DIY garden sprinkler systems

November 18 2015

Install your own Automated Garden Sprinkler System

A garden sprinkler system means you can have lush lawns and garden all year round with no unsightly garden hoses to spoil the view or create obstacles for dogs and children.

To start, draw a scale diagram of your yard, including the lawn and any other garden area you want your garden sprinkler system to water.  This will help you plan where to lay your pipes and calculate the number of sprinkler heads you need, lengths of pipe and other irrigation fittings you’ll need.

Next identify the type of planting in each zone – lawn, flower garden, shrubbery, trees, vegetables etc. Different areas of the garden will benefit from different sprinkler heads.  Pop-up or gear driven heads are best for lawn areas; for shrubs and flowers use shrub heads or bubblers; fixed pop-up heads should be installed in zones adjacent to decking, driveways, paved areas or buildings that don’t need to be watered.

Work out the type of head you need for each zone, and then the size of head that will give you the most efficient spray. You want your sprinklers to overlap slightly to ensure good coverage. Too much overlap can cause waterlogging. You also want to avoid too much spray over non-garden areas (such as driveways and paths), otherwise you’ll be spending unnecessary money on your water bills.

On your diagram, identify the best location for each sprinkler head based on the diameter of the spray. Mark the position of the sprinkler as well as the circular area of the spray distance. Now you should get a good idea of how efficient your sprinkler irrigation system is going to be. An easy way to tweak your design is to cut out circles to scale and move them around your plan. Mark each type of sprinkler head with a different colour to avoid confusion. Once you’ve settled on the most effective arrangement, trace your circles onto your diagram.

Sprinklers have a rating based on their flow rate, so to work out how many sprinkler heads you can accommodate from a single main line, you need to test your flow rate.  The easiest way to do this is to how long it takes to fill 10 litre bucket with the tap fully open, and no other taps on. Divide the number of litres (10) by the time it takes to fill the bucket and multiply by 60. For example, if it takes 30 seconds to fill your bucket, the calculation will be:

(10 ÷ 12) x 60 = 50 lpm (litres per minute)

Start your main line from the garden tap where you will install your control valves, tap timer and backflow preventer.  It is important to install a backflow preventer because without one, if the water system loses pressure you can risk syphoning water from the sprinkler system into the potable water, causing a potential contamination.

You don’t necessarily need to automate your garden irrigation system but it is a convenient way to manage your garden watering. It means you can set and forget whether you’re at home, on holiday or at work. It is a more efficient way of controlling your water usage and costs. It’s also a good idea to install a moisture sensor or rain detector with your automated watering system. This will prevent your system operating after a good rain, saving you more money.

Branch lines lead off the main line to each sprinkler head. A 20mm pipe can usually accommodate two sprinkler heads, but ideally you should have one sprinkler per branch line.

Once you’ve drawn your design for your main and branch lines, you can calculate the materials you’ll need to install your garden irrigation.

Mark out your irrigation design on your lawn and garden using markers (such as garden stakes) for each sprinkler head and joiner, run garden twine or rope to mark out where your pipes will go. Dig you ditches 15 – 30cm deep.

Lay out your pipe and joiners and position the sprinkler heads ready to connect.

Start your installation from the tap.

Before you attach your sprinklers, turn on the water to flush the pipes of any debris which may be inside. This only takes a few minutes and is important prevent clogging your sprinkler heads later on.

Now attach your sprinkler heads. To support the heads in an upright position, compact your soil around the heads. Make sure your sprinkler heads are buried slightly below your preferred lawn height to avoid damage when mowing.

The moment of truth! Test your system by turning on the water and observing the spray coverage of each head. Some heads allow you to adjust the rotation or direction of the spray, you can also control the diameter of water spray by manually adjusting the water pressure.

Check your pipes for leakage by walking along each pipe will the water is flowing. Leaks are easy to spot and need to be corrected before you backfill your trenches. Once you’re happy your irrigation system is in place and working effectively, pack your soil firmly over your pipes.

Walk the length of your ditches to check for water leaks, and when you are satisfied there are none, turn the valve off and backfill your ditches, packing the soil in firmly.

Remember to protect all your exposed piping, valves, and other equipment from the rain and hot weather.  Strong sunlight can accelerate deterioration of some plastics and other materials.

Whenever you need advice or a chin wag about your garden irrigation project, come in a chat to one of Irrigation Supplies specialists. We’re open 7 days and happy to offer advice on design and materials. All too complicated? Talk to us about our irrigation design service.