Monday, November 14, 2011

Mandala watering system

Now the warmer weather has started so does a new task in the garden... watering. So Saturday morning in a spare 15 minutes before having to go and do some shopping a bee flew into my bonnet. I stomped out to the shed determined that I was going to invent a watering system for our mandala garden in 15 minutes using only what was on hand. And blow me down I did it.

Until building a mandala garden I never realised what a wonderful shape a circle really is. Looking through a bag of disused gardening bits I found an old mental sprinkler. It waters a circular area and our garden beds just happen to also be round. Perfect! But then my face dropped as I realised a sprinkler like this is fine for a lawn but no good for a garden with protruding plants that will block the spray from covering the whole area. But of course put it on a stick and that will raise it above the plants. So I hunted around the shed stopping to take a good look at gardening stake. However how was I going to attach it and besides it would be a right pain to be constantly be inserting and removing it from the ground when I need to move it from one bed to another. So would you believe I found some thin mental pipes, left over from a cheap flimsy piece of furniture, and a piece of dowel that fitted tightly into the bottom of the sprinkler and cleanly into the pipes. I even had more than enough pieces of pipes to install one in the centre of each bed. Could I have been any luckier? The gods where definitely on my side that day.

My watering plan now is that each night I will water one of beds, rotating clockwise as not to cause any friction with the way water likes to rotate in the southern hemisphere. Giving each bed a good deep soak as to last for 6 days. In the case of a heat wave I will probably double the rotation.

In the past I have watered by hand, and even though finding the experience very relaxing, Melanie never felt I gave the ground a good enough soak. She is probably right. And part of the whole idea of implementing this permaculture designed garden is to increase efficiency. While the sprinkler is doing the watering my hands are free to plant out a few seedlings or tie a tomato bush etc. I did think about laying a dripper system but didn’t think it would play nice with the chickens, or should I say I don’t think the chickens would play nice with it.

While using it for the first time I started to question how long I should leave it running. Do I need to give each bed a good hour of soaking or is just 5 minutes ample? It occurred to me I had no idea. The first step I thought would be to calculate how much water the sprinkler delivers. So I turned it on to the desired flow and, getting very wet in the process, I took it off its stand and plonked it in a measuring jug and timed it. It took 12 seconds to fill 2 litters. That’s 6 seconds per litter which is 10 litters per minute. How easy was that maths? As I said the gods where on my side that day.

But now that I know my watering system does 10 litters per minute, how many minutes should each bed get every 6 days?


  1. Oh wow - that looks like a fabulous system. I cannot stand watering, I find it boring as bat manure. I've no idea really about how many litres per bed, but I'm sure that someone will come to your rescue!

  2. Driplines deliver around 1.6L per hour per hole and the holes are spaced at about 30cm. The guy in the shop told me that I'd need to run my dripline system for about 15 mins each time I watered to get a good soak so that makes 400mL per hole/hour. Your garden beds look like they're about 3m wide which gives them a circumference of 9.5m. In a circular bed, you'd ordinarily run 2 parallel lines one at say 9 metres and the other say 5m which is 14m or 42 holes in total. If each hole delivers 400mL/h then it would be 168L in 15mins. get a similar coverage, you'd have to run your sprinkler for 16.8 mins!
    How often you water in 6 days will depend on the weather and time of year but mulching will help retain moisture.
    P.S. I find bat manure fascinating!

  3. Wow you are lucky that you can use sprinklers, we have only, in the last few months, been allowed to water the gardens, other than at 6 in morning on 2 days a week. We are still restricted with only being allowed to use a hose if a trigger nozzle is attached. Oh the days of sprinklers. I see my old ones lying around sometimes.

  4. Ali thanks, simplicity always seems to be the key. I never found it boring but did on occasion find it inconvenient.

    serendipity2000 wooooow! That's some level of calculations you just performed for me. Thanks a million. What I like is it came out to be roughly the answer I was hoping for. I spend 15 minutes in the garden per night so it fits in with that perfectly. I will just work an extra 1.8 minutes.

    dirtandflowers sorry to hear you have such high water restrictions. Here in SA according to the SA Water site we can use sprinklers any day after 5pm. I do think there should be exceptions for food gardeners as it fulfils a basic need compared to ornamental being a want.

  5. We know how many litres. But how many litters do you need?

    I lay drip lines every year. I dismantle and keep the drippers. Just purchasing a new roll of poly pipe (for $5). Very efficient if a little problematic at the beginning getting the flow adjusted. Poly pipe is made from recycled plastic.

    The other investment that is worth it, is a timer tap. They last years. Just buy a good quality one.

  6. I think it basically comes down to X Flow rate x Y minutes = Z litres of water/plant. You know X so you need to find out Z (which will obviously vary from plant to plant so probably best to base on the plant with highest water needs in each bed) to calculate Y. I am pretty sure that Josh Byrne did a segment on this on Gardening Australia…. Or you can do what we do which is basically give them a good soak (ie, in our case, one hour - on low flow drippers) every second day (unless it rains) and every day during a heat wave. Also, it’s better to water the garden before a hot day (I try and do it the night before), rather than after the plants have got cooked/stressed. That said, I would encourage you to consider drippers or ‘holy’ irrigation pipe – you can get rolls of it with a hole every foot or so if you don’t want to set up individual drippers, in fact I have a heap left over if you want some – to better target the roots, reduce weeds and prevent salt build-up on the leaves

  7. sadsac you picked up on my little reading test. Well done! I now know someone actually read the post not just looked at the pictures.

    Wow you lay drippers every year. Does that not take a long time to do? With trying to set up a garden system that is highly efficient I don't think that would work for me. It is good to know that they are made from recycled plastic, I am glad you included that bit of info.

    Alex thanks for that I will see if I can track down Josh Byrne segment on the topic. Re the drippers/holy pipe how do you think it would cope with the chickens? I would want it to be a lay once and forget solution.

  8. Hey Jason, the garden is looking great! Gotta love serendipity!

  9. Hazel's right, your garden is looking wonderful!

    As first time gardeners, watering caught us short last year - that is, we forgot to do it. Eventually we installed two rainwater tanks and a very clever (my husband designed it, so I think it's very clever) modular soaker hose irrigation system that lets us remove the unit from whichever bed the chooks are on at the time. (If you're interested, it's on our Garden page, under "Water")

    Of course, we did that last year for this year's summer - and it hasn't stopped raining yet! :)

  10. celia yes I agree your partner is very clever. I like the modular design. I have however spoken with Debbie who uses soaker hoses and chook dome. She says the chooks do it no harm.


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