Hands in the Dirt: Steel Garden Beds

Story and photos by Donna Iverson

When it comes to raised garden beds, I'm a traditionalist so prefer untreated wood to grow my veggies in.

The community garden where I grow my veggies is transitioning to galvanized steel metal beds and I'm not happy about it. But I am in the minority.

These steel metal raised beds are becoming increasingly popular with home gardeners, community gardeners, cities and towns and local businesses. With good reason.

First, they can bring plants to inaccessible places like decks, patios and even along a town's main thoroughfare in front of local businesses. During the holidays, you can easily decorate them with evergreens and red ribbons.

A metal bed is cheaper than a wood one, lasts longer, and you can start the gardening season earlier, as it retains the heat of the sun. It is less likely than a wood bed to be infected with pests. These beds come in all shapes and sizes, are durable, portable, and have a contemporary look.   But there is a downside.

In an effort to convince my fellow gardeners to stick with wood raised beds, I began researching the negatives.

Mostly my objection was aesthetic, as they look like cattle watering troughs to me ....which they are. But that didn't convince the gardening committee, whose members just shrugged when I brought up aesthetics. Beauty is in the eye of the beholder, commented one member.  Plus they are cheap and last longer, said another.   

But you have to water them more often as they dry out more quickly, I countered.  Another group of shrugs. Tomatoes will love them, came one retort.

Clearly I needed a stronger argument. Was there a food safety issue? Maybe.

Galvanized steel is made by coating the outside with zinc. Zinc will leach out of these metal containers as they age or are exposed to acid soil. So best not to grow acid loving plants, like blueberries, in them. Too much zinc in your diet is toxic.

But the research on the effects of galvanized steel on growing vegetables is sparse and inconclusive. Seems like zinc will leach into the soil as the years go by but not enough to really cause harm, research claims. Still, I'm not taking a chance, I told the garden committee.

That's when I learned that my rotting wooden bed was scheduled to be replaced in the spring with one of the galvanized steel ones, as were all the remaining falling-apart wooden beds in the garden.

Will let you know in 2020 whether or not I can live with this.