Instead of `get_option`, use [`home_url`][1] which will determine ...

> the appropriate protocol, "https" if `is_ssl()` and "http" otherwise. If
> the `$scheme` argument is "http" or "https" the `is_ssl()` check is
> overridden. 
> 

In fact, [`network_home_url`][2] would be more appropriate since you are talking about Multisite.

Those [should return the same value][3] that you are trying the access in your code-- the `home` option key-- but with the appropriate protocol.


  [1]: http://codex.wordpress.org/Function_Reference/home_url
  [2]: http://codex.wordpress.org/Function_Reference/network_home_url
  [3]: http://core.trac.wordpress.org/browser/tags/3.5.2/wp-includes/link-template.php#L1906