Monday, October 29, 2012

To dig or not to dig

That is the question?


When I first started on this wonderful rollercoaster journey called gardening, Melanie and I attended an organic gardening course. One of the concepts that really stood out at the time was the idea that digging was something a gardener should seldom do. Not only is it time consuming and back breaking, but it was said by our teacher, to be not that good for the soil either.

The understanding I walked away with is that soil is living creature, and just like an animal that walks around on it’s surface, is comprised of a complex system of parts, including a digestive system. In the wild food such as fruit and leaves fall the ground. There they are broken down by bacteria and surface dwelling bugs. Even though broken down, this organic material is still not digestible by plants. The mental image that comes to mind, is of the food just being chewed. From here it travels down through the soil, just like a digestive system, slowly broken down bit by bit by various organism that live at different depths within the soil.

Soil has been feeding plants for millions of years, before humans were even a twinkle in mother natures eye, and never required being turned by a spade. All the microscopic organisms have become accustomed to their place in the system and if turned become displaced. The organisms that live nearer the surface for example can not or should not live deeper down, and vise versa. Mixing material in at the wrong level is sure to only result in a stomach ache, loud belches, and smelly farts.

Actually I am not quite kidding there. Our teacher also went on to explain that it can cause the soil to become toxic, and result in unhealthy poorer performing plants.

What was recommended instead of digging and turning was to simply keep adding organic material to the soil surface and allow the soil to digest it naturally. Even if the soil is in very bad condition, it was recommended to just keep pouring on the goodness, and eventually that soil will come back to life.



After Ginger and Diggie (chickens) did a hopeless job at clearing and preparing this bed, I had to. The soil had obviously become quite depleted of organic matter and had become compacted. This made a very difficult job of pulling the weeds and grass. I used a fork to loosen the soil but was careful to not turn. Once cleared I poured on some good quality compost, from SA Composters, and again did not turn it in, just left in on the surface.

Then again... is compost a material that is already broken down far enough, and is thus suitable for turning in? But even if it is, is there any benefit in turning it in? What's your thoughts on the topic?

13 comments:

  1. No dig.

    Homemade compost is chock full of living things and should be covered over with mulch to make sure the sunlight doesn't kill the microorganisms. Shop bought on the other hand will have been fumigated, so would have lost most of these beneficial little critters.

    Have you thought about running a green manure crop on the bed and sending the chooks back on for a second round?

    Definitely no dig :-)

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  2. Well that is very interesting about shop brought compost being fumigated. I assume it is a health precaution. But I wonder if this a blanket precaution to cater for a small minority of suppliers that short cut the compost process.

    Good idea to run green manure, but alas the chickens have still got three more beds to prepare before summer hits. Even though only two chicken went to work on this bed, the previous crop was mostly worked in, along with a good amount of kitchen scraps and azola from the pond. Hopefully that's enough.

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  3. When I moved to my home 3 years ago I had shocking clay or sandy soil all over, nothing in between. After 3 years of "lasagne" type gardening I have the most beautiful rich soil that grows anything.

    I don't do anything fancy, I simply throw all my small prunings around the beds, throw the chook manure on, and cover with pea straw once a year. I make my own compost and that too gets thrown around once ready.

    For me, gardens are meant to be places of relaxation and easy, not hard work. The only turning over that goes on here is if I pull a weed out :)

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  4. Thanks Molly for sharing. Your garden is living proof that no-dig works.

    Why is turning the soil done by farmers, I wonder?

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  5. No dig for me, but that is because I'm lazy. I did dig when I first set up the garden, but I have a heavy clay soil and dug in sand and compost to lighten the soil. The areas that got this treatment do much better than those that I just planted into without digging the soil over.

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    1. Now that's interesting, you have given an example of where turning over has worked for you. Did the other area (non-dig) get a treatment but added to the surface?

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  6. I just pulled out the last of the winter veg and am replanting with tomatoes. I noticed when I dug it over that there were lots of holes where the worms had been. Linda Woodrow talks about not disturbing the soil in her book so that the water can travel down the little tunnels. I should have followed her advice instead of turning the soil.

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    1. That's a good point about the worm tunnels. Yes of course digging would destroy them. I think the desire to turn over is because it makes the soil look more fertile, but maybe that's only an allusion.

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  7. I've also read that you don't want to disturb the worm tunnels as they will begin again in establishing them, rather than focusing on improving the soil for you. Then there's the ecosystem on top of that. I also try not to walk on the soil (though my husband makes fun of me whenever he sees Costa or Tino do it on Gardening Australia) so as not to compact and effect the ecosystem either. I put the organic matter on top, though I do heap a row up before I do that, then mulch on the top of the row with the compost and other green matter, as well as the new paths. Whenever I weed, I throw these onto the paths so they will be mulched as well. If I ever get lazy and don't mulch enough, you can see how much it depletes the soil, but when I mulch well, it looks amazing underneath.

    We have a veggie patch system where we let the chickens in and out of each of the six paddocks every few months and they have a large (10m x 10m) run in the middle. That way we get the clearing work and the fertilising done. Then the reason we use rows, though not very permie, is for the irrigation lines. I do plant herbs and beneficial plants around the edge that the chooks leave alone. And this system seems to work for us. We do also grow green manure in situ a couple of times a year.

    Sandy

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    1. It sounds like you got a similar system going there. Six paddocks, instead of six beds. I like the sound of the central chook run. I am imagining you have six gates from the central run into the paddocks.

      Back on the topic of no-dig... that is very interesting about the worm tunnels, that never occurred to me. I guess digging would be like putting a bomb in a busy city subway.

      And you are not alone with trying to avoid walking on the beds. I do believe it makes a difference, but sometimes very hard to avoid. Having rows would help you with that.

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    2. Hi Jason
      Yep, we do have a series of gate (which are actually just wire fencing sometimes) and we've used el-cheapo archways from Bunnings to frame the gate and also to grow bee attracting climbers over. They haven't grown all the way over yet, but will be gorgeous when they have. And in terms of paths, I do throw any weeds I pull out on to the paths so that they are mulched and giving back a bit of organic matter next to the beds as well. But I agree, we seem to be running similar systems, just on a different scale. And I enjoy visiting your blog, so thanks for the effort.

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  8. interesting thoughts. I do dig my green manure crops in so wonder what people do with their green manure crops if they don't dig.

    Generally, digging over does move the humus rich top soil down lower which is not ideal plus changes temporarily the movement of water through the soil (up and down) and the water holding capacity of the soil.

    I still think there is a place for digging. After seeing Peter Cundall's garden of digging for a lifetime, he has soils teeming with life so I don't think we can say digging is necessarily all that bad either? Interesting topic all round.

    Dave
    http://tassiegerminations.blogspot.com.au/

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