Subsoil Irrigation for Lawn

Criksys · Jan 16, 2017 11:44 pm

Hi guys....... I am currently building in North Queensland and will be taking on the landscaping myself....... Its a simple task, turf and some garden beds here and there.

I would like to install a subsoil irrigation system just for the front lawn area so its always green and will add to the street appeal of my house. The area is approx 6m x 12 m so total 72m.......

What sort of systems are there these days? Is everything sold at bunnings and if so is there a good guide online? I have some experience with basic irrigation systems but by no means am an expert.

Thanks in advace for your assistance

Philip_J · Jan 17, 2017 5:36 am

Hi, not speaking from personal experience, but more the hours of time spent researching in this forum, but Fu Manchu reccomend against them.

I remember reading that with you can great water efficiency and better watering from something like the Hunter MP rotars set up as your standard pop up irrigation system.

He also mentioned that unless you're getting professional grade materials and installation then it can lead to trouble later own with pipes getting blocked or damaged underground etc.

In saying that, I believe I came across some Toro underground pipes that had some sort of deterrent or herbicide to avoid roots getting in the holes.

Other considerations are the initial watering requirements as new lawn or turf will still require some above ground water initially

Just my 2 cents. Good luck with it all.

Phil

shamuscassar.sc · Jan 17, 2017 6:28 am

I invested a lot of money in subsurface irrigation for the lawn at my prior house. The system ended up getting leaks etc to the point where I stopped using it and the only solution would be to rip all the lawn up and start again.

I would strongly recommend against it. I have now starting using pop up sprinklers again.

Another point. With subsurface irrigation you also need to invest in a backwash prevention system and regular inspections because the piping has an built poison to prevent weeds from penetration the tubing.

Criksys · Jan 17, 2017 3:59 pm

My main reason for wanting sub soil irrigation for the front lawn alone is sprinklers are banned with our current water levels and the Council have not been able to source a viable way to get us off water restrictions....... we cant even use stand sprinkers on the end of the hose. We have to only use a nozzle and hose the lawn only 3 days a week. Im a shift worker and i wont able to water every chance im aloud to

Criksys · Jan 17, 2017 4:08 pm

I want something hidden (as there are council water patrols and big fines for those that break their rules) and i like the idea of subsoil being more water efficient. I dont mind regular maintenance as 'every mans home is their castle right'

shamuscassar.sc · Jan 18, 2017 7:02 am

All irrigation requires maintenance but subsurface irrigation is another level, to the point where it can't be repaired without virtually destroying your lawn.

Turtle1 · Jan 27, 2017 9:24 am

yep go for subsoil irrigation at least now you know the issues with it.

Criksys · Jan 27, 2017 6:17 pm

Any advice or products you would recommend turtle1? I am only going to use it for the front lawn and council strip, so provided it is a qaulity product and a careful installation, i dont see any real cons to using it. It is currently and will always be illegal to use pop up sprinkler systems in townsville, due to the councils inability to find a renewable water source, so i am definately going subsoil......... just want some advice on products and installation tips please

SaveH2O · Jan 27, 2017 9:17 pm

About 6-7 years ago, I saw a mention in an Alternative Technology Association thread about a sub surface watering system called KISSS. I read up on it and even spoke to a happy landscaper who had installed it but never had experience of it myself.

Anyway, I just Googled it and it still exists!

http://www.kisss.com.au/Home.aspx

Obviously the inventors hadn't considered the product's wider usage potential when they appeared on the New Inventors...as often happens.

http://www.abc.net.au/tv/newinventors/txt/s2152437.htm

Criksys · Jan 28, 2017 4:37 pm

Thanks heaps SaveH2O....... ill contact them and check it out....... any other products boys and girls? I have probably all of February to research until ill have to start buying and installing in March or early April

TheGardenWhisperer · Mar 09, 2017 1:54 am

In WA this type of system is a big no no under lawns.
Make sure you have an RPZ valve installed as part of the system and get it maintained and certified each year by a plumber.
Fertiliser applications will need to go through the system or have thorough watering after.

The best water management experts here now suggest that MP rotators are a safer and efficient option.

SaveH2O · Mar 10, 2017 5:14 pm

Hi Fu and welcome back.

I take it that the reason it is a big no no in WA is because of the sandy soil...which is logical. Did some people actually install it on sandy soil over there and is there any other reason for the no no?

TheGardenWhisperer · Mar 23, 2017 11:53 pm

The reason is actually nothing to do with sandy soil.
It is to do with the laws around installing "subsurface" drip line.

Irrigation Australia Regulations State:

"Many of these systems are commonly referred to as SUB-SURFACE irrigation. Reference is made herein to SUB-SURFACE and to SUB-MULCH irrigation. The distinction made between the two is that SUB-SURFACE irrigation involves the installation of drip-line BELOW ground level (e.g. under turf). SUB-MULCH irrigation, as the name suggests, involves the installation of drip-line ABOVE ground but covered in a layer of mulch.
Drip-line buried below ground has a greater likelihood that roots may grow into drippers and clog them than does such tube placed above-ground and mulched. Manufacturers of drip-line therefore recommend that any truly ‘SUB- SURFACE’ system be fitted with the means to dose a root-intrusion inhibiting chemical (such as TreflanTM) into the system to prevent such from occurring. Where ANY chemical is dosed into a system connected to the mains water supply an RPZ Backflow Prevention device has to be installed at this point of connection.
The cost of such a device usually precludes the installation of such a system, due to its cost, and therefore the installation of SUB-MULCH DRIP IRRIGATION in garden beds is recommended. Sub-surface irrigation system layouts are covered in the section on SUB-SURFACE IRRIGATION IN TURF. If required, the same system layout can be used in garden beds (with the appropriate means to prevent root-intrusion and with the appropriate backflow prevention)."

