Raised beds are growing in popularity. By using raised soil, you can have perfect soil quality. Weeds are easier to prevent and a good quality lifting bed can last a long time. Many are made of wood, others of brick or rock. But galvanized steel is also becoming a popular choice, which raises a rather important question:Is galvanized steel Garden Bed safe?The following content also has some reference value for raised garden beds.
The short answer is yes, they are perfectly safe for gardening. Because it requires acidity to break down the zinc coating of galvanized steel, and most garden soils are neutral, there is little effect. In addition, zinc is an essential plant micronutrient and a normal part of soil. We'll talk about all of this in more detail later!
We love metal beds so much that they were the first product we chose to launch in our online store. There are a variety of options available and we think you'll love these high quality galvanized garden beds.
Our favorite galvanized bed:
What is galvanized steel?
Galvanizing is the process of bonding a layer of zinc to the surface of a ferrous metal such as steel or iron. This process prevents steel or iron from rusting when exposed to moisture.
Most galvanized steel is made by hot dipping process. Steel plates, whether corrugated or smooth, will be completely submerged in molten zinc. This forms a uniform layer on the surface of the steel. Sometimes, the metal is cooled so that the material is fully bonded, and then re-impregnated for a secondary coating.
Not all galvanized steel is coated with pure zinc. Some galvanized metals are treated with alloys. For example, aluminum zinc is an aluminum and zinc coating commonly used in hot dip galvanizing. The aluminum forms an outer layer that protects the inner layers of zinc and steel from moisture.
What is the use of galvanized steel?
A better question is what galvanized steel is not being used for. Galvanized steel is the preferred material for livestock troughs, the exterior of grain silos and water storage containers, shed construction, roofing, gutters and downspouts, and a number of other products. It is sometimes used as a durable fence board.
For decades, galvanized steel pipes were also the standard for domestic plumbing. Although galvanized pipes have now been replaced by PVC and copper, most older homes still use galvanized fittings. As long as the zinc coating remains intact, the pipes will continue to be used for years.
In food use, galvanized metal is rarely used for cooking and is more commonly used for storage containers. When zinc is heated to high temperatures, it releases gas into the food and the surrounding air. This makes it unsuitable for cooking containers. However, containers made of galvanized steel are perfect for storing things!
Does zinc leach from galvanized metal?
Yes and no. If you have extremely acidic water, such as acidified water in a well, that has not been treated to neutralize the pH, the zinc will gradually break down. If the coating is thick, the process can take decades. Most urban water sources neutralize the pH of the water through their facilities, meaning it is unlikely to be a major problem.
In fact, zinc is a normal ingredient in most soils. Both plants and humans need small amounts of zinc to survive. You'll also find it in your daily multivitamins! Plants need less zinc than we do, but it's still needed. The trace amounts they absorb from your bed are not harmful to the food you grow, nor should they be harmful to the plants themselves.
Zinc itself may not be harmful to human or plant health, but impurities in zinc may be. Concerns have been raised about lead contamination in zinc. This has led manufacturers to take steps to reduce the risk of lead contamination by using only pure zinc or aluminum-zinc alloys. You are less likely to find problems with lead from galvanized containers than you are to find it naturally in your soil.
So yes, acidic conditions may cause some zinc leaching. But zinc levels are extremely low, and some plants may prefer trace amounts of zinc in the soil. As long as the steel comes from a reliable manufacturer, there's no need to worry about your bed leaching toxins.
Is aluminum leached from galvanized metal?
While one can never say never, there is no significant risk of aluminum-zinc-galvanized aluminum leaching into the environment. Aluminum used for aluminum-zinc galvanizing is lighter than zinc when molten and rises to the outer surface during hot dipping to provide an ultra-thin protective coating for zinc. This protective coating prevents the loss of soluble zinc if there is any additional coating such as paint, this can even add another layer of protection to the aluminum surface.
Aluminum itself is much less soluble than zinc, which is why it has long been used for food storage. In addition, it is resistant to acidic conditions, which is an important point to note when used with soluble zinc. Without aluminum linings for canned food and aluminum cans for drinks, we wouldn't have most of the long-term food storage options we currently have! There were concerns about the safety of aluminum cookware as far back as the 1960s and 1970s, but intensive research has determined that even aluminum cookware poses no risk to humans. Because your garden bed will never reach a few hundred degrees of heat and cookware even in direct sunlight, the very limited amount of aluminum in the aluminum-zinc coating is completely safe and protects the zinc from degradation.
Can galvanized steel be used for overhead beds?
Absolutely! Galvanized metal raised beds are becoming the most popular garden beds. They are durable, strong, resistant to damage, will not rot like wood, and will last for decades. Plus, they look great and can evoke a ranch or industrial atmosphere. Galvanized POTS don't expand or contract, don't need to be oiled or painted to maintain it (though you certainly can if you want to), and can take whatever nature throws at it.
