By Steven Biggs
Make Your Own Wicking Bed
Harvest more. Water less.
Wicking beds are a great way to maximize the use of space in a small garden. They also save time for busy gardeners.
What’s a Wicking Bed?
A wicking bed is simply raised bed with a reservoir—a water storage area—at the bottom.
They work the same way that sub-irrigation planters (a.k.a. SIPS or “self-watering” pots) work.
Water wicks upwards from a reservoir below into the soil above through capillary action.
Find out more about sub-irrigated planters.
Less Plant Stress
When plants get thirsty—when there is “water stress”—it can have a big effect on yield.
Because wicking beds prevent water stress, the increase in yield can be considerable. Of course, no one minds the time saved by having to water less frequently.
Even in the heat of summer, when the tomato plants are quite big, we water our wicking beds about once a week.
We turbo-charged our backyard tomato production using wicking beds.
Another Reason to Use a Wicking Bed
Our neighbour’s large black walnut tree is beautiful. But walnut trees give off a compound called “juglone.” And juglone affects the growth of many plants…including tomatoes.
We tried growing tomatoes in the backyard many times…and they always died.
BUT MY DAUGHTER Emma had a vision of a tomato plantation in our backyard, near that walnut tree.
I wondered if we could solve the problem by growing in wicking beds, because the tomato roots would never get into the juglone-contaminated soil below.
It worked—and we now grow tomatoes right under the walnut tree.
Make Your Own Wicking Bed
Be creative with the materials you choose. We decided to use cedar fence posts to make our wicking beds.
Below are photos of wicking beds that I made with my kids using cedar fence posts.
I chose cedar fence posts because they are long-lasting and not much more expensive than dimensional lumber.
Beds made with dimensional lumber often sag outwards over time...and I’m not interested in rebuilding my wicking beds any time soon.
I chose pond liner to create the reservoir because I already had pond liner here.
Be Creative
Be creative! You might want to make a wicking bed from salvaged material—or maybe you want a bed that ties in with the aesthetic in your landscape.
On the practical side, I’ve see wicking beds made from large plastic bins and from recycled lumber.
On the ornamental side, I think red brick would look smashing! One day…
Here’s an Idea
Convert a metal raised bed into a wicking bed!
I really like these metal raised beds from Sproutbox Garden. The owners of this Canadian company have offered a 10% discount for my readers.
Use this code to save 10%: foodgardenlife.
Materials List for My Wicking Bed
Cedar fence posts.
Pond liner. The pond liner holds water in the bottom of the bed. Once the sides of the liner are bent upwards and fixed into place, it creates a shallow water storage area at the bottom of the bed--about as high as the weeping tile.
Weeping tile.
3/4” gravel. Use “clear” gravel, which means that it does not have smaller pieces of gravel that will fill up the spaces in between. That way the space is available to hold water.
Dishwasher drain tube. To create a fill tube.
Landscape fabric. Its purpose is to keep the soil from filling up the piping and the spaces between gravel.
Steps for Making a Wicking Bed
Cut posts to length and notch the ends.
Place notched posts directly on the ground. Level the ground first.
Nail spikes into the corners of the posts to keep them in place.
Install liner at the bottom by placing it on the ground, and up about 8-10 inches at the side. Secure temporarily with staples, to keep it in place until the gravel pins it into place.
Place coils of weeping tile in the bottom. The tile permits water to quickly move through the reservoir, and it also holds up the soil above.
Add gravel. It supports the weight of the soil above, while the spaces between the pieces of gravel fill with water. Water moves upwards through the gravel by capillary action.
Note the fill tube at the far end, a piece of drain hose installed into the weeping tile. This permits filling of the reservoir with a hose after soil has been added.
Cover with landscape fabric to keep soil out of the reservoir area. Note the depressing in the top-right corner: While in theory water wicks up the gravel, I also created this soil-filled wick that dips into the reservoir.
Approximately one foot of soil works well. If there is too much soil, the water will not wick all the way to the top.
Watering my Wicking Beds
I know that there is enough water in the bed as I'm filling it because once the storage area is full of water, I see water coming out of the side of the bed. It's low-tech—but it works.
One More Reason for Wicking Beds
Soil contamination is another reason to consider growing in a wicking bed. Soil contamination can be a concern in areas where there is a history of industry, and also on former orchard lands where sprays with heavy metals might have been used.
Find out more about soil contamination and what to do about it.
Another Way to Add Growing Space in a Small Garden
Straw-bale gardening is a great way to grow on paved areas and areas with poor soil.
Find out more about straw-bale gardening.