diff --git a/platform/forms/res/templates/controls/datetime.html b/platform/forms/res/templates/controls/datetime.html
index e2accf7c8f..6dae89eb8a 100644
--- a/platform/forms/res/templates/controls/datetime.html
+++ b/platform/forms/res/templates/controls/datetime.html
@@ -38,7 +38,7 @@
                        placeholder="YYYY-DDD"
                        ng-pattern="/\d\d\d\d-\d\d\d/"
                        ng-model='datetime.date'
-                       ng-required='true'/>
+                       ng-required='ngRequired || partiallyComplete'/>
             </span>
             <span class='field control time sm'>
                 <input type='text'
@@ -49,7 +49,7 @@
                        integer
                        ng-pattern='/\d+/'
                        ng-model="datetime.hour"
-                       ng-required='true'/>
+                       ng-required='ngRequired || partiallyComplete'/>
             </span>
             <span class='field control time sm'>
                 <input type='text'
@@ -60,7 +60,7 @@
                        integer
                        ng-pattern='/\d+/'
                        ng-model="datetime.min"
-                       ng-required='true'/>
+                       ng-required='ngRequired || partiallyComplete'/>
             </span>
             <span class='field control time sm'>
                 <input type='text'
@@ -71,7 +71,7 @@
                        integer
                        ng-pattern='/\d+/'
                        ng-model="datetime.sec"
-                       ng-required='true'/>
+                       ng-required='ngRequired || partiallyComplete'/>
             </span>
             <span class='field control timezone'>
                 UTC
diff --git a/platform/forms/src/controllers/DateTimeController.js b/platform/forms/src/controllers/DateTimeController.js
index bf122c3f9c..530c966380 100644
--- a/platform/forms/src/controllers/DateTimeController.js
+++ b/platform/forms/src/controllers/DateTimeController.js
@@ -52,6 +52,20 @@ define(
                 if (fullDateTime.isValid()) {
                     $scope.ngModel[$scope.field] = fullDateTime.valueOf();
                 }
+
+                // If anything is complete, say so in scope; there are
+                // ng-required usages that will update off of this (to
+                // allow datetime to be optional while still permitting
+                // incomplete input)
+                $scope.partiallyComplete =
+                    Object.keys($scope.datetime).some(function (key) {
+                        return $scope.datetime[key];
+                    });
+
+                // Treat empty input as an undefined value
+                if (!$scope.partiallyComplete) {
+                    $scope.ngModel[$scope.field] = undefined;
+                }
             }
 
             // Update value whenever any field changes.