As I’m away 3 days a week, looking after a veggie patch could be a problem. How was I going to keep the patch watered during hot, dry spells while I’m in Brisbane? Our answer to this was to build wicking beds.
Wicking beds are raised beds that have a water reservoir below them. The reservoir is kept topped up and the soil and the plants access the water they need through capillary action. This method not only keeps the soil moist while I’m not there, it is also water efficient. As we are not on town water – relying on rain water tanks – saving water is very important.
These are the basic steps we took to build our beds:
- Level the ground (wasn’t easy on our steep block!)
- Build the wooden frame. Ours are made from pine sleepers.
- Add a layer of firmly packed brickies sand to provide a soft, level base.
- Line the bottom and sides with a sheet of thick black builder’s plastic.
- Install an overflow pipe where the top of the reservoir will be. This will allow any excess water to escape and ensure the beds aren’t waterlogged after heavy rain.
- Line the bottom with geotextile to help protect the plastic.
- Install the water delivery system. This is made up of a PVC pipe attached to the side of the bed with a PVC pipe T junction at the bottom. A loop of slotted agi pipe is attached to both sides of the T.
- Place a PVC flap valve over the top of the PVC pipe to help prevent mossies getting into the reservoir.
- Cover the bottom of the bed and the pipe with gravel to the top of the reservoir.
- Using the water delivery system, fill the reservoir with water (The reservoir is therefore made up of water sitting in gravel). Doing this now gives you the opportunity to check the gravel is level and at the same height as the overflow pipe. Also, at this point we left our bed to sit overnight to ensure there weren’t any leaks – better to know now than further down the track!
- Cover the gravel with a layer of geotextile. This prevents soil particles getting into the reservoir.
- Fill the bed with good quality soil. We incorporated lots of home-made compost full of big, fat health worms. They help aerate the soil and prevent it from going anaerobic.
- Enjoy planting out the bed and mulching!
- Water from the top for 5/6 days until the wicking process gets going.
More than two years on the beds and worms are still doing well.
We top-up the reservoirs each week. At that time, we also do a top water to help out surface roots. If planting seeds directly into the beds – such as for carrots, beetroot, top watering is still necessary until plants establish themselves.
Although we do now have other veggie beds, our 4 wicking beds are the most productive. Love ‘em!