Instructions

An irrigation system will also ensure your garden gets just the right amount of water. Not too little, not too much. Installing your own system isn’t much drama. All it takes is a basic understanding of the plants in your garden and a bit of planning.

Starting Off

Measure and draw your garden

Draw a plan of your garden to scale on graph paper. Include gardens, pathways, lawns, garden shed, pergolas, patios, driveways and any other structures you may have. Make sure you measure accurately as this will be how you work out the materials required.

Measure your water pressure

Next, you need to measure your water pressure. This will indicate your litres per minute (LPM), which dictates how many lines you need to run and how many watering methods you can plug in. To do this, grab your 9 litre bucket, put your tap on full flow and then time how long this takes to fill.

Time to fill = X
Litres per minute = 9 x 60
                                          X

Example: Time to fill = 12 (seconds)
Litres per minute = 9 x 60 = 540 ÷ 12 = 45 LPM
                                         12

Select the best type of watering method for each area

Match the different plant groups in your yard to different watering methods.

• Use drippers for shrubs and ground cover.
• Use micro sprays for flowerbeds, garden beds, shrubs and ground cover.
• Use drippers or misters for pots or hanging baskets.
• Use pop up sprinklers for lawns.

Mark on your plan where your watering methods will be used

Aim to have the least amount of nozzles possible. Use 90° in the corners. Use 180° along fence lines and buildings. Place 360° nozzles out in the open. It’s really important that you don’t mix different watering methods on the same lines. E.g. pop-ups should only been on a line with other pop-ups. This is because they have a different flow rate.

Space nozzles apart by the same distance as their spray radius. This ensures that the water spraying from one micro-spray should just reach the next micro-spray. The overlapping of spray patterns achieves the most even water coverage for your garden. The spacing between nozzles is not critical, plus or minus 20% is fine.

Calculate the number of lines

The average suburban home will on average have 4-8 watering lines.

• Count the number of each kind of pop-up, sprinkler, micro-spray or dripper.
• Write the total number of each in the number of nozzles column.

Multiply the number of each type of watering method by its litres per minute and write this in the litres per minute column.

Add the litres per minute for the watering methods and write it in the total litres per minute box at the bottom of each column.

For each watering method, divide the total litres per minute by your water supply capacity. Round this number up to the nearest whole number to work out the number of lines required.

Preparing the lines

Divide the nozzles for each watering method into groups. There should be the same number of groups as lines. The total litres per minute of each group of nozzles should be below that of the water supply. Mark the position of your system HUB. The HUB is the heart of each system where you control the operation of each line. It is normally located at a central garden tap. For each line select the most convenient route from the HUB to the area being watered. Mark these lines on your plan. You can have up to 4 lines coming off each HUB.

Installation

Attach watering line to the garden tap and roll out the pipe to straighten. Lay a brick on each end of the pipe. Use elbows on any corners. If it’s difficult to fit elbows, dip the fitting in hot water to soften them. Run water through the lines to remove debris before attaching nozzles.

For pop-ups

Dig up grass as tidy as possible where the lines are going to be run. This needs to be 100mm deep. Then lay the line. The simplest way to connect a pop-up sprinkler is to screw it directly into a male threaded tee or elbow. Always ensure that the top of the sprinkler is set slightly above ground level and not at the level of the grass, and use a 19mm pipe.

For micro-sprays

Micro-sprays screw into the top of rigid risers. This allows the pipe to be hidden under mulch and ensures the spray is above the height of plants. Use a stake to keep risers upright. A riser pipe stake will also secure the main pipe to the ground. A rigid riser stake is best when using 4mm tube to locate the spray away from the 13mm pipe.

Drippers

Drippers are also available with stakes attached for positioning in a pot or next to a plant.

Use the adjustable dripper if you believe plants or pots require different amounts of water. This is normally due to different pot sizes.

Use a pressure reducer for each dripper watering line.

Use a 4mm riser tube to run from 13mm pipe – it can be easily hidden to become unobtrusive.

Once all lines are run and attachments are fitted turn water on and check system to ensure all bits are spraying in the right direction.

And there you have it, a garden irrigation system that you put together yourself.