I'm not sure if it's going to work but try this...
$stream = ftp_connect( 'host', 21 );
ftp_login( $stream, 'user', 'pass' );
if( ftp_put( $stream, $destination_file, $source_file, FTP_ASCII ) )
echo 'Upload successful.';
else
echo 'Upload failed.';
ftp_close( $stream );