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. Here, landscape designer Charlie Albone walks us through the process of making your very own wicking garden beds with step-by-step pictures.
How to build a wicking bed
Gather your supplies
- Raised garden bed with base (We used this one from Kingspan.)
- PVC pond liner
- Scoria
- Slotted agricultural pipe with end coupling and cap
- Overflow tap, male and female parts
- Silicone sealant
- Geotextile fabric
- Potting mix
- Vegie seedlings
- Sugar cane mulch
- Bulldog clips
- Electric drill
- 20mm hole drill bit
- Caulking gun
- Utility knife
How to make a wicking garden 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.
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
Step 5
Drill 20mm hole into side of garden bed, just above the scoria.
Step 6
Install overflow tap parts in drilled hole and seal with silicone sealant.
Step 7
Trim PVC pond liner to just above the scoria.
Step 8
Cover scoria with geotextile fabric. Cut opening for ag pipe and trim fabric to fit.
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.
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.
Advantages of a wicking bed
- 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.
What are the disadvantages of wicking beds?
One of the disadvantages of a wicking garden bed is managing periods of excess water. This is where the overflow tap comes in handy, but if you let the overflow water drain into the ground, you’re wasting water. If you let the overflow water drain into a bucket and empty it immediately into other parts of your garden or you could attract mosquitoes. Setting up the wicking bed correctly in the first place is paramount to its success, so avoid making these common wicking garden bed mistakes.
What do you fill a wicking bed with?
Line the base of a raised garden bed with a PVC pond 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.
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.
Shop 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
04
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
05
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
