Folder actions on OS X observing all subfolders

I have a folder that I would like to add a folder action to. The action works great when the file is added to the top level. But when a file is added to and sub-folders, the action is not enabled. Is there a way to ensure that a folder action is enabled when a file is added to any of its subfolders?

launchd has a feature called watchpaths which can run a .sh script or whatever you please when changes occur.

depending on the security requirements of paths are you are looking to monitor and when you'd like it monitored (when logged in or always?); determines where you place the plist.

 ~/Library/LaunchAgents         Per-user agents provided by the user.
 /Library/LaunchAgents          Per-user agents provided by the administrator.
 /Library/LaunchDaemons         System-wide daemons provided by the administrator.
 /System/Library/LaunchAgents   Per-user agents provided by Mac OS X.
 /System/Library/LaunchDaemons  System-wide daemons provided by Mac OS X.

Example: ~/Library/LaunchAgents/com.tellemewhen.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
    <dict>
        <key>Label</key>
    <string>com.tellemewhen.plist</string>
    <key>OnDemand</key>
    <true/>
    <key>Program</key>
    <string>/PATH/TO/YOURSCIPTTORUN.sh</string>
    <key>ProgramArguments</key>
    <array>
            <string></string>
    </array>
    <key>WatchPaths</key>
    <array>
            <string>/path/to/watch</string>
    </array>
    </dict>
</plist>

launchctl load ~/Library/LaunchAgents/com.tellemewhen.plist loads the plist.