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Make a Wicking Barrel Self Watering Garden Bed

Wicking Barrels or Wicking Beds are a Great Way to Garden

A wicking barrel or wicking bed is a great way to garden in both a water and nutrient efficient and responsible way. The basic idea is that the bottom of the bed contains a reservoir where watar is held until needed by the plants. As plants in the bed transpire through their leaves, they suck moisture from the soil. This creates a wicking effect as water moves up through the soil to replace that which was lost, all a result of water’s surface tension properties. The actual soil itself loses little water to evaporation (especially if you mulch well) and so the result is a productive garden bed that uses less water than any conventional bed could ever hope to achieve.

Wicking barrel

In this article I will show you how to make a simple wicking barrel or wicking bed. If at any time you are having trouble following along with the written word, make sure to watch the video below where I demonstrate the construction process. This is a design I got from Rob of Bits out the Back and I much prefer it to the old gravel reservoir, weed mat and compost sandwich that is the traditional wicking bed.


> Barrel – I prefer to use a 44 gallon drum (in reality about 45 gallons, 205L) but you can use any barrel made out of a food grade plastic. Be sure that you know what was in it before you use it to grow food!
> 19mm tophat grommet
> 19mm straight barbed connector irrigation fitting
> 1.5m(ish) of socked slotted Ag pipe
> 50cm of 30mm pvc pipe and a 30mm blank end cap
> Small square of shadecloth or flyscreen
> Zip ties


> 22mm hole saw
> Drill
> Jigsaw
> Hobby knife
> Marker pen
> Tape measure

Making the Wicking Barrel

1. Mark a line at the half way point on the barrel. You can use a straight piece of cardboard to help you connect the measure marks get a line all the way around the middle of your barrel.
2. Use a jigsaw to cut the barrel in half. There are various ways to start the cut. You can angle into it using the jigsaw, but easier is to drill a start hole or start the cut with an angle grinder.
3. Clean up the cut edges using the hobby knife.
4. Drill a drain hole using the 22mm hole saw. The drain height will depend on your barrel and the ag pipe used. Ideally you want to have at least 300mm of soil above the drain pipe and you want the entire ag pipe reservoir to be below the drain. Clean the hole up using the hobby knife to ensure a good seal with the drain grommet.
5. Wrap one end of the straight barbed fitting with the shade cloth and zip tie this in place. This will prevent media from leaving your wicking bed through the drain hole. Cut off the excess zip tie tail.
6. Place the tophat grommet through the barrel’s drain hole from the inside to the outside. Then push the not covered barb of the drain fitting through the tophat grommet. Push it until you feel it pop into place (you will know what I mean when you do it).
7. The Barrel is now complete. Now tie the sock on one end of the ag pipe and place it in the reservoir.
8. At the other end cut a small opening for your filler pipe in the top side of the ag pipe. Place the filler pipe in the ag pipe and pull the sock up over the end of the ag pipe and around the filler pipe. Zip tie the sock in place.
Drill a two holes through the top of the barrel and through the filler pipe so that you can zip tie it in place. This stops little hands (or paws/mouths) from pulling out your filler pipe. A massive mess I would NOT want to deal with.
9. Sit back and admire your work! You have just built your first wicking barrel.

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