How to plan drip irrigation - Layout & zones?

[tanveersattar]

Hello All, 

I need help to plan drip irrigation in my backyard. I have planting beds along three sides of the backyard, with a mix of fruit trees, lilly pillies, small veggie beds some flowers/shrubs. Also on the side of the house there is also a planting area with daisies and other smalls flowering shrubs as shown in the image below.

The bed on the south side has three fruit trees and three small round veggie patches and it is 7 meters long.

The bed on the west side has 8 lilly pillies and some flowers (daisies and abela) under-planted. It is 14 meters long. 

The bed on the north side has some citrus plants and an orange jasmine at the end. It is 10 meters long. 

The area, next to the house, on eastern side has some daisies and other small shrubs/grasses. It is 14 meters long. 

A recycled water tap is also on this eastern wall (as shown below). 

I may also need to run two lines to the side areas of the house where we have some photinias in the large pots. If i extend irrigation to the north side and south sides of the house this will add another 10 meter on each side.  

So total length of polytube in the backyard is 45 meters. And if i add two side paths it will be 20 meters more. 

My questions are below:

Q1: If I have to run the main line from tap to cover all these areas around, should I use 19mm or 25 mm polytube?

Q2: As the plants water requirements are different (trees may need water less frequently than the veggies or shrubs/flowers) should I run two separate main lines of 19mm OR 25mm so that I can set frequency separately? OR there should be another way to meet different water requirements? 

Q3: If two main lines are to be used, does that mean two zones and thus water controller with two zones?

Q4: What drippers/emitters should I use? I am thinking of using dripline for all the trees while drippers on the flowers/shrubs. Please suggest what will serve the needs betters. Also will I need any in-line valves to control flow anywhere in this layout?

Q5: Is it recommended to use the pressure reducer on the tap? And also to use back-flow prevention valve to prevent soiled water going back to mains?

Q6: I am planning to use the recycled water for irrigation, I read that it is safe to use for all plants including veggies. Please share if there should be any concerns regarding its use?

I really appreciate help and tips for all experiences gardeners out there. Thanks so much. 

[Jason]

Hi @tanveersattar,

Great to see you undertaking this time-saving (and plant-saving) project and coming up with a detailed plan. Our community members, including the ever-helpful Bunnings D.I.Y. expert @EricL and keen green thumb @robchin, will be more than happy to help. 

While you wait for a response to your questions, I just wanted to make sure you have checked out the comprehensive D.I.Y. Advice series from Bunnings on how to install a new garden irrigation system. One of our resident garden experts @Adam_W has also shared the step-by-step guide How to install a drip irrigation watering system, which includes a video.

There's also some helpful advice in these previous discussions:

• How to install a simple irrigation system by @srobinson 

• Understanding a drip irrigation watering system by @Adam_W 

• Watering system for my backyard by @DryGarden 

• Garden irrigation system by @GardenerJohn 

• Watering system by @Brian 

• Holman BTX1 watering system review by @TheSaltyreefer 

• DIY irrigation system by @lushgardener.

Hope that helps,

Jason

[tanveersattar]

Thanks Jason for sharing these links. I have watched Adam's video and couple of other posts. I will look at others which I have not yet. In my case I am unable to decide on some specifics and need advice. So looking forward to some help. So as you mentioned, I will wait while reading other posts you shared.

Thanks 

[EricL]

Hello @tanveersattar 

Thanks for sharing your question about planning a drip irrigation system. Let me try and answer some of your questions.

• Between a 19mm and 15mm pipe size, I would recommend using the 19mm as it future proofs your line just in case your plants require more water in the future.
   
• I don't think it's necessary to run a separate line, you can branch off if you need more than one line, but that section can be controlled with its own pressure reducer. My thinking on this is you'll need less parts if it is just a single line and fault tracing becomes very easy.
   
• If you do decide to do two lines, you can use separate water controllers for each line.
   
• I suggest sticking to one type of system so that you won't have pressure problems. If you are using drip lines, then its best to use it for the entire garden. If some of your plants require the use of micro sprayers, then its best to have these on their own line.   
   
• I highly recommend using a pressure reducer and back flow preventer on your system.
   
• Your question about using recycled water in the garden has got me thinking. Let me double check with my gardening specialist and I'll get back to you regarding its use on vegetables.

In the meantime, I suggest drawing up a pipeline plan indicating where it will run. This will help you calculate how much pipe you'll need plus, the number of elbows and connectors. It will also address your plan regarding having two lines and two controllers. 

If you have any other questions we can help with, please let us know.

Eric

[tanveersattar]

Hi Eric, 

Thanks for taking time to answer those questions. 

