.  Place a layer of sand at the bottom to
   stop stones making holes.
.  Cut and place a plastic liner.
.  Make and place the fill pipe.
.  Fill the bed with a 100mm layer of soil.
.  Cut two 10-12cm lengths of 40mm pipe
   and place them between the plastic
   and the metal at each side as
.  Place a short bit of timber covered with
   some shadecloth under the pipes and
   partly outside the bed as indicator.
   (When the pipe overflows, the timber
   gets wet and we know the bed is full.
.  Place four or more layers of folded
   shadecloth over the pipes to stop the
   soil filling them up.
.  Then fill the bed with soil and fill the
.  Saturate the bed once from the top,
   plant the crop and the job is done.
.  This bed has worked well for five years.
Wicking bed being made at a permaculture centre in Alice Springs
Wicking bed in Mali, West Africa, later used to grow early tomato seedlings for sale. They bring a better price.
All garden beds can be converted to wicking systems, be they metal ones available from hardware stores, rock beds or even concrete laundry tubs and baths.
We converted a concrete laundry tub to three wicking beds. It involved gluing a short drainage pipe into the drain hole of the tub with silica and then placing the fill pipe over that.

The first step was to measure the length of each reservoir and marking these on a length of 90 mm PVC drain.

We then measured the exact position of the tub drains.
We marked that on the PVC pipe and cut 40mm holes. After filing out a bit more they fitted the drain pipe.

We then cut two 100mm holes within each reservoir at the same side as the drain holes.

Next was to measure how long a drain pipe would be, about 10cm, so that just fitted inside the reservoir and cut three lengths of  of 40mm PVC pipe.

We then drilled the holes for a 40mm PVC fill pipe at the end of the pipe away from the drain holes and on the opposite side of the other holes.

We cut the PVC into the right lengths where we had marked them. We use a piece of lino to draw precise circles for cutting.

We cut the fill pipes and after some filing fitted them to the reservoirs.

(We placed the drain pipe temporarily in the reservoir to illustrate the assembled product.)

We closed both ends of each reservoir with duct tape to prevent soil moving into the reservoir.

Next was to glue the drain pipes in place with silica and ensure their was no leak.

Once the silica was set, we placed the reservoir over the drain pipe.

We filled the beds with soil and the reservoir with water. We saturated the soil once from the surface and planted the crops.

The beds work well.

This technique will also work in old baths and any other container with drain holes at the bottom.