Você pode editar o script de inicialização do cron ( /etc/init/cron.conf
) da seguinte forma:
# cron - regular background program processing daemon
#
# cron is a standard UNIX program that runs user-specified programs at
# periodic scheduled times
description "regular background program processing daemon"
start on runlevel [2345]
stop on runlevel [!2345]
expect fork
respawn
exec cron -L 7