Creating a semi-static default date field (fixed month and day, year=NOW)

Question

I have a date field that needs an unusual default date: fixed day and month, but year=thisyear. That's outside the standard default date options.

I didn't want to write a custom module for one form field, so I tried this in template.php

function secta_form_alter(&$form, &$form_state, $form_id) {

  if($form_id == 'qic-node-form') {  // form to make a new QIC entry

  $QICdefault= date('Y')."-12-01";
  $form["field_qic_join"]["und"][0]['#default_value']['value'] = $QICdefault; // set the default  join date to YYYY-12-01

  }   // This is in template.php so will only show if form is displayed using the theme template 

}

But there is no sign of the form field default changing. :-( What am I missing?