Why and how to install garden irrigation

<p><em>From GARDENA Brand Ambassador Sarah the Gardener</em></p><p>Keeping a garden, no matter how small, well-watered can take a lot of time, with a hose or lugging watering cans.</p><p>Irrigation can free up valuable time and ensure your plants receive exactly the water then need at the best time of day - early in the morning before the heat of the day drives up the evaporation rates.</p>

Setting up irrigation can be a daunting task as there are an array of components available to suit a wide range of different gardening needs. It does require a little bit of planning, and some set up time, but after that you will have trouble free, efficient watering and your plants will thank you.

Make a plan

First measure your garden and create a map of your garden to scale as accurately as you can.

The bucket test

  • Find out your flow rate by doing the bucket test.
  • Turn on the tap you will be using for your irrigation and time how long it takes to fill a 9 litre bucket.
  • The water flow rate helps you to decide which components to use and how many of them without losing water pressure and functionality.
  • Using the Neta chart below, work out your flow rate:


  • Once you have this magic number, you can begin to work out what you need for your garden.

Consider the needs of your plants

Look at what you have growing and think about their watering needs. For example:

  • Lavender needs less water than hostas.
  • Most vegetable plants don’t like overhead watering.
  • Containers and hanging baskets are always thirsty.

On your map outline where plants with different needs are in your garden. Create different zones so you can treat their watering needs differently.

Drippers or Sprayers?

Decide, based on the type of plants, how you want to deliver their water.

Drippers slowly water the soil and roots directly with less evaporation and dry plants reducing the risk of fungal disease. Great for pots, hanging baskets, vegetable crops and specific plants that need individual attention.

Sprayers and sprinklers suit to large areas like lawns or large garden beds. Waters everything in its range including the soil and entire plants.

Most sprayers have a full, half or quarter circle or even in a narrow strip spray pattern options so paths, walls and fences stay dry, and water isn’t wasted. You can also choose what kind of spray – from a fine mist to larger droplets. There are pop up sprinklers for the lawn, so they don’t get in the way of the lawn mower.


Designing your irrigation system

This stage can be a little fiddly, but also very satisfying.

  • Decide which sprayers or drippers you want to use and find its flow rate.
  • Dividing your flow rate from the bucket test by the sprinkler flow rate to find out how many you can have in a line.
  • A line is the 13mm irrigation pipe you will need that runs from the tap to the zone. You can have more than one line if you have different zones or large areas.
  • Make sure all of the sprinklers in the line have the same flow rate.
  • Avoid mixing drippers and sprinklers in the same line.
  • Plot them on your plan by drawing a circle to represent the sprinklers coverage zone. For good coverage, each zone should reach across to the centre of its nearest neighbour.
  • Your plan should end up with a range of overlapping circles that cover the entire garden.
  • You may need to choose a different kind of sprinkler if you can’t get full coverage and still stay within your flow rate. There are plenty to choose from and something should work out for you.

This can take a fair bit of time to get right, but it is worth the effort now to get a good working system.

Linking it all together

Plan how the 13mm pipeline will go from the tap to the irrigation zones. Keep it as out of the way as possible to avoid a tripping hazard.

Drippers and sprinklers can be attached directly into the main line or can branch off into the middle of the garden with a 4mm tube that connects into the dripper.

What else you will need:

  • Barb elbow – takes pipework around corners.
  • Barb tee - creates a branch to your zone.
  • Rigid pipe stakes - hold the pipe in place.
  • Barb ends - stop the water at the end of the line.
  • Rachet clips – locks connectors in place – don’t skimp on these.
  • In line valves – turns a section of your zone on or off.
  • Stake – some sprinklers need extra support.
  • Multitool – to punch holes and attach connectors.
  • Goof plug - to repair holes.

Putting it all together

Once you have all of the components, attach everything together exactly as it is in your plan. Everything should click together easily.

TIP: If the pipe is curled from the packaging, lie in the sun to unwind.

TIP: Soaking pipe ends and connectors in hot water softens them and makes joining them together so much easier.

  • Once the sprinklers have been attached to the line zones, gather all of your line pipes back at the tap.
  • Consider using a tap splitter so you can still use your tap freely without unhooking your irrigation.
  • If you have multiple lines then a Gardena Water Distributor Automatic and compatible water controller is ideal as it can water six zones at a time, programmed to the individual needs of the zone.


How to water

A water timer or computer is invaluable for ensuring the garden is watered at the right time for the right length of time.

The length of time to water depends on your conditions. A good place to start is for 20 minutes every other day and then adjust if your soil is getting too much or not enough water. Dig down halfway out from your sprinkler reach to see how far the water is penetrating the soil.

It does take a lot of effort, wrapping your head around designing the right system for your garden, and a lot of scrabbling around in the dirt to lay it all out and get it installed. However, once it is done, you can sit back and enjoy your garden without having to stand there for hours with a hose.

For more detailed information on component specifications check out https://www.netagarden.co.nz/ or pick up a Neta brochure at your local Mitre 10.