In recent months, after drought, fire and flood, I have had questions from friends and family and clients about wicking beds – What they are and would it be a benefit to them in their context.
Wicking beds are something I use here at home, alongside other growing techniques, that help contribute to the productivity of my home. They are something I recommend to my clients. I have helped build on several occasions in different areas using different materials.
In a nutshell, a wicking bed is an enclosed garden bed that has a water reservoir on the bottom, and that this supplies the water for the plants growing above. The water wicks up through the soil so that it is watered from below rather than over saving time, is very water efficient. I have found it can survive our more extreme summers and still be productive.
Wicking beds were invented by Colin Austin an Australian inventor and entrepreneur who was concerned about the use of one of the worlds most precious resources in the way we grew our food – Water.
After much thought, design and concepts, he ultimately came up with this system that can revolutionise the way we grow food in our home gardens.
The real secret to the success of the wicking bed is to maintain the moisture levels of the beds at a more consistent rate, rather than the ebb and flow that can happen with the watering of our gardens – Too much (flood) or drought (not enough)
Some basic rules of thumb for wicking beds are always remember that the water will only wick up approx. 30cm. You need to have a hole in the side of the container at the reservoir level so that any excess water will overflow rather than build up and drown your soil and plants
There are several methods we can use to construct a wicking bed.
Something as simple as a polystyrene box, garden pots on the bottom, creating the water storage and then a piece of shade cloth, then the soil placed on top. The water wicks up the shade cloth and through the ground providing the plants with the water they need.
One of the most popular is using a 1000L tank (IBC) that can be cut in half and then divide the bottom half between the water storage and the top half soil. You can use river sand, works well though it can restrict the amount of water the reservoir can hold due to the small space between the sand particles. Another popular method is to use 20mm blue metal rock which will have a larger spacing for water. One thing to take into consideration is that sometimes broken up concrete can be mixed in with the blue metal and the lime within it can alter the PH over some time.
The third method I have been using, more so lately than in the past, is a method I was introduced to by Costa and his show ‘Costa’s Gardening Odyssey’ which used to show on SBS in what seems an age ago.
Using an older sealed packing crate, which interestingly enough can hold 9 old milk crates which will create the water storage. Then using geotextile fabric to drape over the top and the side of the milk crates makes the wick and also separates the soil from the water storage. Then place the soil on top
Benefits of a wicking bed
• Uses up to 50% less water than conventional veg gardens
• Less water lost through evaporation
• Low maintenance
• Less risk of under or overwatering
• Plants get the exact amount of water they need, and their roots stay cool
• Soil remains moist most of the time
• Allows for thick mulching which also decreases evaporation
• Improves soil quality through moisture, cycling nutrients
(nothing washes away)
• Can be made cheaply
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