Metal garden beds are a type of raised beds that are highly valued due to the various benefits they can bring to one’s garden. But there are concerns amongst some gardeners as to how long a metal garden bed will last, as well as whether it is worth buying one compared to all the other types of raised beds out there. I’ve done a lot of research on this topic and have written this blog post as a guide for anyone wondering how long a metal garden bed will last for their allotment.

Metal garden beds typically last at least 30 years, assuming that they are well-maintained. The biggest factor affecting the longevity of the metal garden bed is the type of soil that it comes into contact with regularly. Highly acidic soil can break down the zinc layer surrounding the metal garden bed which, over time, can decrease the lifespan of the bed itself.

As mentioned above, how long your metal garden bed is likely to last depends greatly on how acidic the environment surrounding it is. The biggest concern is the acidity of the soil, which should have great interest to anyone looking to buy a metal garden bed in the near future.

How Durable Are Metal Garden Beds?

Metal garden beds, otherwise known as galvanized steel garden beds, are a type of raised garden bed that are growing in popularity due to their ability to prevent weeds and maintain perfect soil quality.

Galvanized steel is a highly popular material and is used in various gardening products such as water storage containers, sheds, roofs, and more due to its durability. They’re also extremely easy to maintain and are long-lasting, assuming that you take steps to minimize the effects of zinc leaching (see below).

Because metal garden beds can be quite expensive, it is in the best interests of any gardener to make sure they get the most out of the lifespan of their purchase. And one of the key ways to do so is to understand what zinc leaching is and what impact it can have on your metal garden bed.

When your garden’s soil is too acidic, it can cause the layer of zinc that is coating the metal garden bed to start breaking down. While the breakdown process is relatively slow, over long time periods, it can lower the lifespan of your metal garden bed. And, the more acidic the soil is, the faster the breakdown.

This is why anyone seeking to use metal garden beds should first consider how acidic their soil is. Garden soils tend to range from pH-neutral to mildly acidic, and this can have an impact on the durability of your metal garden bed. It is recommended to use pH-neutral soil or to neutralize any acidic soil before using it with a metal garden bed. 

You may also want to consider using pH-neutral water for your plants. Natural sources of water, like taps or wells, may not be pH-neutral and can also contain other substances (like chloride or calcium) that can affect the acidity of the soil. Avoid using highly acidic sources of water or any water that has not been treated to neutralize the pH as this can speed up the breakdown of zinc from your metal garden bed. 

Also, keep in mind the preferred acidity levels of the plants in your garden. The biggest mistake a gardener can make is to assume that all of the plants he’s growing prefer pH-neutral soils.

While yes, it is true that many plants grow best in pH-neutral soil, there are some common exceptions including azaleas, camellias, and hydrangeas.  

Neutralizing all your soil and water in preparation for a metal garden bed can lead to an adverse effect on the growth of your acid-loving plants, so make sure you do the proper research beforehand.

Are Metal Garden Beds Safe?

Small amounts of zinc breakdown are inevitable and can actually be a good thing for your plants. Zinc is a normal component in most garden soils and an essential nutrient in both plants and humans. 

In other words, zinc breakdown from your metal garden bed is highly unlikely to harm your plants so long as it is minimized. Simply using pH-neutral waters and keeping track of the acidity of your soil is often enough in most cases.

You may be wondering if the breakdown of zinc is safe for consumption. This is particularly true if you are planning to grow foods for eating inside your metal garden beds (like vegetables). Again, the same principles apply here.

As long as some effort is made to prevent the excessive breakdown of zinc in your metal garden bed, there shouldn’t be any safety concerns related to eating the plants and vegetables you grow.

There are various ways to extend the longevity of your metal garden bed and ensure that it is safe to use. I’ll talk about this later on.

Can Metal Garden Beds Overheat?

Some gardeners are concerned as to whether metal garden beds can overheat during hot climates (i.e. during the summer). Because the metal is likely to be located in places with a ton of sunlight, there is a possibility that it overheats and transfers this heat to the soil, causing it to be overly dry and hence affecting the growth rate of your plants.

However, most gardeners who use metal garden beds regularly agree that your soil should not overheat so long as you maintain smart watering practices. While you may see higher temperatures from the soil near the edge of the metal garden bed, these are unlikely to be hot enough to kill your plants.

Those who water their plants consistently may find the warmer soil to be a beneficial thing for their plants as the water cools the soil, making it just warm enough to have a positive effect on the growth rate of your plants.

Remember, most plants love slightly warm soil and a metal garden bed can help facilitate this sort of environment.

How Can I Make My Metal Garden Bed Last Longer?

The zinc-coated steel that covers your metal garden bed is likely to last long enough to meet your long-term gardening goals. However, those of us on a budget may want to know if there is any way to squeeze that little more longevity out of our metal garden beds.

As mentioned previously, the most important thing to remember is to watch the acidity levels of the environment, particularly the soil. Some types of compost and manure are typically more acidic than others (like fresh chicken manure) and should be avoided.

Gardeners with a lot of acid-loving plants may want to reconsider using a metal garden bed or use liners like heavy plastic to prevent the acidic soil from coming into contact with the zinc lining. When doing this, avoid using plastic linings on the bottom of the bed as this can mess with the drainage.

Conclusion

Metal garden beds, or galvanized steel garden beds, are fantastic containers that every gardener should consider adding to their repertoire of tools.

When set up correctly, metal garden beds of a certain height can save a lot of bending over in the garden. They can also prevent the growth of weeds, drain water effectively, and help maintain the quality of your soil for long periods of time.

The best part is, the average metal garden bed is likely to last at least 30 years, more than enough for any long-term gardening goals. But care must be taken to prevent the excessive breakdown of zinc that is typically caused by using soil that is too acidic.

If the right steps are taken to minimize the effects of zinc leaching, a metal garden bed can turn out to be one of your longest-lasting purchases when it comes to gardening tools.