$renderer['this.renderDate'] = "
renderDate : function(val, md, rec, row, col, s) {
    var date;
    date = Date.parseDate(val, 'Y-m-d H:i: s');
    return String.format('{0}', date.format(MODx.config.manager_date_format+' '+MODx.config.manager_time_format));
}
";

[
{"header": "Week", "width": "50", "sortable": "false", "dataIndex": "week"},
{"header": "Price", "width": "350", "sortable": "false", "dataIndex": "price"},
{"header": "Begins", "width": "150", "sortable": "false", "dataIndex": "begins", "renderer": "this.renderDate"},
{"header": "Ends", "width": "150", "sortable": "false", "dataIndex": "ends", "renderer": "this.renderDate"},
{"header": "Sold", "width": "50", "sortable": "false", "dataIndex": "sold"}
]