Frequently Asked Questions - about Canberra Irrigation
How much will maintaining/repairing my irrigation system cost?
It could be quick and inexpensive or it could be very expensive. It largely depends on how the system was installed.
Irrigation controllers, solenoid valves, wires, pipes etc generally last from 10 to 40 years or even more. For this reason many people don’t consider future repairs when installing an irrigation system. This is unfortunate as how an irrigation system is installed has a huge impact on how much it will cost to maintain and repair.
Accessibility is key. For example, replacing a solenoid valve that is easily accessible can be very quick (as little as 15 minutes and with a total cost perhaps $400). Replacing one that is buried deep underground, covered in roots, in an unknown location in the garden can take a day or more (costing many hundreds or even thousands of dollars). What can be a reasonably straight-forward and fairly cheap job, can become quite expensive if accessibility is poor.
The image on the left shows some old (grey) solenoid valves attached to a wall, one of which had failed and begun leaking. The easy accessibility of these valves made the repair quick, saving the customer money, compared to a system where valves are buried deep throughout the garden.
How best to install and irrigation system?
Again access is the main thing to keep in mind. Unfortunately I often come across overly complicated systems, often installed by non-irrigation system specialists, with a setup that is neither helpful to the operation of the system or the future cost of its maintenance.
On the right is an example of some solenoid valves that were completely entangled in tree roots. Replacing these valves was an expensive and painstaking process. The tree roots needed to be carefully removed, not only to enable access to the valves but also to prevent the risk of further damage to valves, pipes or wires.
The image below shows a new system that I installed. The valves are inside the green lidded box. The irrigation controller and water source are immediately above. This sort of simple system allows for inexpensive installation and straightforward maintenance of the fundamental components of your irrigation system.
How best to install and irrigation system?
Don't put valves or pipes near to plants that will grow much larger. This system you can see in the photo needed to be totally replaced due to a simple error placing the valves next to a tree and running the pipes inaccessibly under concrete.
What are the benefits of a modern internet connected smart controller?
Mains powered controllers and the valves they operate are durable and commonly last many years and even decades with little or no maintenance. You don't have to replace batteries and you can set them to automatically adjust amount of water applied to the month of the year. Newer internet connectable models can pause or reduce irrigation in response to weather. What it all means is once it's installed you can just forget about it and it will take care of itself.
You will need a power point to install the controller. Preferably an exterior power point which is not exposed to baking midday or afternoon sun in summer, which can damage controllers. How easy it is to run wires from controller to water source and connect water source by pipes to areas to be irrigated is a very important factor in the cost of installation.
Can I operate my watering system from my phone?
Smart controllers can be operated from your phone or computer while walking around your garden and from anywhere in the world using the mobile app or your internet browser.
Since smart controllers access weather data from the internet once you are happy with their setting for adjustments for season and weather then you shouldn't need to touch it further. Just set and forget.
What if connecting my controller to a power point is going to be too difficult and expensive?
Battery operated controllers are available such as the one in the photo. These controllers are very reliable but do need to have the batteries changed every 6 to 12 months. They often lack much of the functionality of the mains powered smart controllers such as internet connectivity. Most models need to be adjusted for season and if you want to reduce watering during rain events.
Garden beds - Should I use micro-sprays or drippers?
Bushes, flowers and trees are generally best watered using drippers/dripper pipe as this is more water efficient, more reliable, requires less maintenance and reduces weed germination. Drippers delivers the water directly to where it is needed and assists in deeper penetration of soil moisture. Micro-sprays spread water over plant leaves and soil surface which causes greater evaporative loses, which can be severe in the ACT"s dry climate . Drippers on the other hand apply water slowly from a single point source near each plant allowing water to permeate down deeper into the root zone. This also minimises moisture on the soil surface reducing the germination of weeds. Micro-sprays also regularly get clogged, broken and tangled requiring maintenance. Also, as plants grow they can block the spread of water by micro-sprays meaning the effect you initially got is not what you achieve down the road. Brown dripper pipe is now the standard in garden beds amongst professional irrigation installers and for good reason. As the rate of flow from dripper pipe is generally 2 LPH per dripper compared to 50+LPH from micro-sprays (though less numerous) you do need to run dripper pipe for much longer. See 'How much should I water?' Section below.
Vegetable gardens - Should I use micro-sprays or dripper pipe?
In vegetable gardens, dripper pipe is generally best for larger plants (e.g. tomatoes or zucchini) that can be planted immediately adjacent to each dripper,(every 30 cm). For smaller plants and plants you don't want to go to seed (e.g. lettuce, coriander etc) non-misting micro sprayers make it more certain all plants will get water right from planting. However, micro-spays can be considerably less efficient and encourage more weed growth, especially in narrow beds. Dripper pipe can still be a good option even for more difficult leafy green vegetables and is what I use in my vegetable garden with good results.
Lawn - Should I use sprinklers or subsurface dripper pipe?
Lawns need water over their entire surface area they are generally irrigated using pop up sprinklers. Closely spaced subsurface dripper pipe is another option. Subsurface dripper systems are more water efficient. On the other hand they are more expensive to install, can be damaged by shovels and garden forks (generally it's installed 10cm deep) and make initial lawn establishment more difficult. Most importantly it's much harder to tell if they are working. Probably a better way to increase water efficiency of lawn watering is to choose more drought tolerant grass species such as buffalo grass or native Australian grass species like Wallaby or Weeping Grass.
Subsurface irrigation was mandated by the ACT government during critical low water storage levels due to drought in the early 2000s. Water storage has been greatly increased since then to such an extent that water conservation measures wouldn't be needed again for decades. However, the record breaking drought which ended in the bushfires of 2019-2020 came close to requiring the reimposition of water conservation measures and highlights our uncertainty about what the future may hold in this regard. At this stage 2024 with the dams fairly full water conservation mandates, if they are required again, are at least some years of drought away.
What sort of dripper or sprinkler should I choose?
Drippers and sprinklers that apply water slowly are generally the best choice.
For dirppers I suggest fixed rate drippers, ideally 2LPH and not adjustable ones (as in photo). adjustable drippers are finiky and always having problems.
For sprinklers Hunter MP Rotator pop up sprinklers are great and the standard in Canberra.
When water is applied slowly it is more likely to penetrate and spread through the soil rather than run off. Another advantage is that the slower drippers or sprinklers emit water the more drippers and sprinklers you can run at one time off a single pipe.