One-Metre Square Wicking Bed - Build or Buy?

I'm thinking about installing planters with extra water storage on the north-facing lawn. There is space for 3 to 4 planters of 1 metre-square.  To buy similar planters would be about $1500  - $2000 ballpark. I wondered if I 'could build my own for significantly cheaper, so I built a prototype

Wicking beds are a common technique used by gardeners, preppers, homesteaders etc to provide a larger scale raised planter with onboard water storage. 

In this post, I review my experiment at building a 1-metre square wicking bed, the various considerations for 'build' or 'buy', and what I think is is best for my situation. 

The format is first a synopsis and then some light additional detail.

Synopsis  

I converted an IBC tote into a wicking bed. (see 'What I Built' below).  Being an experiment, I tried to cut costs by using existing materials on hand, which ended up causing more work for myself. I took the approach of a 'hollow centre' (see 'Reference Guides' below).

Results From This Experiment

The final result produced good crops, though it looks like my construction method caused uneven wicking. I intended it for crops with shallow roots e.g. lettuce, but discovered it handled deeper rooting crops well e.g. carrots. 

Water-storage was as hoped for, with no top-ups from early October to late November.

This experiment also taught me 

• I want the beds to be portable, either around the property or to take to my next place. 
• Most methods involve plastic and/or artificial matting, which I want to minimise.
• Onboard water was useful but not essential.

Build Versus Buy?

An important lesson was the value of buying versus build-you-own (see the comparison section below).  In my opinion, converting an IBC tote yourself is for people   

• Who are confident taking on simple construction jobs and power-tools
• Who are ok with a semi-permanent installation.
• Are considering getting more than one bed. One tote can provide the container for two beds.

If you are going to teach yourself, then I suggest copying a proven template and accept the costs involved of doing it right. Doing my experiment on the cheap, using existing materials, forced me to improvise  and caused a lot more fussing around.

If I was starting from scratch again, and just wanted one or two beds, I would buy an off-the-shelf option, as 

• There is a lot less effort, learning and skills involved. 
• The price difference is worth the setup effort saved 
• The right option would be easier to move in the future.
• No need for basic power-tools (cutting and drilling) and related safety-gear.
• Water can be stored via a rainwater capture system, and the watering itself automated with an irrigation timer/system.

What About The Long-term?

With space for another two or three beds, I'm leaning towards building these as all the hard learning and mistakes have been done. However, now that I know what's involved, my first priority is to make best use of existing growing space.

Thanks for reading and I hope you got something out of this :) The 'additional detail' follows below.

Additional Detail

What Did I Build?

Key features:

• The bottom half is the water reservoir, with the top-half flipped over and reinserted as the base for the soil. To prevent algae forming in the water, the reservoir is wrapped in black plastic.  
• This top-half rests on several plastic buckets, creating space for the water.
• The single wick is sterilised sand inside an improvised sock. 
• This feeds up into a layer of sterilised sand used to distribute the water across the base surface. A layer of mulch cloth separates the sand from the potting mix which is the final layer.
• The soil is about 250 mm of potting mix with additional amendments. 
• There is a inlet to add water directly into the reservoir and an outlet to prevent flooding.

Reference Guides

The various wicking beds I saw on YouTube fell into two categories

a. With a 'hollow centre' water reservoir e.g. https://www.youtube.com/watch?v=InQW7838HrM

 

b. With a porous reservoir: https://www.youtube.com/watch?v=obNWr8MD0uU

Comparison of Options

This is the information I used to compare 'build your own' versus 'buy off the shelf' options. I compare what I built against the equivalent size Vegepod product. A notes on cost figures used: 

• Home-made option: Most of the materials were already on hand and I have given them an estimated price to enable more realistic comparison.
• Vegepod option:  Prices as per Bunnings RRP as of 16/12/23.

	Home-made	Vegepod (1 m x 1m)
Base	$223 (IBC tote, plastic wrapping etc)	$359
Fill	Sterilised Sand and potting mix - $90	210 Litres of potting mix = 7 bags of 30L @ $16.97 = $118.79
Wood For Flat base	$20	$20
Total	$333	$474 (+ $141)
Time to Prepare container	~ 12 hours (assuming no water hookup)	Approx 1 hour (assuming no water hookup)
Unique points:	Est. 150 litres water stored on board/ Watering time and attention saved. Harder option to relocate - has to be completely disassembled and reassembled.    No reliance on custom parts.	Less water storage / drought resiliance / more attention required.  Easier to relocate. Dependence on custom parts if something breaks