5. Good Organic Gardening - September-October 2016 AvxHome.in

Wicking bed design | THE SHED
Words & photos Sandra Tuszynska
In the previous issue we covered Phil and
Carmel Pate’s garden and in that story
we mentioned Phil’s superb wicking
bed design. Phil is a jack-of-all-trades:
plumber/gasfitter, builder and designer.
Whatever Phil does he does with great care and
precision. His wicking beds are no exception.
Wicking beds are a great way to ensure
constant and even water availability to garden
crops. They eliminate evaporation and are
designed to deliver water to plants from below
the roots. Their functioning is dependent on
the water reservoir below the soil, which is filled
with material able to transfer water to the soil
through the process of wicking.
Wicking from the reservoir to the soil
depends on capillary action of water, or the
cohesion between water molecules and the
surrounding medium, such as sand or organic
material, which has minute spaces between
its particles to allow water molecules to move
through them, thereby creating a cohesive water
column. If the spaces are too large, the water
column fails to form and wicking cannot occur.
Wicking of water is limited to 30cm in height.
For this reason, the maximum depth of the
water reservoir should be 30cm. The soil placed
above it will likewise wick up to 30cm of water
but its depth could be extended to 50cm, as
plant roots take up water from the soil.
There are several wicking bed designs
that work well, providing they have a water
reservoir, a water delivery pipe that reaches the
reservoir and an overflow pipe that prevents
the soil from becoming waterlogged. Phil has
designed an elaborate but practical wicking
bed system that makes gardening a snack.
How Phil did it
1, 2, 3, 4. Phil sourced some Colorbond steel
roofing to fit his 3m × 2m × 0.6m wicking
bed design. The beds are held by a hollow
50mm × 50mm steel frame. The space is
lined with some old carpet, fluffy side up,
attached by tek screws all the way to the top
of the frame. This provides protection for
the polythene builder’s liner, which forms the
water reservoir for the wicking beds. The liner
is further protected from above with another
layer of carpet, this time fluffy side down.
1
2 3
Wicking of water is limited to
30cm in height. For this reason,
the maximum depth of the
water reservoir should be 30cm.
4
Good Organic Gardening | 67