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Galvanized raised beds have become pretty ubiquitous when it comes to materials used for raised bed gardens. What probably started as a few clever green thumbs using stock tanks (large basins traditionally used to hydrate livestock) as gardens has evolved into a whole industry of garden containers and structures that mimic the design.
Aesthetically, raised beds made from galvanized steel add a modern, clean look to a garden. Practically, they will last much longer than wood, and can be placed absolutely anywhere that gets six to eight hours of sunshine a day (less if you’re growing shade veggies). Place one on the driveway, in the middle of the lawn, or on a small patio. Unless you opt for DIY, galvanized raised beds are perfect for those who don’t have the tools, woodworking skills, or time to build a raised bed. Simply set it up, fill with soil, and plant!
I love the look of both these instant and DIY gardens. I’ve gathered some tips and styles, so you can decide if you’d like to opt for a galvanized raised bed over one made of wood, fabric, plastic, etc.
Adding soil to galvanized raised beds
The soil mix you use for raised beds made from wood can be used to fill one made of galvanized steel. One thing to be mindful of, especially if you are looking to fill a traditional stock tank, is you need a LOT of soil. This can become pricey. A soil calculator can help you determine how much you will need based on your garden’s dimensions.
Personally, I have filled all my raised beds with a good-quality triple mix soil. This mix is generally one third soil, one third peat moss, and one third compost. I usually top-dress the soil with even more compost.
One question I get asked a lot in my talks is whether you need to change out the soil each year. The soil stays, but you’ll want to amend it with compost in the spring before you plant your veggies for the season. If for whatever reason you do want to change it out, see “false bottom fakery” below.
Using a stock tank as a raised bed
I love how many choices are available to gardeners who want to add that corrugated steel raised bed look to their garden. Stock tanks, as well as those round culvert pipes, are the original galvanized raised beds that have inspired a legion of styles, sizes, and heights that are manufactured specifically for gardening.
One benefit of certain traditional stock tanks is their height. For those who have trouble bending down or kneeling to weed and plant, the stock tank raises the garden up that much higher.
If you are turning a traditional stock tank into a garden, check to ensure there is a plug in the bottom. Remove it to create a drainage hole. If there isn’t a hole, you’ll need to create some with an HSS or HSCO drill bit (strong bits that are meant to go through steel).
Finding pre-made galvanized raised beds and kits
A lot of companies have cleverly created the look of a galvanized steel stock tank without the weight (stock tanks are heavy)—and often without the bottom, which you don’t really need. You can simply place the frame in a garden, on pavement or flagstone, or right on a lawn and fill with soil. Be mindful of the weight of your garden with the added soil if you’d like to place it anywhere else.
The best part is there are a lot of shapes and sizes available. If you have a tiny corner of sunlight, there is likely a galvanized raised bed that will fit. They also make nice additions around existing raised beds. Smaller ones can be used to grow plants you don’t want to spread throughout the rest of your garden, like mint or strawberries.
DIY options for corrugated steel raised beds
You can also use steel “sheets” to create a raised bed. When I started planning my projects for Raised Bed Revolution, I knew I wanted to include a wooden raised bed that included sides of galvanized steel (aka corrugated steel). I had the sheets pre-cut by a local company and simply screwed them to the wooden frame.
Use an HSS or HSCO drill bit to pre-drill your holes and then secure the steel to the wood with heavy-duty screws. Also, be sure to use thick work gloves when dealing with sheets—the sides are very sharp!
In my latest book, Gardening Your Front Yard, I experimented with using a galvanized steel window well to create a raised bed. For this project, I also pre-drilled holes to screw the window well to a length of wood I had measured out to the exact size I needed.
False bottom fakery
In my presentations, I like to share this tip from my gardening friend Paul Zammit. When he worked at the Toronto Botanical Garden, the public garden’s Veggie Village has several bottomless stock tanks with false “bottoms” for the soil.
Basically you just have to place large pots saved from plants upside down in the bottom. Cover with a layer of old wood, cut to length. Line the space that’s left with landscape fabric and use bull clips to keep the fabric in place. After the soil is added, remove the clips and tuck the edges of fabric into the soil. At the end of the season, you can easily send the soil to the compost pile, if you wish.
Are galvanized steel raised beds safe for growing food?
If you’re concerned about the process used to make galvanized steel, Epic Gardening has an informative article that explains why it’s safe to use these vessels as raised beds for gardening. I would recommend doing a bit of research on the manufacturer you’re looking to purchase from, as well. I used corrugated steel sheets from a local company called Conquest Steel for “Big Orange,” the raised bed I built for the Toronto Botanical Garden. These raised beds come with an assurance they are made with non-toxic materials that won’t leach into the soil.
Galvanized raised beds don’t just have to be for veggies
I’ve seen galvanized raised beds used for everything from privacy hedges to water gardens. Use them to organize different areas of the garden, or to delineate a little garden “room.”
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