||06-23-2012 06:25 AM
Adding a sprinkler head should not be a problem but to be sure you should total the draw on the circuit in gallons per minute flow rate and water pressure being demanded. You should also make sure you have adequate water pressure. The heads should have information about flow and pressure demands on their packaging. For a crude calculation you can just add up data for all the heads.
Another thing to think about? Convert you flower beds to drip irrigation. It is good for the environment and great for plants. Drip waters in gallons per HOUR and not gallons per MINUTE and puts water only where you want it. There are seldom issues with running out of pressure or water flow in residential drip irrigation applications.