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How to make a wicking garden bed

Let your clever garden water itself, from below!
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WATCH: Charlie Albone shows you how to build a wicking bed 

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Traditional raised garden beds can be great, but they may require large amounts of soil to refill as their levels drop when the soil breaks down. Wicking beds are a fantastic alternative that look similar but require less watering and far less soil.

This is because a wicking garden bed is designed with a water reservoir at the bottom, which feeds the plants above. This helps you save time and water. Plus, wicking beds are usually super simple to put together.

How does wicking work?

Wicking is the movement of water by ‘capillary action’, where water from a reservoir below the soil is drawn up and evenly distributed through the soil to the plants’ roots. Excess water goes through an overflow pipe, which ensures the soil doesn’t flood and doesn’t drown the roots.

Wicking bed in back yard
The final result! (Credit: Brent Wilson)
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Advantages of wicking garden beds

  • As water comes from below, there’s no surface water loss via evaporation.
  • Watering from above can cause fungal damage to foliage.
  • Roots that need the water get it, not the top bits.
  • A constant water supply means stronger, healthier roots – think of plump, tasty carrots and beetroot.
  • As the plant is always fully hydrated, leaves don’t get sunburnt during heat waves.
Wicking bed diagram

How to build a wicking garden bed

Gather your supplies

Here’s how to make a wicking bed

Step 1

Position your raised garden bed in full sun and on a level surface.

Step 2

Line bed with pond liner, ensuring there are no holes or gaps along edges and corners. Hold in position with bulldog clips.

Charlie Albone lining raised garden bed
(Credit: Brent Wilson)
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Step 3

Add 25mm of scoria to base of the bed.

Step 4

Coil agricultural (ag) pipe around scoria bed, with cap end sitting on rim of garden bed. Cover pipe with more scoria

Coil pipe in garden bed
(Credit: Brent Wilson)

Step 5

Drill 20mm hole into side of garden bed, just above scoria.

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Step 6

Install overflow tap parts in drilled hole and seal with silicone sealant.

Intsall overflow tap parts
(Credit: Brent Wilson)

Step 7

Trim liner to just above scoria.

Step 8

Cover scoria with geotextile fabric. Cut opening for ag pipe and trim fabric to fit.

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Cut opening for ag pipe
(Credit: Brent Wilson)

Step 9

Fill garden bed with quality potting mix.

Step 10

Plant seedlings, cover mix with sugar cane mulch and water well.

Step 11

After a couple of weeks when roots are established, fill pipe with water. Put cap on to prevent mosquitoes breeding.

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Plant seedlings
(Credit: Brent Wilson)

What are the disadvantages of wicking beds?

If you let the overflow water drain into the ground, you’re wasting water. If you let the overflow water drain into a bucket, empty it immediately into other parts of your garden or you’ll attract mosquitoes.

What do you fill a wicking bed with?

Line the base of a raised garden bed with pool liner then fill with scoria or pebbles – not  road base as there is too much fine material in it – into which you place an ag pipe, cover with geotextile fabric then fill with quality potting mix. The ag pipe protrudes through the potting mix as that’s where you add the water for the underground reservoir.

How deep do wicking beds need to be?

As deep as you like, but the soil/potting mix should be about 30cm deep.

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What is the best soil for wicking beds in Australia?

Only use quality potting mix. Soil needs microbial activity such as worms, beetles and beneficial organisms such as fungi and bacteria to keep it aerated. Without this underground activity the soil collapses and nothing will grow there.

Potting mix needs to replaced every couple of years as it breaks down and collapses too. You can toss old potting mix onto garden beds where it breaks down further.

Top 6 raised garden beds

01

Slimline garden bed

from $705, Kingspan

Best for: long-lasting and durable

This Kingspan slimline raised garden bed is made from food-grade polymer-coated steel that’s specifically designed for long-lasting, durable garden beds.

Key features:

  • Internal, food-grade liner
  • Suitable for growing herbs, fruit or vegetables
  • Five-year structural warranty

02

Gordo galvanised steel raised garden bed

from $69, Temple & Webster

Best for: narrow gardens

This stylish and practical garden bed is made from quality galvanised steel with an epoxy paint finish to help ensure longevity.

Key features:

  • Rounded and rubber-capped edges
  • Inward-facing screw reinforcements for durability and safety
  • 12-month product warranty

03

110cm Ergo Hex raised garden beds (set of 2)

from $219, Temple & Webster

Best for: design and architecture

This unique hexagonal design looks great and can also help you save space by fitting into corners or allowing for stackable beds.

Key features:

  • Ergonomic and space-saving design
  • Made from weather-resistant polypropylene plastic
  • Five-year warranty
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04

Potey raised garden bed with greenhouse

from $117.77, Amazon

Best for: protecting your vegies!

This galvanised raised garden bed also comes with a greenhouse frame and two covers so you can keep hungry animals away.

Key features:

  • Two greenhouse covers for different seasons
  • Soil ventilation holes
  • Designed for durability

05

VidaXL raised garden bed

from $76.99, Amazon

Best for: bad weather areas

This galvanised steel garden raised bed is weather-resistant and easy to assemble, so you could have flowers or other plants thriving in no time.

Key features:

  • Made from heavy-duty galvanised steel
  • Provides ample space for plants, vegetables, herbs and flowers
  • Open bottom design

06

Greenfingers round garden bed planter

from $57.95, Amazon

Best for: small, compact gardens

This round, galvanised steel garden bed is stylish, affordable and suitable for both small and large gardens.

Key features:

  • Made of quality galvanised steel
  • Latch design for easy assembly
  • 0.5mm thickness for extra stability

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