diff --git a/src/pretix/base/models/items.py b/src/pretix/base/models/items.py
index 2a49e06e11..780af9c732 100644
--- a/src/pretix/base/models/items.py
+++ b/src/pretix/base/models/items.py
@@ -631,7 +631,7 @@ class Item(LoggedModel):
         null=True, blank=True, max_length=16,
         verbose_name=_('Validity'),
         help_text=_(
-            'When setting up a regular event, or an event series with time slots, you typically to NOT need to change '
+            'When setting up a regular event, or an event series with time slots, you typically do NOT need to change '
             'this value. The default setting means that the validity time of tickets will not be decided by the '
             'product, but by the event and check-in configuration. Only use the other options if you need them to '
             'realize e.g. a booking of a year-long ticket with a dynamic start date. Note that the validity will be '
diff --git a/src/pretix/control/forms/item.py b/src/pretix/control/forms/item.py
index 2c8169a283..72c7c1afbc 100644
--- a/src/pretix/control/forms/item.py
+++ b/src/pretix/control/forms/item.py
@@ -614,6 +614,15 @@ class ItemUpdateForm(I18nModelForm):
 
         self.fields['free_price_suggestion'].widget.attrs['data-display-dependency'] = '#id_free_price'
 
+        self.fields['validity_dynamic_start_choice'] = forms.TypedChoiceField(
+            label=_("Start of validity"),
+            choices=(
+                ("False", _("Purchase date")),
+                ("True", _("Date chosen by customer")),
+            ),
+            coerce=lambda x: x == 'True',
+        )
+
         qs = self.event.organizer.membership_types.all()
         if qs:
             self.fields['require_membership_types'].queryset = qs
diff --git a/src/pretix/control/templates/pretixcontrol/item/index.html b/src/pretix/control/templates/pretixcontrol/item/index.html
index 55778b817c..0ce0c034ec 100644
--- a/src/pretix/control/templates/pretixcontrol/item/index.html
+++ b/src/pretix/control/templates/pretixcontrol/item/index.html
@@ -209,6 +209,7 @@
                             {% bootstrap_field form.validity_fixed_until layout="control" %}
                         </div>
                         <div data-display-dependency="#{{ form.validity_mode.id_for_label }}" data-display-dependency-value="dynamic">
+                            {% bootstrap_field form.validity_dynamic_start_choice layout="control" %}
                             <div class="form-group metadata-group">
                                 <label class="col-md-3 control-label">{% trans "Duration" %}</label>
                                 <div class="col-md-9">
@@ -231,8 +232,7 @@
                                     </div>
                                 </div>
                             </div>
-                            {% bootstrap_field form.validity_dynamic_start_choice layout="control" %}
-                            <div data-display-dependency="#{{ form.validity_dynamic_start_choice.id_for_label }}">
+                            <div data-display-dependency="#{{ form.validity_dynamic_start_choice.id_for_label }}" data-display-dependency-value="True">
                                 {% trans "days" as t_days %}
                                 {% bootstrap_field form.validity_dynamic_start_choice_day_limit addon_after=t_days layout="control" %}
                             </div>