
     $ guard --group group_name another_group_name
diff --git a/lib/guard.rb b/lib/guard.rb
index 2e1f869..12c35a9 100644
--- a/lib/guard.rb
+++ b/lib/guard.rb
@@ -16,7 +16,8 @@ module Guard
       @listener = Listener.select_and_init
       @guards   = []
 
-      Notifier.turn_off unless options[:notify]
+      options[:notify] = false if ENV["GUARD_NOTIFY"] == 'false'
+      options[:notify] ? Notifier.turn_on : Notifier.turn_off
 
       self
     end
diff --git a/lib/guard/notifier.rb b/lib/guard/notifier.rb
index 52204e2..27e92df 100644
--- a/lib/guard/notifier.rb
+++ b/lib/guard/notifier.rb
@@ -9,26 +9,32 @@ module Guard
     end
 
     def self.turn_on
-      @disable = nil
+      @disable = false
+      case Config::CONFIG['target_os']
+      when /darwin/i
+        require_growl
+      when /linux/i
+        require_libnotify
+      end
     end
 
     def self.notify(message, options = {})
-      unless @disable || ENV["GUARD_ENV"] == "test"
+      unless @disable
         image = options[:image] || :success
         title = options[:title] || "Guard"
         case Config::CONFIG['target_os']
         when /darwin/i
-          if growl_installed?
-            Growl.notify message, :title => title, :icon => image_path(image), :name => "Guard"
-          end
+          Growl.notify message, :title => title, :icon => image_path(image), :name => "Guard"
         when /linux/i
-          if libnotify_installed?
-            Libnotify.show :body => message, :summary => title, :icon_path => image_path(image)
-          end
+          Libnotify.show :body => message, :summary => title, :icon_path => image_path(image)
         end
       end
     end
 
+    def self.disabled?
+      @disable
+    end
+
   private
 
     def self.image_path(image)
@@ -46,24 +52,18 @@ module Guard
       end
     end
 
-    def self.growl_installed?
-      @installed ||= begin
-        require 'growl'
-        true
-      rescue LoadError
-        UI.info "Please install growl gem for Mac OS X notification support and add it to your Gemfile"
-        false
-      end
+    def self.require_growl
+      require 'growl'
+    rescue LoadError
+      @disable = true
+      UI.info "Please install growl gem for Mac OS X notification support and add it to your Gemfile"
     end
 
-    def self.libnotify_installed?
-      @installed ||= begin
-        require 'libnotify'
-        true
-      rescue LoadError
-        UI.info "Please install libnotify gem for Linux notification support and add it to your Gemfile"
-        false
-      end
+    def self.require_libnotify
+      require 'libnotify'
+    rescue LoadError
+      @disable = true
+      UI.info "Please install libnotify gem for Linux notification support and add it to your Gemfile"
     end
 
   end
diff --git a/spec/guard/notifier_spec.rb b/spec/guard/notifier_spec.rb
index 900684d..e09622c 100644
--- a/spec/guard/notifier_spec.rb
+++ b/spec/guard/notifier_spec.rb
@@ -4,53 +4,55 @@ describe Guard::Notifier do
   subject { Guard::Notifier }
 
   describe ".notify" do
-    before(:each) do
-      @saved_guard_env = ENV["GUARD_ENV"]
-      ENV["GUARD_ENV"] = 'dont_mute_notify'
-      subject.turn_on
+    before(:each) { subject.turn_on }
+
+    if mac?
+      if growl_installed?
+        it "uses Growl on Mac OS X" do
+          Growl.should_receive(:notify).with("great",
+            :title => "Guard",
+            :icon  => Pathname.new(File.dirname(__FILE__)).join('../../images/success.png').to_s,
+            :name  => "Guard"
+          )
+          subject.notify 'great', :title => 'Guard'
+        end
+      else
+        it { should be_disabled }
+      end
     end
 
