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The benefits of a self watering raised bed have become clear after a summer of constant daily watering due to drought. Building one now ranks high on my project list. I’d seen manufactured self watering pots with their water reservoirs on a much smaller scale. But it was my research for Raised Bed Revolution that introduced me to a gardener who had an entire rooftop garden filled with what she referred to as SIPs—sub-irrigated planters.
Since then, I’ve discovered both innovative pre-fabricated planters and kits, and clever DIY options. I thought I would share some of them here, as well as the benefits, in case you want to add one to your collection of raised beds and planters, or if you’re a first timer who is keen to test out their green thumb. Personally, I love the idea of less watering!
The benefits of a self watering raised bed
Just like growing in regular raised beds, self watering setups have a multitude of benefits—and some added advantages.
- Water less often!
- You can comfortably leave your garden for a few days without having to ask someone to water for you—or risk losing plants if it’s not watered at all.
- You control the soil. This is a great option for those who have issues with hard-packed, clay, or contaminated soil.
- A self watering raised bed can be placed anywhere. You don’t need a typical yard. Position it on a patio, deck, balcony—even on a rooftop (after making sure everything is structurally sound with the weight, of course).
- More consistent watering means less chance of plants developing issues, like blossom end rot.
- You’re not dragging your hoses or lugging heavy watering cans around every day.
- If you’re on a balcony or rooftop, you don’t get the runoff that occurs after regular watering.
- Watering plants from underneath can help prevent fungus and disease because you’re not getting the splash-back from the leaves.
- Not watering from above also helps prevent flower and leaf damage from droplets.
How does a self watering raised bed work?
Essentially, no matter the size, whether it’s a smaller pot or a large raised bed, an oxygen water chamber sits below the soil. Capillary action wicks water up through the soil. Plant roots receive and benefit from both the water and the oxygen.
A fill tube connected to the reservoir allows you to replenish the water supply when it’s low. Pre-fabricated containers will have indicators showing when you need to add water. For DIY systems, you’ll need to check the soil to determine if there is moisture coming up from underneath.
Kits and pre-fabricated planters
There are a lot of really great self watering raised bed planters, both pre-constructed, and available as kits. I think Lechuza‘s smaller self watering pots were among the first that I learned about through my garden writing, though I see they now carry bigger containers for multiple plants.
In 2016 I had the pleasure of meeting Paula Douer of Crescent Garden at an event and learned about their TruDrop self watering system. It’s what makes The Nest, which I saw in person at the IGC Show in Chicago in 2018, a great option for balcony gardeners—or even for indoor gardening (in the latter, there is a plug for the overflow hole). The reservoir is large enough that you only have to water every two to six weeks.
When I set up a raised bed area at Canada Blooms a few years ago with projects from my book, I included a vegepod, a kit that was super-easy to set up. Not only is it a self watering planter, there is a “lid” that provides frost protection to extend your season. Niki has written about growing veggies in vegepods, too.
Building your own self watering raised bed
If you want to go the DIY route, there are a few different options. You can easily scale the size of your raised beds based on the space available and your materials.
The gardener whom I mention above with the rooftop garden is Johanne Daoust. I visited her garden while I was writing Raised Bed Revolution. It was the end of the growing season, so I was able to get a closer look at her SIPs than I would have in the middle of the season when everything was all lush and full. Daoust has spent a lot of time researching and experimenting with different setups. She even teaches about it. In 2015 she won a Green Roofs for Healthy Cities award in New York.
Daoust creates her raised beds in plastic tubs and pots. She lines them with plastic and puts the oxygen reservoir at the bottom. She uses perforated pipe covered in a nylon stocking and adds a fill tube (she’s used stacked water bottles).
Her raised beds sit on two inches of blue insulation Styrofoam to protect the rooftop. Daoust spends a lot of time ensuring her beds are level.
Building wicking beds
Food gardening expert Steven Biggs was inspired by Australian Colin Austin’s wicking beds when he built his larger-scale self watering raised beds from scratch.
What motivated his construction was the giant black walnut tree in the neighbour’s backyard. (Of course he soon realized how amazing the self watering feature is, too.) Because of the juglone present in the roots, the Biggs can’t use about half of their property to grow food. Straw bale gardening proved futile, as did a regular raised bed lined with landscape fabric. And so Biggs went the wicking beds route, using cedar fence posts to build the outside.
Biggs recommends a raised bed that is no higher than 12 to 16 inches.
“It’s unbelievable how well the plants do,” says Biggs. “There’s no water stress—I think that’s a huge part of it.” The wicking bed created the perfect conditions for Biggs’ daughter Emma, with whom he co-wrote Gardening With Emma, to grow her tomatoes.
For more raised bed inspiration…
- Raised bed designs for gardening
- Elevated raised bed gardening
- Preparing a raised bed garden
- Turn an old washbasin into a raised bed
- Build a DIY cold frame out of an old window