Im trying to add a coma to my form results but its just returning

'oak', 'wren'SELECT date FROM activities WHERE place IN (Array)Unknown column 'Array' in 'where clause'

PHP Code:
$out = array();
foreach(
$_POST['place'] as $place){
    
array_push($out"'$place'");
}
echo 
implode(', '$out); 

HTML Code:
$date = "SELECT date FROM activities WHERE place IN ($out)";
echo $date;
$grey = mysql_query($date)or die(mysql_error());