You need:
  a drill with hole-cutting drill bit of 100mm for the holes in the
   bottom of the reservoir pipe and a 40 or 50 mm drill bit for
   the hole for the fill pipe at the upper side of the fill pipe;
  a 10 mm drill bit or a sharp kitchen knife to make the
   drain holes;
.  a ruler to get the holes 90-100 mm above the bottom;
  a hacksaw to cut the PVC pipes; and
  a pair of scissors to cut the duct tape.

The box
1. Drill two drain-holes of 10 mm diameter close together 90-100
    mm from the bottom of the box, in the centre of a short side so
    that they open into the top of the reservoir pipe. You can use a
    10 mm drill bit by hand.
    N.B. Two 10mm holes keep the cane toads out, a larger square
    hole cut with a kitchen knife does not. Holes opening into soil,
outside the pipe tend to clog up, especially when there are
worms in the soil.

The water reservoir
2. Cut a length of 90 mm PVC drain pipe to fit reasonably tight
    length-wise into the box; measure carefully as boxes vary in
    length and are sometimes tapered towards the bottom.

3. Cut two large holes in the water reservoir pipe, a bit in from
    each end of the pipe, using the 10mm hole-cutter/drill bit; these
    will let the water out quickly when filling up the box.

4. Cut a hole the size of the outside diameter of the fill pipe near
    one end of the water storage pipe on the opposite side of the
    large holes. Use a hole-cutter slightly smaller than the fill pipe
    and a round file to make sure of a tight fit.

5.  Cover that fill-end of the water storage pipe with duct tape to
     stop soil from washing in.

The fill pipe
6.  Cut the fill pipe, about 500 mm of 40 mm PVC pipe.

Putting it together
7.   Stick the fill pipe into its hole in the water storage pipe.              
      (Use silica if the hole is a bit large.)

8.   Place the water storage pipe in the box, with the large holes
      facing the bottom and with the fill pipe on the side opposite the
      drain holes. Place soil behind the closed end to make sure the
open end fits snuggly against the box.

Filling the box
9.   Mix two handfuls of organic mineral-supplement plus compost,
      well-rotted plant materials or bio-char into two to three buckets
      of good soil, a good potting mix, or a mixture of sand, clay and

10. Fill the box with the soil and the reservoir with water.

11. Plant the seedlings and water them in from the surface to get
      them started, soaking the box.

12. Cover the surface with an appropriate mulch to keep weeds
      down, reduce evaporation and keep the soil cool in summer.
      Good mulch will also become food for the micro-biology, an
      important part of all healthy soils.
The water reservoir with fill pipe with one end taped.
Our current standard  styrofoam wicking box, a recycled broccoli box.

We no longer put hay or material other than soil next to the pipe.

Water spreads just as well wihout any added material.
A white plastic tub made into a wicking box.

The reservoir is the same as above, except that both ends have been sealed to the box with silica.

There is thus no need for duct tape.

The overflow in the form of the drain hole is the same.
For a printable PDF version of how to make a standard box, click here.