Merri Bee Organic Farm is creating a natural system of perennial
abundance to satisfy human needs in food, shelter, energy , community and
wilderness, whilst restoring a cleared and overgrazed piece of rural land. Our
farm is designed as a ‘closed loop’ in which the yields and by-products of one
system are used to satisfy the needs of another, constantly circulating
nutrients and harvesting water and energy via multiple elements. We aim to
protect soil biodiversity and its many ecological functions. We are exploring
and demonstrating these principles, educating and inspiring people to
perpetuate the building of sustainable infrastructure. An example of this is
wicking beds
We set up a wicking bed in a hurry recently to
demonstrate how little water it takes to grow veges in this set up The growth has been
phenomenal.... lettuce seedlings of the same size were planted in an
adjacent, well watered and composted garden. The garden has had to be watered (
with a butterfly sprinkler ) once a week , the wicking bed only once a month.
The lettuce in the wicking bed are 3 times the size of the garden lettuce. We
dug a 150 ml deep level pit, lined it with black plastic and laid a 90 ml old
storm water pipe we found at the tip on that .
We had previously cut numerous slots in the pipe and positioned
the slots downwards, so the pipe won’t fill up with dirt. We put a plastic bag
and a rubber band over the end of the pipe. Conveniently the pipe from the tip
came with a 90 degree bend ( elbow )
attached. We inserted another length of pipe in it, and set that up vertically.
That’s your water filling pipe. We then
surrounded the pipe with small rocks at one end and woodchips at the other.
The woodchips were much lighter and easier to work with . I will
see which end works best for the longest time. So you now have the 150 ml pit
filled with aggregate which creates big air spaces between chunks, which will
often be full of water. The aggregate essentially holds up the soil above.
Place a thick layer of leaves or grass clippings , or a sheet of shade cloth on
top of the woodchips or rocks. Then fill the bed with good soil and compost mix
to a 350 ml depth. It can be up to 400 deep but no more, as the water can only
wick up to a height of 400 or so. 350 is deep enough for most root zones. A
drainage hole is essential at the
level of the shadecloth. Otherwise a down pour or forgotten hose running would result in waterlogged plants. Which will die. You then hose or bucket water into your plastic lined gravel
or wood chip-filled reservoir , via the fill pipe until water starts emanating from the drainage
hole . In the event of a down pour, this drainage pipe or hole will ensure
the soil doesn’t become waterlogged. In our case, water just begins leaking out
at ground level (where the plastic liner emerges) when the reservoir is full. I like the fact I can go away and
pick some parsley while the running hose fills the reservoir. If I get carried
away birdwatching the excess water will only benefit plants down hill of the bed.
After all this work and materials, plant your seedlings and water
them in as usual.
Prepare to be amazed as they thrive without any further attention
from you for at least a month. That’s what we found, and we certainly hadn't had much rain. See pics of the plants in the wicking bed just one month later, compared to the pale undersized lettuce in garden ( which had been watered with over head sprinkler every second day) My
photography sucks, but I hope you can see the bigger and lusher growth in the
wicking bed. Tried to deliver same amount of compost to both lots of plants also. I think the sprinkler watered lettuce bolted to seed soon after the picture was taken.
We
want to experiment with wicking beds as a grey water treatment system, having trickled it first through a rock column then through a wicking bed planted with reeds to remove nutrients . The reeds could be used for mulch.
A google search will reveal many different types of wicking beds and no doubt YOU will come up with great innovative ideas we would love to hear! My
friend Tash Levy has successfully used bentonite clay instead of a plastic
liner. We will be following her lead on our next one, as it is more natural and
less toxic to manufacture and use than plastic. Thanks Tash!
Update! EDMP
plastic is safer than PVC. Pond liners of EDM or butyl rubber would be of the safest kind of plastic
and possibly worth the extra expense. We will also incorporate a worm feeding station
for disposal of vege scraps.
Every home in arid lands should have a wicking bed!
Here is some further great info from Rob and Michelle Avis in Alberta
Canada: http://www.energybulletin.net/stories/2011-05-31/bottom-diy-guide-wicking-beds
How Wicking Beds Work
A wick
works through capillary action – the same force you observe when you dip a
piece of tissue paper partially into a glass of water and watch the water climb
the paper. Wicking occurs in many materials; cotton, wool, geo-textile,
soil, gravel and even wood to some degree. Every material has different wicking
properties which you can test by placing that material into a glass of water
and watching the water “climb” up. When one end of the wick is saturated and
the other end is dry, it creates a moisture gradient, which drives the wick
until the gradient no longer exists or you run out of water. With the earth
box, one of the more
popular examples in North America, the soil is suspended above the reservoir
with wicks dangling into the reservoir pulling up moisture. As the plants use
the moisture in the soil, it creates a moisture gradient (the soil is drier
than the reservoir) which drives moisture through the wick into the soil.
Advantages of Wicking Beds
Wicking beds have a lot of advantages over standard
raised beds and in-grown swale-based gardens:
·
They are water-efficient! Watering
from the bottom up prevents evaporation of surface water (which occurs when you
water beds from the top).
·
They are self-watering! Wicking beds
are an especially great system to use in community gardens because they save
people from driving every day during hot weeks to water their beds. A full
wicking bed should irrigate itself for about a week.
·
·
No evaporation means no salting of
soil. If you are watering your soils from the top with slightly water, you risk accumulating salts, because the water evaporates and leaves the
minerals behind. Eventually your soil will struggle to support plant life.
·
They provide a lot of drainage in the
event of a large downpour.
·
Since they're raised, they will warm
up quicker in the spring.
·
You can easily attach cold frames or shade sails or birdnets to
them.
·
They are great for people with less mobility/flexibiity.
·
Disadvantages of Wicking Beds
· Are few! *They cost more in time and perhaps materials to create than ordinary garden beds .
* You can forget to water them
altogether !
UPDATE
U
UPDATE
Our first wicking bed is going well, devoted to strawberries now. Second
one has had a major problem.. I HAVE TO FIND TIME TO EXCAVATE a large amount of soil out and see what is
going on, because the reservoir always has water in it, it isnt going anywhere,
but the soil is dry. Somehow poplar roots from a nearby huge tree have also invaded it ,without piercing the plastic
obviously, maybe through the jarrah sleeper joints? So it is all a mystery.
I have done a small wicking bed lined with clay, it is going very well . I
think the reservoir need filling more often and certainly doesn’t hold water
for more than half a day but I think that means I didn’t use solid enough clay.
It has a certain amount of sand in it. I used bentonite (as in no name brand kitty litter) , dry, as a
layer over the wet clay, to faciitate a light pounding of the clay "pond
liner" . It stopped my pounder getting heavy with sticky wet clay.
Even though it only holds water
for a few hours it is long enough for the soil above to wick it up. And for
some reason, it doesn’t dry out for a week in high summer. No doubt during the
other 3 quarters of the year it will barely
need water. I did put quality aerobic compost in at a rate
of about 50 %. The strawberrys in this mini wicking bed with glass viewing
window are growing well.
C Could there be problems with anaerobic conditions in the bottom layer of
soil near the water reservoir? The rules are that you look down the pipe every
few days and check the water level. You should only water again when the pipe
has been dry for 1 to 3 days. If people are experiencing problems with anaerobic
conditions they may be over watering.
In our non wetting soil, the major advantage to wicking beds is being
able to drop the hose going full bore into
a big pipe and go off and do something else for 5 minutes while it fills. You
know the water is going right where your intended plant recipients are, and
they are going to get every drop. It is
not going to grow weeds, the water isnt germinating weeds.
Anything that save us water and time is worthwhile
in my book.
U