run crond in the background

It’s quite easy. It’s also basically not findable on the web. Probably because a simple

# crond --help
crond: invalid option -- '-'
 crond [options]

 -h         print this message
 -i         deamon runs without inotify support
 -m <comm>  off, or specify prefered client for sending mails
 -n         run in foreground
 -p         permit any crontab
 -P         use PATH="/usr/bin:/bin"
 -c         enable clustering support
 -s         log into syslog instead of sending mails
 -x <flag>  print debug information

Debugging flags are: ext,sch,proc,pars,load,misc,test,bit

Provides the answer.