Including custom fields in search?

I use custom fields for lots of my content on both Posts and Pages, so that half of the text will be in the main post body and the other half in a custom field.

Unfortunately, when doing this only the text in the post body is searchable.

I want to have all the custom fields included in the search (just joined together as one). Preferably without installing a plugin, as all the plugins I have seen do not seem to be able to do this or they add loads of options I don’t need.

I just would like one search box, that uses WordPress’s default search but finds words in custom fields as well as those in the main body.

Is this possible?

You could use a plugin like “Search Everything” which lets you toggle what to include in the search (including Custom Fields). Check it out here: http://wordpress.org/extend/plugins/search-everything/