diff --git a/mod/data/field/textarea/field.class.php b/mod/data/field/textarea/field.class.php
index 69fd9dbe4ec..6dd703f3e04 100644
--- a/mod/data/field/textarea/field.class.php
+++ b/mod/data/field/textarea/field.class.php
@@ -153,7 +153,8 @@ class data_field_textarea extends data_field_base {
         $editor->use_editor($field, $options, $fpoptions);
         $str .= '<input type="hidden" name="'.$field.'_itemid" value="'.s($draftitemid).'" />';
         $str .= '<div class="mod-data-input">';
-        $str .= '<div><textarea id="'.$field.'" name="'.$field.'" rows="'.$this->field->param3.'" cols="'.$this->field->param2.'" spellcheck="true">'.s($text).'</textarea></div>';
+        $str .= '<div><textarea id="'.$field.'" name="'.$field.'" rows="'.$this->field->param3.'" class="form-control" ' .
+            'cols="'.$this->field->param2.'" spellcheck="true">'.s($text).'</textarea></div>';
         $str .= '<div><label class="accesshide" for="' . $field . '_content1">' . get_string('format') . '</label>';
         $str .= '<select id="' . $field . '_content1" name="'.$field.'_content1">';
         foreach ($formats as $key=>$desc) {