-    if mac? && Guard::Notifier.growl_installed?
-      it "uses Growl on Mac OS X" do
-        Growl.should_receive(:notify).with("great",
-          :title => "Guard",
-          :icon  => Pathname.new(File.dirname(__FILE__)).join('../../images/success.png').to_s,
-          :name  => "Guard"
-        )
+    if linux?
+      if libnotify_installed?
+        it "uses Libnotify on Linux" do
+          Libnotify.should_receive(:show).with(
+            :body      => "great",
+            :summary   => 'Guard',
+            :icon_path => Pathname.new(File.dirname(__FILE__)).join('../../images/success.png').to_s
+          )
+          subject.notify 'great', :title => 'Guard'
+        end
+      else
+        it { should be_disabled }
+      end
+    end
+  end
+
+  describe ".turn_off" do
+    if mac? && growl_installed?
+      it "does nothing" do
+        Growl.should_not_receive(:notify)
         subject.notify 'great', :title => 'Guard'
       end
     end
 
-    if linux? && Guard::Notifier.libnotify_installed?
-      it "uses Libnotify on Linux" do
-        Libnotify.should_receive(:show).with(
-          :body      => "great",
-          :summary   => 'Guard',
-          :icon_path => Pathname.new(File.dirname(__FILE__)).join('../../images/success.png').to_s
-        )
+    if linux? && libnotify_installed?
+      it "does nothing" do
+        Libnotify.should_not_receive(:show)
         subject.notify 'great', :title => 'Guard'
       end
     end
 
-    describe ".turn_off" do
-      before(:each) { subject.turn_off }
-
-      if mac? && Guard::Notifier.growl_installed?
-        it "does nothing" do
-          Growl.should_not_receive(:notify)
-          subject.notify 'great', :title => 'Guard'
-        end
-      end
-
-      if linux? && Guard::Notifier.libnotify_installed?
-        it "does nothing" do
-          Libnotify.should_not_receive(:show)
-          subject.notify 'great', :title => 'Guard'
-        end
-      end
-    end
-
-    after(:each) { ENV["GUARD_ENV"] = @saved_guard_env }
+    it { should be_disabled }
   end
 
 end
diff --git a/spec/guard_spec.rb b/spec/guard_spec.rb
index f635a4f..bf3faa8 100644
--- a/spec/guard_spec.rb
+++ b/spec/guard_spec.rb
@@ -23,10 +23,22 @@ describe Guard do
         ::Guard.listener.should be_kind_of(Guard::Listener)
       end
 
+      it "should turn on by default" do
+        ::Guard::Notifier.should_receive(:turn_on)
+        ::Guard.setup(:notify => true)
+      end
+
       it "should turn off notifier if notify option is false" do
         ::Guard::Notifier.should_receive(:turn_off)
         ::Guard.setup(:notify => false)
       end
+
+      it "should turn off notifier if env[GUARD_NOTIFY] is false" do
+        ::Guard::Notifier.should_receive(:turn_off)
+        ENV["GUARD_NOTIFY"] = 'false'
+        ::Guard.setup(:notify => true)
+        ENV["GUARD_NOTIFY"] = nil
+      end
     end
 
     describe ".get_guard_class" do
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 1520849..f69ed16 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -15,6 +15,7 @@ RSpec.configure do |config|
   config.run_all_when_everything_filtered = true
 
   config.before(:each) do
+    Guard::Notifier.turn_off
     @fixture_path = Pathname.new(File.expand_path('../fixtures/', __FILE__))
   end
 
diff --git a/spec/support/gems_helper.rb b/spec/support/gems_helper.rb
new file mode 100644
index 0000000..2ccf7fe
--- /dev/null
+++ b/spec/support/gems_helper.rb
@@ -0,0 +1,13 @@
+def growl_installed?
+  require 'growl'
+  true
+rescue LoadError
+  false
+end
+
+def libnotify_installed?
+  require 'libnotify'
+  true
+rescue LoadError
+  false
+end
\ No newline at end of file