No rest for the 'wicking' with these beds

What does an old tank and a recycled fence have to do with growing your own food? A lot! If you are interested in doing more with less and saving water that is.

We spent the recent Recreation Day long weekend making several wicking beds for one of our favourite 'clients', Aunty Trish. Trish is renting her home but wanted to get more our of her garden. So we designed a plan featuring containerised plants that could be transported if and when Trish has to move out of that home.

The heroes of this plan are definitely the wicking beds we made, using two recycled food grade intermediate bulk container (IBC) tanks and several sections of the property's fence that Trish had salvaged when the landlord replaced it. Trish was keen to grow her own food but wanted a fairly low maintenance set up. The wicking beds have a water reservoir at their base meaning less need to water on a regular basis.

TIP: You still need to water in plants at establishment to ensure that the soil profile is wet right through and to enable water to move up into the soil profile from the water reservoir.

As well as the IBC tanks and recycled fence palings, we used a premium veggie mix from a local supplier as our soil profile and blue metal screenings in the water reservoir. Ideally we would like to have used scoria in the water reservoir. This volcanic material is porous and has an excellent water holding capacity and air filled porosity. However, it is not readily available in Tasmania, and if it is, is very expensive.

Before we filled the wicking beds with these materials, we conducted a test to make sure that there were no leaks in the tanks.

Then we shovelled the screenings into the wheelbarrow, tipped them into the tank, returned to the screening pile and shovelled another barrow load. I think you get the picture! There was a fair bit of shovelling involved, but what a great outcome.

Below you can also see that we placed the slotted agi (agricultural) pipe) at the base of the tank before we poured the screenings over it. This pipe was attached to a drainage pipe positioned vertically to enable Trish to top up the water reservoir as required. We then covered the screenings with a geotextile fabric that will stop the soil migrating into the water reservoir.

Then comes the 'soil'. In this case, we used a premium veggie mix which should get Trish's vegetables off to a good start. Given this is an organic material, and the plants will take up nutrients from it, this soil profile will need to be topped up over time. That is natural. Well rotted compost should do the trick when the times comes.

After a bit more shovelling, we were ready to wrap the tank with sections of the old paling fence that were able to be reused. Instead of hiding the tank totally behind timber, we integrated the old palings into its structure. I like the fact that you can still see the original tank structure. It is a bit like the Centre Georges Pompidou, the structure is not hidden but forms part of the aesthetic.