diff --git a/addons/mrp/models/mrp_production.py b/addons/mrp/models/mrp_production.py
index 22819090b4b..ca5a20b1d20 100644
--- a/addons/mrp/models/mrp_production.py
+++ b/addons/mrp/models/mrp_production.py
@@ -99,6 +99,11 @@ class MrpProduction(models.Model):
         states={'done': [('readonly', True)], 'cancel': [('readonly', True)]})
     date_start = fields.Datetime('Start Date', copy=False, index=True, readonly=True)
     date_finished = fields.Datetime('End Date', copy=False, index=True, readonly=True)
+    date_start_wo = fields.Datetime(
+        'Planning Start Date', copy=False, readonly=True,
+        states={'draft': [('readonly', False)], 'confirmed': [('readonly', False)]},
+        help="The work orders will be planned based on the availability of the work centers starting from "
+        "this date. If emtpy, the work orders are planned as soon as possible.")
     bom_id = fields.Many2one(
         'mrp.bom', 'Bill of Material',
         readonly=True, states={'draft': [('readonly', False)]},
@@ -615,7 +620,7 @@ class MrpProduction(models.Model):
         return True
 
     def _get_start_date(self):
-        return datetime.now()
+        return self.date_start_wo or datetime.now()
 
     def plan_workorders(self):
         WorkOrder = self.env['mrp.workorder']
@@ -661,7 +666,11 @@ class MrpProduction(models.Model):
                         start_date = from_date + relativedelta(minutes=duration)
 
     def button_unplan(self):
-        self.mapped('workorder_ids').write({'date_planned_start': False, 'date_planned_finished': False})
+        if any(wo.state == 'done' for wo in self.workorder_ids):
+            raise UserError(_("Some work orders are already done, you cannot unplan this manufacturing order."))
+        elif any(wo.state == 'progress' for wo in self.workorder_ids):
+            raise UserError(_("Some work orders have already started, you cannot unplan this manufacturing order."))
+        self.workorder_ids.unlink()
 
     @api.multi
     def _generate_workorders(self, exploded_boms):
diff --git a/addons/mrp/tests/test_workorder_operation.py b/addons/mrp/tests/test_workorder_operation.py
index 1a3f1a82b9b..fcfce68733d 100644
--- a/addons/mrp/tests/test_workorder_operation.py
+++ b/addons/mrp/tests/test_workorder_operation.py
@@ -598,3 +598,29 @@ class TestWorkOrderProcess(common.TransactionCase):
         # Check that the workorder is planned now and that it lasts one hour
         self.assertAlmostEqual(workorder.date_planned_start, datetime.now(), delta=timedelta(seconds=10), msg="Workorder should be planned now.")
         self.assertAlmostEqual(workorder.date_planned_finished, datetime.now() + timedelta(hours=1), delta=timedelta(seconds=10), msg="Workorder should be done in an hour.")
+
+    def test_04b_test_planning_date(self):
+        """ Test that workorder are planned at the correct time when setting a start date """
+        # Remove attendances linked to the calendar, this means that the workcenter is working 24/7
+        self.env['resource.calendar'].search([]).write({'attendance_ids': [(5, False, False)]})
+
+        dining_table = self.env.ref("mrp.product_product_computer_desk")
+
+        date_start = datetime.now() + timedelta(days=1)
+
+        production_table_form = Form(self.env['mrp.production'])
+        production_table_form.product_id = dining_table
+        production_table_form.bom_id = self.env.ref("mrp.mrp_bom_desk")
+        production_table_form.product_qty = 1.0
+        production_table_form.product_uom_id = dining_table.uom_id
+        production_table_form.date_start_wo = date_start
+        production_table = production_table_form.save()
+        production_table.action_confirm()
+
+        # Create work order
+        production_table.button_plan()
+        workorder = production_table.workorder_ids[0]
+
+        # Check that the workorder is planned now and that it lasts one hour
+        self.assertEqual(workorder.date_planned_start, date_start, msg="Workorder should be planned tomorrow.")
+        self.assertEqual(workorder.date_planned_finished, date_start + timedelta(hours=1), msg="Workorder should be done one hour later.")
diff --git a/addons/mrp/views/mrp_production_views.xml b/addons/mrp/views/mrp_production_views.xml
index 3c4ded7af34..bad8cf77f3a 100644
--- a/addons/mrp/views/mrp_production_views.xml
+++ b/addons/mrp/views/mrp_production_views.xml
@@ -105,6 +105,7 @@
                         <group>
                             <field name="date_planned_start"/>
                             <field name="date_planned_finished" invisible="1"/>
+                            <field name="date_start_wo" attrs="{'invisible': ['|', ('routing_id', '=', False), ('state', 'not in', ['draft', 'confirmed'])]}"/>
                             <label for="date_planned_start_wo" string="Scheduled Date" attrs="{'invisible': [('date_planned_start_wo', '=', False)]}"/>
                             <div class="o_row" attrs="{'invisible': [('date_planned_start_wo', '=', False)]}">
                                 <field name="date_planned_start_wo" attrs="{'readonly': [('move_raw_ids', '!=', [])]}"/>