Raised ponds and wicking bed

Discussion in 'Designing, building, making and powering your life' started by PermaGuinea, Mar 11, 2014.

  1. PermaGuinea

    PermaGuinea Junior Member

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    Late last year, with the help of helpxers, we built a raised garden bed out of cinder blocks. Originally I had planned to make three wicking beds that overflowed into each other downhill to conserve water, but midway through the project my wife said "we don't need three wicking beds", so I modified the design to include a lotus pond, a water chestnut pond, and a wicking bed. The finished design is three tiers high - the lotus pond is three blocks deep, the water chestnut pond is two blocks deep, and the reservoir for the wicking bed is one block deep. It actually now overflows "uphill" (we wanted the greens close to the back steps) and the overall look of the thing is very Escheresque:

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    Having the ponds raised is good for keeping cane toads out. At three tiers high, the water pressure actually pushes the middle block out so there are a couple of hidden star pickets bracing the walls from inside.

    We stocked the ponds with some native vegetation and small fish from our dam to keep the mosquitoes from breeding.

    Besides making a nice feature and having a pretty flower, the roots of the lotus (a plant native to Australia as well as Asia) are edible and very tasty in Asian cooking.

    [​IMG]

    The purple floating weed is azolla pinnata. It is a nitrogen fixer and when it proliferates, you can throw it to the chooks as feed or use it as mulch on the garden beds. (The lotus leaves are now all about thirty centimetres across and stand right up out of the water, as some had started to do when I took this picture.)

    This is the water chestnut pond:

    [​IMG]

    The water is about ten to fifteen centimetres deep and the soil is about fifteen to twenty centimetres. Here the azolla completely covers the water, discouraging mosquitoes. There is also satoimo, a Japanese mini-taro planted, but I don't think it really likes its feet this wet.:shake:

    [​IMG]

    This is the wicking bed. It has a ten-centimetre reservoir of gravel at the bottom and then a mixture of coir and soil on top, with a higher ratio of coir near the bottom gradually changing to more soil near the top. Watering is done by filling the reservoir through the pipe at the back right-hand corner. The water level can be checked by looking inside the pipe (the gravel is visible) or by removing the lighter half-paver at the front which is where the reservoir overflows.

    We are now in our driest summer drought on record for our region. Last year was bad but this year is worse. Most of our garden has withered in the heat and dry, even with constant watering. The greenest spot on our property is now the wicking bed and my wife wishes we had have made three of them - but I am still looking forward to a good feed of lotus root. :)



    This is just one of the improvements we have made to our place.


    Our house is for sale here: https://forums.permaculturenews.org...nd-for-Sale-at-Mothar-Mountain-via-Gympie-QLD
     
  2. Rick Larson

    Rick Larson Junior Member

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    Ingenious to have the water overflow uphill!

    How does the water overflow from one tank to the other?
    How much water does it take to maintain the system - say on a hot day?
     
  3. PermaGuinea

    PermaGuinea Junior Member

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    It is only possible because the height of the lotus pond is three blocks, the height of the middle pond is two blocks, and the height of the wicking bed reservoir is one block.

    At the uphill end of each pond, I left out a half block and then using three pavers I made a spillway that was below the rim of that pond by about four centimetres (1.5 inches). That way each pond overflows at the uphill end before breaching the rim.

    We still water the wicking bed daily from above, but it doesn't need as much water because the soil retains its moisture better with the reservoir underneath.

    As for the ponds, they dropped about a centimetre a day at first, so I topped them up every four or five days. The pond surfaces are 1 m x 1.4 m, so that is about 70 litres (18.5 USgal), I think. There is less evaporation now that the vegetation has matured and is shading the water.
     
  4. Rick Larson

    Rick Larson Junior Member

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    Excellent. I'm going to try this method. Thanks a lot!
     
  5. eco4560

    eco4560 New Member

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    Nice! You might want to retrofit them back into wicking beds even…

    I had lotus root soup in Cambodia. Yummy.
     
  6. PermaGuinea

    PermaGuinea Junior Member

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    :)

    Yes, at some point I may do just that, depending on how tasty we find the water chestnuts. :D

    It would simply be a matter of emptying the bed, making some holes or a slit in the pool liner at the height of the new wicking bed reservoir, filling the reservoir with gravel, standing an input pipe on the gravel, and then building up the soil and coir mix to the desired height.

    Since the blocks are (mostly) only stacked, not fixed (except where I've put in star pickets, the structure could also be partially dismantled and rearranged to add a new spillway, or an extension, etc. You could also add modules to make it longer or turn it into a T-shaped or L-shaped garden for instance. It is like playing with Lego.:giggle:


    I also forgot to mention, we get our blocks cheap by buying "seconds" at the local brickworks (when we are in too much of a hurry to wait for freebies). Most of our pavers came from the driveway of a house site my builder mate was demolishing, some were "freecycled", and others were bought very cheaply second hand online. If you see a builder laying pavers anywhere, stop and ask what they plan to do with the leftovers, because they almost always end up with a surplus. Pavers are great for keeping out weeds and reducing lawn mowing area.
     
  7. eco4560

    eco4560 New Member

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    I love Freecycle - the Sunny Coast one seems particularly successful. I have someone picking up games my kids no longer play with today. Earlier in the week it was a roll of shade cloth that someone wanted and I had spare. I got myself a new kettle when the last one died. With the right tools at the fingers people can be generous and kind in their community once again.
     
  8. bazman

    bazman Junior Member

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    They still play jenga with those wooden blocks you found?
     
  9. eco4560

    eco4560 New Member

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    I actually did have some wooden blocks in the box of toys! This week I have managed to find a washing machine to replace my one that died - just gotta go pick it up and get rid of the old one.
     
  10. PermaGuinea

    PermaGuinea Junior Member

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    Just a note to add, with the benefit of hindsight, don't put the parrot's feather (top left and bottom right in the photo of the lotus pond) into your lotus or watershestnut ponds. It tends to take over and the roots smother the bottom - not good for the lotus root or water chestnut yield.

    It is, however, a good mulch plant for the garden in the drier months, so we set up a separate little pond for it using an old plastic shell pond. As it proliferates, we tear off handfuls of fronds and place them around the base of plants that are particularly suffering from the dry and the heat. It acts like a light sponge to retain water and as a shade for the underlying soil against harsh evaporation from the intense sunlight towards the end of our dry season.

    In contrast, the purple floating weed, azolla pinnata, is fine. It covers the surface between the other plants and forms a barrier against evaporation in the ponds but doesn't affect yield. It is also a good mulch.
     

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