Automatic sprinkler systems are a great option for managing the irrigation of your lawn and plants. Not only do they save you the time and effort of undertaking the task manually, but they can also conserve a great deal of water. You'll need to plan this project carefully, and you may need professional assistance to do the job right.
Planning
The first part of the planning process will be to divide your yard into zones. You'll need to consider things like soil type, types of plants, and sunlight levels to figure out how much water each zone will need. You'll be able to program each zone to administer different amounts of water on different schedules, but you won't be able to change the flow of water within a particular zone.
The water supply to your system will need to maintain a very specific water pressure in order for the system to run properly. And, all of this will have to be able to be supported by your water service. Consulting an irrigation contractor or other professional would be very beneficial in sorting this out. Also, the system you purchase should come with specific instructions. Follow these carefully. You may need to contact your local water service and talk to them about installing a supply line.
Installation
Lay out the entire system before you do any digging. This will help you figure out if you've laid everything out correctly and not overlooked any obstructions like trees, fences, etc. If you find you need additional parts, stick with the manufacturer of the rest of your system; different companies' parts may not be compatible.
The system controller should be mounted inside in an easily accessible location at about eye level (inside a garage or shed are ideal spots). Connect this to the valve box, which should be underlain with gravel to prevent dirt from getting into the valves. Then, connect the main lines for each zone to the proper valve.
Next, you can dig trenches for the water lines, laying the lines into the trenches and installing sprinkler fittings as you go. You may also consider installing traps and waste vents to drain the system. This will be necessary in areas that experience cold winters; you'll want all water to drain out of the system in the fall so it doesn't freeze in the winter.
Once all the water lines are in place, you can install the sprinkler heads as well as filter screens. Go one zone at a time, checking the pressure as you do. It's important to install pressure regulators in each zone, so that you can adjust the water pressure. If the sprinkler heads pop up too slowly, you'll need to increase the water pressure. Decrease it if the water mists.
After you've completed installation, test the system. Make any adjustments necessary and then fill in the trenches. These should be lined with sand, gravel, or something similar before being covered with dirt. Monitor the system and your yard over the next few weeks, making adjustments to your system's program as necessary.