Design Specifications

Galvanised or coated steel raised garden beds of various dimensions are also commonly used as long as they are of adequate depth. Typically something around 70cm (28”) high works well as this allows for a good depth of soil, and enough of a lip above the soil level to hold mulch in place.

If using a small container which isn’t that deep you wont be needing a 20cm (8”) deep water reservoir, you can scale it down to suit the dimensions of the container.

The L=shaped inlet pipe is put into place before the scoria is laid down, it serves as a water inlet to fill the water reservoir with water. The vertical pipe is joined to the horizontal pipe with a 90-degree elbow join. The lower horizontal pipe has holes drilled right along its length so water drains out more easily.

The scoria layer is covered with geotextile fabric or shade cloth to keep the soil layer above it from falling into the scoria layer water reservoir – essentially it is a barrier that separates the water below from the soil above.

The soil then fills the bed to a level just below the edge of the pond liner, so the pond liber sits slightly higher than the soil level.

The wicking bed is filled with water from the inlet pipe to fill the water reservoir, when it is full, some water will flow out of the overflow outlet. The water will then wick upwards as high as it can to keep the soil damp.

Multiple applications

Garden beds in my opinion, much like hydroponic systems, are best suited to growing annual vegetables, which are so short lived they don’t live long enough to develop long term problems due to the soil conditions, and require large amounts of nutrients in a short period. Since wicking beds retain fertiliser all too readily, less fertiliser can be used for annual vegie growing. As such, wicking beds make great intensive vegie beds and kitchen garden beds.

Water recycling

The water that flows out of the water overflow outlet will be loaded with fertiliser so you can run that water into a bog garden, reed bed system or a garden bed in the ground for moisture loving plants (if you get enough water overflowing!)

Extra growing space

Garden beds, like other raised beds, can support frames or trellises to grow climbing plants on such as beans, peas, cucumbers, watermelon and any other edible annual climber you fancy. Keep in mind that you cant hammer stakes or poles into the wicking bed itself, that will punctuate the pond liner and destroy the watering system. The frame, trellis or support has to either be anchored into the ground or attached to a wall behind the garden bed.​