When to water: The 3, 2, 1 guide

Many people struggle to know how much to water their garden. How many days per week is right? And for how long? It can be confusing, but there is a handy tip to make it easier to know what to do.

A simple rule of thumb to use when scheduling your irrigation system zones is the 3, 2, 1 guide:

Water lawns three times a week.
Water your garden twice a week.
Water native plants just once a week.

This guide will encourage your plants to grow deep root systems, giving them better access to water and nutrients in the soil.

How long to water your garden

It’s best to give your plants and lawn 10 mm of water each time you irrigate and generally about 30 mm of water over a week.

As there are many different types of sprinklers that all apply water at different rates, there is an easy way to work out how long you should run your irrigation system or sprinklers for. It can also help to check how evenly water is being distributed.

All you need is a sprinkler catch can (available from most irrigation and hardware stores) or an empty tuna or cat food can. Then, follow the steps below:

Step 1

Place a few catch cans evenly across the irrigated area (in a grid like pattern) and run your irrigation for 10 minutes.

Step 2

Record the amount of water captured in each of your catch cans (tip: if using a tuna can, use a ruler placed into the centre of the can).  Add all the amounts together and then divide by the number of catch cans you are using to get an average amount of water per catch can. Write this figure down.

To find out how many minutes to run your irrigation, you just need to divide 100 by the figure you have written down. For example:

  • If you record an average of 10 mm of water in your catch can after watering for 10 minutes, divide 100 by 10 which will give you an irrigation run time of 10 minutes.
  • If you record an average of 5 mm of water in your catch can after watering for 10 minutes, divide 100 by 5 which will give you an irrigation run time of 20 minutes.

Step 3

Check if the water levels in all the catch cans are equal or near equal. This will tell you if your irrigation system is distributing water evenly. If it’s not, you may be able to adjust your sprinkler heads or nozzle size to distribute the water more evenly or change the placement of your sprinklers to ensure your lawn or garden is being watered evenly.

Common irrigation problems and how to fix them!

If you’ve noticed pools of water in your garden or dry patches of lawn, you may have a problem with your irrigation system. Here’s what you need to check:

Sprinklers

If your sprinkler is spouting water at odd angles or the area around it is soggy, chances are something is broken. To fix the issue, check the following:

  • Has dirt clogged your sprinkler head?
  • Are you using the correct water pressure required for your sprinkler? PGP or MP rotators require different pressures to operate.
  • Assess how many sprinklers you need and adjust the arc of your sprinkler to make sure all areas of your garden are reached.
  • Match your sprinkler heads to ensure an accurate and uniform distribution of water is achieved.

Pipes

Ageing pipes and splits in pipes are common irrigation issues. Here are some things you can do to fix or alleviate potential problems with your pipes.

  • Blockages are common, usually caused by ants or sediment built up in the pipes. Be sure to flush out your irrigation once every couple of weeks to keep pipes clear.
  • Are you using quality products? Keep in mind that poly or PVC pipes can last 30+ years.
  • Are you using the right pipe size? Generally pipes for residential homes need to be 25mm in diameter. In rural houses, water has further to go, so generally a larger pipe diameter is required.
  • Pipes with higher densities, thicker walls and high UV ratings tend to last longer - it’s worth making the investment.

Drippers

Drippers are by far the most efficient way to water your garden, but only when they work correctly. Be sure to keep an eye on them to check:

  • They haven’t popped off or exploded - this can happen if water pressure is too high.
  • The rubber hasn’t perished.
  • There are no blockages - flush your system every couple of weeks to prevent this from happening.
  • Flow regulating drippers will ensure the correct flow rate is being applied. Unregulated drippers can waste water and release in excess of 40 litres per hour.

Solenoids

If you see water trickling out of your sprinkler even though that station is off, chances are you have a blocked solenoid valve.

  • Check for debris or sediment stuck inside the valve - this is the most common issue.
  • If you see a pool of water around the valve, it could be broken. The pool of water could be due to a broken pipe, so be sure to check both before replacing any parts.

Irrigation timers and controllers

Whether it’s manual or fully automatic, every water wise garden needs an irrigation timer.

  • Ensure the timer is set correctly to avoid overwatering.
  • You may find that installing an automatic irrigation system will pay for itself in a relatively short period of time.

The benefits of smart irrigation systems

Smart controllers will automatically adjust your irrigation every day based on local weather conditions – reducing your water use by at least 20% and saving you money on your next bill.

