Friday, October 12, 2012

Everything you need to know about irrigation

Ok, so it might not be everything, but I have certainly learnt more than I planned to. Last summer we used a little sprinkler on a stick that I moved from bed to bed. It worked well, except it required constant manual attention, and left an untidy hose always lying around for me to trip over. So for this summer we decided to lay ground irrigation.


I did some online research and discovered soaker hose. A soaker hose has thousands of tiny holes all over that weeps water like sweat from our skin. This sounded perfect for a vegetable garden, and I loved knowing it was made from recycled car tyres. However look what happened...


The front of the bed was soaking allright, but the back was bone dry. The water obviously runs to the lowest point in the hose and leaks from there. Looking at the manufacturer's website, they openly admit it doesn't work on slopes. Evidently not even mild slopes like mine.


Not wanting to waste my time, my money, and the worlds resources, I thought I would see if I could get it to work. So I tried laying it snake like, that did improve the problem, not perfectly, but would suffice. But this was only a test on one bed. What would happen once I had completed the irrigation on all 6 beds? My assumption, and it is only an assumption, is that the beds at the bottom of the hill would get the most flow. Spending more time and money to test my theory was something I was not willing to do, so...


I purchased a small role of dripper hose, just one mind you, and tested that. The manufacturer claims an even flow from every dripper even on slopes. From my testing it looks like their claim is accurate. Most importantly I get to have the hose laid out in a spiral again, and I do like spirals.

Speaking of the spiral layout... to calculate the length of pipe required for each spiral, I used a free online tool - Spiral Coil Calculator. It’s real purpose is for calculating the induction of electrical coils. I bet the creators never thought it would be used for irrigation purposes. It was a stroke of luck, or good fortune, that the length I required, 15 meters per spiral, is the exact length that the hose is produced in.


The recommended distance between the hose is one foot (30cm).


Each dripper spiral is connected to a black plastic pipe that runs from the tap and around the back of the garden beds. So far only two beds are connect in, but apparently a single domestic water tap should be able to supply up to a 100 meters of dripper irrigation. If it turns out that this is not the case, I will split the garden onto two separate lines. Hopefully I won’t have to.


The dripper hose is connected to the main line using a standard garden hose pipe connector. I did this so that the dripper hose can be removed from the bed when the chickens are working the bed and then when the bed is racked and prepared. From what I have read both dripper and soaker hose will become blocked over time, and was recommended they be cleaned every year or two. This can be done using a bit of hot soapy water in a kids swimming pool. Having the dripper hose detachable enables this.

When a hose is removed from the system we will replace it with an end cap so that the rest of the beds can continue to be watered.


At the tap end, we have a digital water timer so the task of watering can be completely automated. Connect to that is a pressure regulator that prevents the hose joints from bursting under too much pressure. Below that is a water filter to catch any particles that might otherwise end up blocking the drippers.

I have always enjoyed manual watering, finding it quite relaxing, but I am looking forward to putting that time towards other gardening tasks. Finally a big thanks to my gardening group for all their help.

8 comments:

  1. We do something similar - our main loop goes under the path, and hooks up to removable loops in the beds (that come out when the chooks are on). Our attaches to our water tanks - amazing how much water these gardens consume!

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    1. I will admit yours was probably where I got the inspiration.

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    2. Really? I'll let Pete know, he'll be chuffed. We were daft - our garden nearly dried to a crisp before we realised it just needed water! :)

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  2. An idea that came to mind reading this, using a normal water hose or similar (not weeper), connect both ends of the weeper together. The pressure from tap runs to both ends.

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    1. That probably would help to a degree, sadly it was the entire top half of the spiral that lacked water pressure, not the end of the hose.

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  3. I use dripper hose too, the brown stuff with little holes every 30 cm. I have a manual timer, the automated one looks good. How are your chooks going?

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    1. Once set up the auto timer is great. This timer is one that has been sitting at the back of a shelf in the garage for some years. The LCD screen is bung and almost impossible to read. When setting the time I have to count the number of presses I make, and hope I got it right. As it is coming on at the right time, I guess I did.

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    2. BTW, the chickens are fine. There have been more dramas, I will post more on this.

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