As for Q1: Apologies, I have mistyped polypipe diameter options to be 19 and 15 mm. I wanted to ask about 19 and 25 mm. (Updated my post to clarify that). But if 19mm suffice then I will go with it. 

On Q2/3 (about separate lines): I got your point about simplicity and ease of maintenance, but I am not clear how I can adjust frequency and duration of water delivery to different types of plants using one line. For example, if I run my line to water the vegetables on alternate days, the trees might not need water that frequently so how can I reduce the water delivery to trees on the same line? Is there a way to handle this on one line (unless I put in-line valves and on/off them manually)? Or I can run two lines with two controllers (or a controller with two zone settings) like Holman WX2 or similar. 

Q4: Thanks for suggesting same system on one line (drippers or sprayer), that makes sense to ensure consistent water delivery. 

Q5: I will use the pressure reducer and back-flow preventer. A silly question on that:) Do they go between tap and timer OR between timer and irrigation system?

Q6: About the use of grey water, please let me know when you have more info. I recently read that because it is treated, you need use less fertilizer for the plants as compared to when fresh water is used. It will be good to know. 

I will start with pipe measurements and plan so that I have a list of parts with me. Also need to measure the water flow rate as per Adam's bucket method. 

Regards

[EricL]

Hello @tanveersattar 

Once you've drawn out your pipe plan, you'll immediately see if a single hose system will work with your garden. If you are looking to control the amount of water going through a section of your system, it will be necessary to place a control valve at that junction. If you were to use two independent lines, they will still need controllers specially if you only want one side to function for that day. 

You can use a traditional vacum breaker valve such as the Brasshards 25mm Vacuum Breaker - Suits 20mm Hose Taps. A good example of a pressure regulating valve is the Rain Bird 1" 40 PSI Pressure Regulating Filter, its specifically designed to work with drip irrigation systems.

In regards to recycled water it's ok to use it on vegetables as long as they are thoroughly washed in regular clean water before it is cooked or consumed. However, don't use greywater on your vegetables as it is untreated and contains bacteria and harmful chemicals.

If you need further assistance, please let me know.

Eric

[tanveersattar]

Thanks Eric, 

In case of single main line, control valves need to be manually opened/closed, but with two main lines I can put water timers at the tap and split from the start and thus control them independently (more costly option though). I will draw the plan and see what suits. As with the recycled water, thanks for checking it for me. I will not be using grey water anyway. So all good with the use of recycled water then. And thanks for pressure valve recommendation. 

I think it is time for me to get started

Regards

[EricL]

Hi @tanveersattar 

Once you've finished your pipe plan why not share it with the community. We'll be more than happy to provide additional advice and information.

Eric

[tanveersattar]

Sure Eric.

Here is the draft. I am thinking if I can reduce the drip line loops (at the moment it is one ring around each plant/tree. I may make them straight runs, what you suggest? 

another layout on east and north sides. 

[robchin]

A good project here and well done for being adventurous. You'll benefit a lot from having a sprinkler system or three here. Some awfully good advice already. I would just note that if you are using drippers - you can use an awful lot of them at one time. Most gardeners have30-50 lpm available to them. My favourite dripper is this one: Pope 100mm Trickler Dripper On Spike - Bunnings Australia - you add a bit of spaghetti tube and they have a lot of flexibity - you can tweak the amount of water up or down depending on the size of the plant. They use about 1.5 lpm fully on so you can run 20-30 of them at any time - fully opened. Most run them at much less than that so can run 40-60 at any one time. BUT just because you can - doesn't mean that you should. 

As @EricL has intermated - you should split the system up so that the same plants get the same type of watering. Veges and flowers need watering every day, whilst fruit trees and shrubs might only need watering every 2nd or 3rd day. You might find you end up running parallel lines in your garden beds to get the best effect for your plants. 

My only variation to what Eric has suggested is that I would run the Photinias as a separate line. If I read what you have said right - they will get very different environmental conditions to the plants in the other area so will benefit from having a different watering cycle. Not a big deal - no extra cost - just one extra line at the tap. You'll benefit from one of these; Nylex Brass Four Way Manifold - Bunnings Australia

Veges: I would note that if you have vege patches with lots of plants in them - drippers are impractical - but you can get a good effect with dripper tube - excellent stuff. Pope 13mm x 30m Drip Eze Drip Irrigation Tube - Bunnings Australia have a look at this. 

One final practical tip in relation to pipe sizing. It is only a little bit more expensive to use the bigger 19mm pipe than 13mm - I do like to only have one size of fittings in the shed - makes life so much easier. 

Good luck.