Cost Effective Plastic-tub Wicking Beds





Introduction: Cost Effective Plastic-tub Wicking Beds

Yay, finally my first instructable.

In this project, I will just go into one of my projects to create more growing space in suburbia of Aussie cities. With the ever decreasing property block sizes, subdivision etc., gardening space is diminishing, so there is a need to think outside the box.

Wicking beds aren't anything new, so I won't go into the principles of them.

Here's an excerpt from the Seed Savers Albury-Wodonga organisation (

"The concept of wicking beds is similar to the way self-watering pots work. They are built to include a reservoir of water below the soil. The ‘wicking’ part refers to the soil and plants being kept moist as the water ‘wicks’ from the reservoir into the soil. An overflow ensures that the bed doesn’t flood. Instead of watering onto the soil above the plant roots, as we usually tend to do, in a wicking bed, you instead fill the water reservoir using a dedicated inlet. When the reservoir is full, any excess water is released via an overflow.

Some advantages of wicking beds, particularly for our summers, are that they allow for constant soil moisture without becoming waterlogged. Wicking beds require less frequent ‘watering’ (refilling), so they are great for those who go away, for workplaces and just to avoid the need to water every day in summer or risk losing your plants. As the water is stored below the soil, it is possible to mulch the top of wicking beds heavily, which further helps to reduce evaporation from the soil and can help keep the soil cooler too. They do take more time, materials and effort to build, and there are some maintenance considerations for wicking beds.

As with any garden approach or tool, it’s important to ensure wicking beds are a suitable match for the type of garden and plant choices you have in mind."

Step 1: Acquire the Materials

I found 50 litre tubs were ideal for an area at the back of my place that gets full sun.

Here's a list of the materials that I used. Most I already had from previous projects, but I'll try to at least give you an indicator or the individual cost and bulk cost.

The total cost of each tub ended up being $14.02.

Yes, there is also the cost of soil and mulch, but this will vary depending on your preference.

I use organic garden soil which is $57 / cubic metre, but I found for 7 tubs, I only needed quarter of a cube, which ends up being $2.04 per tub

For the mulch, I used Sweet Garden Organic Sugar Cane Mulch being $14.90, but per tub the cost is $0.21

So, the revised total with soil and mulch ended up being $16.27 per tub.

Step 2: Creating the Reservior

Now you need to create the reservoir from which the soil and plants will wick the water from.

It's really easy. Just snake the drainage pipe so it's snug in the tub. I found using zip or cable ties at each end of the pipe helps keep the sock in place and prevent it from retracting.

Once you've laid the pipe, just pour the blue metal in the gaps which will help to keep the pipe in place. Just fill is to the top of the pipe and don't cover.

Step 3: Create Holes for the Re-fill and Overflow Pipes

On one side of the pipe, cut a hole for the re-fill pipe and on the other side, another hole for the overflow pipe. This can just be done with a pair of scissors.

You will need to drill a hole in the side of the tub where the overflow pipe will be coming out of.

The top of the re-fill pipe will sit above the soil and mulch level, so no modification to the tub required here.

Step 4: Lay the Weed Mat Over the Reservoir

Finally cut the weed mat to size.

It doesn't have to be perfect, but do your best to cover up as much of the reservoir to prevent your soil falling into it.

Step 5: You Won't Be Able to Stop at One

So that's it.

I ended up making 7 in total and planted things such as chillis, tomatoes, strawberries, lettuce, zucchini, spring onions, get the idea.

I'm still in the process of researching what else I can plant, but my aim is to use these for plants with a shallow root base so as to not use up precious real estate in my larger, deeper garden bed which I can use for plants which require deeper roots.

Enjoy and let me know if you end up creating your own.

Step 6: Update to the Plastic-tub Garden

So, this addition was always in the pipeline, but with a particularly warm day wilting a few lettuce seedlings, I brought it up the timeline.

I purchased some garden stakes to create a bit of a skeleton structure around and over the beds. Once that was completed, I just measured and cut shade-cloth to size and then just zip-tied it to the structure. As you can see in the photo, I can have the shade-cloth covering both the top and front side, or roll it up and just have it on the top.

Hopefully this will not only reduce the suns rays wilting any plants, but prolong the life of the plastic tubs from the UV rays...many thanks to all who have already made comments and constructive criticism regarding UV vs plastic.



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How well does the plastic hold up against UV. I tried planting in small plastic storage tubs earlier this season and the plastic turned very brittle and started falling apart after a few months.

I'll let ya know after the Spring/Summer season goes...the consensus throughout earlier comments is that this is bound to happen...just a matter of seeing how long it takes

Hi...I see that folks are commenting about substituting the plastic bins for pallets. I'm posting this link regarding how to determine if a pallet is safe to use for projects.

Thanks for the link...will definitely have to have a read of it.

The main purpose of using the pallet wood is that it should be readily accesible and most of the time free.

Once you'd build a garden box out of it, you'd still line it with thick black pond lining so you can still have the reservoir of water at the bottom.

Hope this helps.

A fabulous idea, and one I will seriously think about. One way to protect against the uv light would be to paint or otherwise cover the sides of the plastic tubs but checking costings you might find it cheaper to just replace the tubs when needed. If you are serious about growing more food items check out the book 'Square foot gardening', there is a website which will explain the principles. I got a copy from the library and photocopied the relevant pages. I have been able to keep a family of 4 adults supplied with minimal water usage although the wicking would help there. Well worth a look, can easily be modified to suit different needs but can grow deeper rooted items like carrots etc. as well in tubs and the like. Not a problem in Australia I know but a word of warning for those in other climes, a wet summer (and we've had a run of those lately here in Ireland, family in NZ say the same there too, although they say it saves on the irrigation) and the vegetables will rot in the ground. The last few years I've lost everything, even with lots of holes to allow the water to escape. Will try your idea though and add a plexiglass roof over them, I'd rather irrigate than risk the flooding which I've suffered recently. Many thanks, I'd never though of using these boxes before but it makes perfect sense.

i dont understand the purpose of the weed mats below the soil. is it just to separate the soil from the gravel? if so then some of those cotton hand towels that are sold in bulk would be cheaper to use. i checked the prices of weed mats and they are very expensive.

Sure you could use any porous material. I don't know which weed mat you may have seen. I've included the costing of what I bought and I think it's pretty cheap. Regardless, the whole purpose of the barrier is to ensure the soil (organic material) doesn't sit in water and develop bad smells and other stuff...I'm not big on the sciency stuff, but everywhere else I've see wicking beds, there's been some sort of a barrier. Hope this helps.

The barrier also keeps the roots of plants from dropping into the wet zone those allowing too much moisture uptake. It also makes for easier clean up when you get too much moss or other material on rocks or want to replace the soil - not things you would do often but making them easier to do when the time comes.