I'm using ZSH and wanted to open crontab via subl as well. Here is how for that setup:
In your ~/.zshrc export:
export VISUAL="subl -w"
export EDITOR="$VISUAL"
(Thanks to all answers for the -w wait flag)
Open a new shell or source again via source ~/.zshrc
Then run crontab -e
In your crontab file, make sure to add SHELL=/usr/bin/zsh at the top if you want to use ZSH in your cron script.
Add your crontab at the end of the file.
Make sure you have a new line at the very and of the file.
Save in sublime and close the tab/window.
Check your shell again:
crontab -e
no crontab for <user> - using an empty one
crontab: installing new crontab
new crontab file is missing newline before EOF, can't install.
Do you want to retry the same edit? (y/n) Y
crontab: installing new crontab