To be clear, an RPZ Valve is not the same as a regular back flow valve.
By law it must be maintained annually by a licenced plumber who certifies it is functioning as it should.

They will add around ~$600-$1000 to the cost of such a system.

Now moving to the herbicide used.
Trifluralin is transmitted into the water via a filtre (coloured brown) that has a series of plastic discs inside impregnated with the herbicide.
Trifluralin is banned in the European Union.
More about Trifluralin: http://www.pesticideinfo.org/Detail_Che ... Id=PC35146

Without an RPZ valve this herbicide will find it's way into the mains water of the home. Meaning it will be consumed in the tap water.
Also, it can make its way to other homes and compromise the integrity of the scheme water.

This further leads me to explain why there are other reasons we now look to MP rotators in lawn applications.

Fertiliser application will need to be done via the system also.
Many people have applied standard lawn fertilisers to subsurface irrigated turf and killed off the lawn because there is no irrigation to dissolve the fertiliser through to the roots.

Having liquid fertilisers applied is one of the most inefficient types of fertilisers we know of leaving plants less than an hour to obtain the nutrient. This contributes to nutrient leaching.

The scheme water supplying the home must be protected by an RPZ valve to prevent fertilisers making their way through the system into the homes water supply.

Then we move to the ridiculous use of fungicides and pesticides on turf without proper lab tests to determine the treatments needed. (if at all)
Once again the RPZ prevents pesticide and fungicide residue compromising a homes water supply or worse still, the supply of other homes.

SaveH2O · Mar 24, 2017 9:16 am

Hi Fu,

Thanks for your usual highly informative reply.

Reduced pressure zone devices (RPZD) are expensive and are about $250 for a 20mm one...plus fitting of course.

I am unaware of "Irrigation Australia", I will look them up when I have time but the applicable regulations will not be theirs, they will refer to AS/NZS 3500.1 Section 4 CROSS-CONNECTION CONTROL AND BACKFLOW PREVENTION.

I am going to inquire about the "below ground" drip lines sold in the big green shed and other outlets and see whether they reference herbicides and Trifluralin in particular. If it is in their data sheets, then it should be legislated to make it compulsory to also clearly state this on the product's description at the point of sale.

One of our websites references drip hoses and that website will soon have information updates. If there is anything of public interest that needs to be made known about sub surface irrigation, then that information will also be included in the updates.

TheGardenWhisperer · Mar 24, 2017 2:37 pm

Irrigation Australia is the umbrella organisation for all irrigators in Australia.
They are the authority in for the standards in Australia.
They work closely with state water depts, water policy development, small business contractors, and handle industry training and qualifications.

https://www.irrigationaustralia.com.au

SaveH2O · Mar 25, 2017 9:06 am

The Garden Whisperer

Irrigation Australia is the umbrella organisation for all irrigators in Australia.

They are the authority in for the standards in Australia.

Not sure what you mean here. Australian Standards are produced by Standards Australia, a private company. Australian Standards have no legal standing unless they are either referenced in a contract, are referenced in the National Construction Code (NCC) or are legislated.

TheGardenWhisperer · Mar 25, 2017 10:30 am

They will consult industry groups in developing Australian Standards.
To give a recent example, Dr. Josh Byrne, when designing and building his 10star home was surprised to find there were no Australian Standards in place for various sustainable plumbing aspects of the home.
He was able to work with a number of authorities to create industry guidelines and Australian Standards for them.

It is important Standards Australia remains independent, however they don't know everything so engage the industries involved to create them. Or alternatively, collaborative submissions from industry or individuals are put forward to them.

TheGardenWhisperer · Mar 25, 2017 10:39 am

I also mean that industry organisations/associations are important to make sure best practices/industry guidelines are used.
Eg. Master Plumbers Association, Master Builders Association, Institute of Australian Consulting Aboriculturists.

I refer to the term "standards" in the sense of a standard of work and that standard of work following Gov. guidelines

TheGardenWhisperer · Mar 25, 2017 10:49 am

Summary:
Try not to use drip line under turf.
If done, use appropriate means to stop what we put onto lawns from getting into our water we drink.
Regular back flow valves will not protect drinking water from fungicides, pesticides, fertilisers and the herbicide required to prevent root intrusion.

Just use MP rotators. Easy.

Criksys · Apr 08, 2017 3:37 pm

Ok guys sorry for the absense and thanks everyone for the input, i really appreciate your time and input. I have been persuaded to not go with subsoil and instead ill use pop up sprinklers....... my next query is what is the best brands/ systems to use and please bear in mind i have a limited budget

Is there a topic on this site already with the info? If someone could send a link that would be great