Configure different background on each virtual desktop:
1. Click on the desktop cashew located at the top right corner of the screen.
2. Click on ‘Zoom out’ in the drop down menu
3. Choose “Configure Plasma” from the toolbox that appears on the top right corner of the screen
4. In the screen that comes up check the “Use a separate dashboard” option.
5. Check the “Use Different activity for each desktop” option
6. Click on OK
7. Click on the magnifying glass at the bottom of the applets to zoom back into the desktop