diff --git a/golem_season/models/golem_season.py b/golem_season/models/golem_season.py
index be94f666..ebdf2a50 100644
--- a/golem_season/models/golem_season.py
+++ b/golem_season/models/golem_season.py
@@ -30,7 +30,7 @@ class GolemSeason(models.Model):
     name = fields.Char('Season name', copy=False)
 
     membership_id = fields.Many2one('product.template', 'Membership type',
-                                    domain="[('membership', '=', True)]" )
+                                    domain="[('membership', '=', True)]")
 
 
     member_counter = fields.Integer('Counter for member number generation',
@@ -38,6 +38,16 @@ class GolemSeason(models.Model):
     date_start = fields.Date('Period start')
     date_end = fields.Date('Period end')
 
+    @api.onchange('membership_id')
+    def _onchange_season_dates(self):
+        """ Sets defaults dates according to membership type """
+        for activity in self:
+            if activity.membership_id:
+                if not activity.date_start:
+                    activity.date_start = activity.membership_id.membership_date_from
+                if not activity.date_end:
+                    activity.date_end = activity.membership_id.membership_date_to
+
     @api.constrains('date_start', 'date_end')
     def _check_period(self):
         """ Check if end date if after start date and if there is no conflict