mysql.sql

// mysql queries

INSERT INTO `tests` (`stamp`) VALUES ('2015-07-01T00:00:00+0000');
INSERT INTO `tests` (`stamp`) VALUES ('2015-07-01 00:00:00');
INSERT INTO `tests` (`stamp`) VALUES ('2015-07-01T00:00:00+0400');
INSERT INTO `tests` (`stamp`) VALUES ('2015-07-01 00:00:00');

php.php

<?php
        date_default_timezone_set('UTC');
        $table = TableRegistry::get('tests');
        $table->deleteAll(['id >' => '0']);

        $entity = $table->newEntity(
            [
                'stamp' => '2015-07-01T00:00:00+0000'
            ]
        );
        $table->save($entity);

        $entity = $table->newEntity(
            [
                'stamp' => new Time('2015-07-01T00:00:00+0000')
            ]
        );
        $table->save($entity);

        $entity = $table->newEntity(
            [
                'stamp' => '2015-07-01T00:00:00+0400'
            ]
        );
        $table->save($entity);

        $entity = $table->newEntity(
            [
                'stamp' => new Time('2015-07-01T00:00:00+0400')
            ]
        );
        $table->save($entity);

sql.sql

CREATE TABLE `tests` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `stamp` datetime DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

table_result

id	stamp
70	2015-07-01 00:00:00
71	2015-07-01 00:00:00
72	2015-07-01 00:00:00
73	2015-07-01 00:00:00