A smart irrigation controller reads online weather data and responds via pre-set weather triggers. These triggers are set by you or a local irrigation expert via a web portal or app. Here are a couple of example triggers:

  • Turn off irrigation when it rains over 10mm.
  • Decrease irrigation by 50% when it rains over 5mm.
  • Increase irrigation if forecast temperature is over 35 degrees.
  • Stop watering if wind speeds are over 50km/hr.

Smart irrigation controllers can be accessed on your computer or via an app on your smart phone or tablet, allowing you to easily adjust your irrigation from anywhere in the world. Some smart irrigation controllers also include flow meters and other smart technology that will alert you of any leaks in your irrigation system.

To make your existing irrigation system ‘smart’, the first step is to determine what type of irrigation system you currently have. Generally, there are two types:

Standard (central automated) irrigation controllers

These timers are mains powered and can operate multiple irrigation lines. In most instances, mains powered standard irrigation controllers can be simply swapped over to a smart irrigation controller.

Programmable tap timers

These tap timers are battery powered and generally only operate one irrigation line. In order to upgrade from a programmable tap timer to a smart irrigation controller you will likely need extra work done including, installing an isolation valve, installing a back flow prevention device and installing solenoid valves for each watering station.

You will also need to ensure there is a strong consistent Wi-Fi signal at the location where you intend to install your smart irrigation controller and have access to an external power point.

Saving water on larger blocks

Having your irrigation set up effectively and keeping on top of any water leaks are the best ways to save water on larger blocks.

Irrigation schedules

Even if you have an automated irrigation system, it’s important to schedule your irrigation to water efficiently. Here are some guidelines to help:

  • Water after 8pm and before 6am to avoid evaporation during the heat of the day.
  • Follow the 3, 2, 1 guide to watering:
    • Water your lawns 3 times per week.
    • Water exotics like palms, twice a week or less.
    • Water your natives just once a week or less.
  • Adjust your irrigation schedule according to the seasons. If you live in the northern part of the Territory, follow the 3,2,1 guide above in the dry and once the wet season rains kick in turn your irrigation off and let nature do the watering!

Managing the pressure

Longer irrigation lines can often mean water pressure might drop as you get further away from the water source. This can mean that plants at the beginning of the line will receive excess water, while those further away may be under-watered. In turn, this might mean you water for longer to ensure these plants get a good drink.

Some tips to manage the pressure include:

  • Always try and loop your irrigation lines to keep pressure as even as possible along the line's entire length.
  • Use drippers rather than sprayers. These emit water really slowly meaning pressure drops will be less. They also put water right in your plants root zones.
  • Get pressure compensating drippers, sprayers and pop-ups – these better regulate the water flow helping ensure your coverage is even.

Leaks

On larger blocks leaks can be especially hard to find and you may not know you have a leak until it has already cost you a bucket load. Here are some easy tips to keep on top of leaks:

  1. Walk the lines. Once a month turn your irrigation on and then walk along all your pipes and lines checking for leaks. Often, you’ll find split joints and irrigation lines, leaky sprinkler heads or cracked pipes. You may also find sprinkler heads that are pointed in the wrong direction that can easily be re-directed.
  2. Keep an eye out for green patches. When you are not experiencing much rain, the only green patches you should see are the ones you water! If you see any random green patches this could mean you have a leak in an underground water pipe.
  3. Dripping taps and shower heads. Don’t leave them! Often, it’s just a matter of changing a washer or tightening a screw.
  4. If you know you have a leak but can’t find it there are plumbers around with specialised leak detection gear that allows them to track down leaks. They can even pin-point leaks through a concrete slab which makes repairing it much easier.

Selecting the right plants and soil

When planning your garden, it’s important to select plants that thrive in our extreme conditions.

Northern Territory gardens have traditionally consumed vast amounts of water to maintain exotic palms, shrubs, ground covers and lawns. However, there are ways to keep your garden looking great, while using less water:

  • Select water wise plants
  • Reduce lawn areas
  • Mulch garden beds
  • Adopt water wise watering practices

There are some great choices when it comes to choosing water wise plants:

  • Water wise natives
  • Water wise exotics

Plants and lawns that are planted into well prepared soil will be hardier and perform better than those in poor quality, compacted soil. Most soils in the Northern Territory are shallow and lack organic matter. There are ways to improve your soil:

  • Organic matter in the form of compost or aged animal manure can be dug into your soil to improve its nutrition and water holding capacity.
  • Dig gypsum and blood and bone into your soil to prepare it for your new garden.