diff --git a/app/views/lectures/_lecture.html.erb b/app/views/lectures/_lecture.html.erb
index 3b00d81..67b1597 100644
--- a/app/views/lectures/_lecture.html.erb
+++ b/app/views/lectures/_lecture.html.erb
@@ -60,12 +60,13 @@
   </td>
 
   <td class="whitespace-nowrap px-3 py-4 text-sm text-gray-500">
-    <% if lecture.start_time.future? %>
+    <% joinable_time = lecture.start_time - 5.minutes %>
+    <% if joinable_time.future? %>
       <%= button_to "Prepare",
                     lecture_start_preparation_path(id: lecture.id),
                     class: 'action-button'
       %>
-    <% elsif lecture.start_time.past? && !lecture.attended? %>
+    <% elsif joinable_time.past? && !lecture.attended? %>
       <% start_label = if lecture.is_live? then
                          "Join"
                        else