As part of my drive towards sustainability, making use of our bit of land and getting fit (see Mick’s Eco-Gym) I have been creating a ‘veggie patch’.
But this is no ordinary plot this is a technological wonder known as a ‘wicked bed’ (pronounced wickt rather than wick-ed). I am thankful to an article from the Alternative Technology Association for the design. The design is based on having a 50mm reservoir of water across the whole area and beats traditional beds in that
- It is very water efficient – evaporation from the surface is much reduced
- The plants have a constant supply of water – even through the hottest days
- Watering is simple matter of adding water through a pipe at one end – no spraying everywhere and hoping that you get sufficient to the plants
- You can add water in direct sunlight without the risk of leaf burn
- The plants get the right amount of water through a wicking action from the reservoir
- You cannot over water – as an overflow pipe allows excess water to drain away
- The construction stops tree roots from invading the bed
- Rabbit proofing is easier with the raised bed
Construction
I had decided to go for an ambitious start with a bed measuring 6 metres by 2.4 metres by 0.4 metres high (2 sleepers). But, since the bed requires a level base for the water reservoir and we have a 15 degree slope this meant an awful lot of fill to get the level. Fortunately I had the fill from the cut for the tank I had put in earlier.
The level needs to be within 25mm across the surface, it is worth spending some time to get it a near right as possible.
I created the frame using treated pine sleepers which I joined with simple butt joints and coach screws.
Builders heavy duty plastic membrane is is a perfect 3metres wide. A single sheet creates the reservoir but you must be careful not to puncture it. So I laid old carpet underlay of the compacted fill before putting down the membrane.
Another layer of old underlay went on top of the membrane.
Then it was time to create the reservoir which was done with gravel to an approximate depth of 50mm. I filled the reservoir with water and got a final level on the gravel, making sure that there was at least 50mm of gravel/water at all points over the bed. Notice the overflow pipe fitted just above the normal water level.
The final and very important layer was now put on which was old carpet. This forms a barrier which stops the soil dropping down into the gravel/water reservoir but allows water to be carried up into the soil above.
Last task before loading in the soil was to put a 90mm water filling pipe in the corner vertically and just raised over the top of the soil level. I made a mistake here by not putting this pipe through the carpet which significantly slows the rate at which I can re-fill the bed.
The 6 cubic metres of quality soil then needed to be loaded in and leveled.
Young Phil gave a hand to level and we celebrated completion by planting some Royal Blue potatoes.
Of course, all local gardners know the problem that anything growing tender new shoots becomes a treat for rabbits, posums and parrots. The wicked bed was secured against invaders with a wooden frame, chiken wire and vine netting.
Planting
To date my wicked veggie patch is has been planted with a variety of heirloom seeds from Send-Me-Seeds-Pip
including kale, beans, beetroot, snow peas, rocket, squash, courgettes, shallots, broccoli, lettuce, celery, tomatoes, and spinach.
Last week I pulled the first potato (too early) but with some salad leaves from the patch we had our first home grown WICKED POTATO SALAD – we are looking forward to a summer of home grown salads and veggies

[...] Also some good info at the Warrandyte chat blog here. [...]