Rails cron with whenever, setting the environment

Whenever doesn't detect your environment, it just defaults to using production. You can set the environment for all jobs using set:

set :environment, 'staging' 

Or per job:

every 2.hours do 
  runner 'My.runner', :environment => 'staging' 
end 

Don't write the RAILS_ENV variable. It should set it automatically.

every 1.day, :at => '4am' do
  command "cd #{RAILS_ROOT} && rake thinking_sphinx:stop"
  command "cd #{RAILS_ROOT} && rake thinking_sphinx:index"
  command "cd #{RAILS_ROOT} && rake thinking_sphinx:start"
end

It works in my app:

every 4.days do
  runner "AnotherModel.prune_old_records"
end

$ whenever --set environment=production
0 0 1,5,9,13,17,21,25,29 * * /Users/weppos/Sites/git/app/script/runner -e production "AnotherModel.prune_old_records"

$ whenever --set environment=development
0 0 1,5,9,13,17,21,25,29 * * /Users/weppos/Sites/git/app/script/runner -e development "AnotherModel.prune_old_records"