Problem with sorting dates with jquery tablesorter

Try adding a Tablesorter parser to your date column. Tablesorter comes with a parser for shortDate, usLongDate and isoDate.

$("#table").tablesorter({
    headers: { colNum: { sorter: 'shortDate'} }
});

where colNum is the column with the dates. The only example I could find on the tablesorter site is here. This also works if tablesorter is sorting numbers wrong as well. There are other parsers as well for percent, ip address and more. Take a look near the end of the source code and they'll be listed there.

Edit: In looking at the source code, the dateFormat option appears to be looking only for "us", "uk", "dd/mm/yy" or "dd-mm-yy". What happens when you try "uk"?

I got the same problem, and I added a custom parser called datetime:

$.tablesorter.addParser({
    id: "datetime",
    is: function(s) {
        return false; 
    },
    format: function(s,table) {
        s = s.replace(/\-/g,"/");
        s = s.replace(/(\d{1,2})[\/\-](\d{1,2})[\/\-](\d{4})/, "$3/$2/$1");
        return $.tablesorter.formatFloat(new Date(s).getTime());
    },
    type: "numeric"
});

Then you just need to apply that format to the columns you want, as Gabe G exposed (For example to assign this sorter to the first column you should do the following:

$("#mytable").tablesorter( 
    {   dateFormat: 'dd/mm/yyyy', 
        headers: 
            {
                0:{sorter:'datetime'}
            } 
    } ); 

You can also add a hidden span tag before your date in numerical format (yyyymmdd). This text will come first and be used for sorting but it will be hidden from sight and only show the format you want.

    <td><span style="display:none">20130923</span>23 September 2013</td>