The shallower lifting bed is easy to fill with your preferred pH neutral, well-drained soil of choice. However, deeper formations may require more filling material. We have a great article on how to fill a tall metal garden bed that goes into more depth on this topic!
Can a metal-raised garden bed be too hot?
Not at all! It is true that most metals heat up in the sun. But moist soil is a fantastic coolant for hot metals. In general, your garden or pot won't get too hot, especially if you keep watering it.
Because the metal can conduct some heat, the soil immediately on either side of the raised bed may be warmer than the center of the bed. This can actually be a beneficial thing, especially in the spring. Raised soil warms up faster than the ground, which allows you to start growing vegetables earlier. Your seedlings will love warm soil at the roots!
In mild climates, a metal raised garden bed can help you maintain a more stable soil temperature throughout the year, provide good drainage for excess water and more. The hard, sturdy material will provide a good cold frame base for your wintering plants. These beds hold moisture well when using an absorbent hose.
Raised garden bed option
Choosing a commercial galvanized garden bed can be complicated. There are a surprising number of options on the market, from large vegetable gardens to basic planters.
I really like the beds designed by Australian manufacturer Birdies. These sturdy galvanized beds are very effective. They are galvanized with aluminum-zinc, a material made up of 55 percent aluminum and 43.4 percent zinc with a small amount of silicon. Each container is designed with practicality in mind. Some even offer multiple configurations that let you choose the exact size and shape you need!
Those of us with limited growing space might be interested in their galvanized POTS and flowerpots. The Courtyard - Balcony - Deck line (CBD for short) is a fantastic product line. Instead of using corrugated metal, they opt for a smooth, sleek and streamlined design that fits seamlessly onto porches and patios.
But if you have a lot of space in your garden, fear not! Their original product is perfect for you. Both 15 "and 30" depths are available. These beds offer plenty of square feet and can be configured into your space. I prefer their long, narrow configuration (which works out to be about 5.25 'x 2 '). But you can also choose squares or rectangles of other widths. It's perfect for a vegetable that you can use for decades.
Do you have a place for only one round bed? The tall, circular bed provides the perfect habitat for your potato plants, and its depth allows you to continually add soil and expand your potato production. You can make an eye-catching salad garden by filling it with concentric circles of lettuce, or make an herbal display. The options are endless!
DIY Build: Raised galvanized steel garden bed
If you have galvanized sheets, you may want to consider building your own DIY bed. Make sure you have a good galvanized steel, which means roof or other exposed elements. You'll also need wooden corner posts to hold the steel in place, and some corner flash to protect the edges from fraying.
There are many designs for this style of bed online, and a quick search will bring up a list of patterns and materials you can use. We also have a few models in our list of over 50 raised beds! However, one thing I recommend is to reinforce the sides of deeper beds with galvanized pipes. A short pipe is knocked into the soil on the outside of the bed to prevent the steel from bending outward as it is filled.
One thing to consider with these DIY beds is that they require wood as well as metal. This wood has a shorter life than galvanized steel, so you may eventually need to replace corner posts and other wood used in construction. If you paint the outside of the post first, you may extend its life, but be careful to choose a paint that won't leach chemicals into the soil.
Also, steel plates can have sharp edges, so you want to prevent potential injury. It is necessary to create a top cover to cover the exposed edges of the steel. You can create a bench like surface by attaching a 6 "or 8" wide board to the top of the bed and screwing it into the corner posts. This will also hide the open end of your rebar pipe.
Secure the metal raised bed
Galvanized steel is something sturdy that will stick to most garden uses. But there are ways to make sure your containers are safe for decades to come!
Avoid using fresh chicken manure in your garden. While it's a wonder stuff, its acidity breaks down the surface of the zinc faster, putting the steel at risk of rust. Instead, use composted chicken manure or another organic option.
Choose plants that grow in neutral soil and keep the soil pH on the neutral side. At neutral levels, zinc is less likely to break down into the soil.
If you're growing plants that like acid, consider using a liner. Heavy plastics prevent acid soil from coming into direct contact with metals. Just make sure the plastic only covers the sides to ensure good drainage.
Modify heavy clay to loosen it. Well-drained soil is necessary for breeding beds to ensure they don't turn into muddy ponds. Also, clay is such a fine particle that it can stick to the sides of your bed, and caked clay layers can cause more damage to the zinc surface than sandy soil.
So what have we learned? The zinc coating is safe enough that it is used for livestock feeding and drinking water. It's less likely to seep into your food. Steel garden containers are unlikely to get too hot for your plants. Best of all, you can grow healthy food in it. Commercial containers are available and are easy to assemble and can be grown quickly. If you're good with tools, you can also make your own. There are also ways to extend the life of your bed, which has lasted for decades.
Not only is it safe to grow plants on galvanized steel beds, but you will grow better food than you can buy at the market. So consider gardening in these cute containers!