If you plan on building a raised garden bed, it’s essential to consider what you should put at the bottom. There are several options depending on your needs and goals. To prevent weeds from growing beneath the bed, you can lay a barrier, such as cardboard or landscaping fabric.
Adding rocks or gravel to the bottom can help improve water flow if you have poor drainage. Adding a layer of compost or other organic matter can benefit soil retention and overall garden health. If you’re dealing with burrowing pests like gophers or moles, lining the bottom of the bed with wire mesh can help keep them out. By taking the time to consider your garden’s unique needs and selecting the appropriate materials for the bottom of your raised garden bed, you’ll help ensure a successful growing season.
There are several reasons why you might want to place something at the bottom of a metal garden bed:
Weed Prevention: By laying a barrier, such as cardboard or landscaping fabric, at the bottom of the bed, you can prevent weeds from growing up beneath the bed and invading your garden.
Drainage: If your garden bed doesn’t have good drainage, placing some gravel or rocks at the bottom can help water drain away more quickly.
Soil Retention: Adding a layer of compost or other organic material to the bottom of the bed can help retain moisture and nutrients in the soil, allowing your plants to thrive.
Pest Control: Lining the bottom of the bed with wire mesh can prevent burrowing pests like gophers and moles from accessing your garden.
Adding something at the bottom of your metal garden bed can help improve soil quality and prevent common problems.
Materials you can put on the bottom of modular metal raised garden beds: there are many options for what to put on the bottom of your modular metal raised garden bed to avoid poor drainage, including pea gravel, weed-blocking plastic, landscape fabric cloth, and much more. The best option for your modular metal raised garden bed will depend on many things, including the cost and time you want to spend maintaining your garden bed.
2. What can be placed?
2.1- gravel or river stone
Pea gravel or river stones are among the most popular options for modular metal raised garden bed bottoms. It provides drainage, which allows any excess water to drain away from plants’ roots.
Additionally, because it does not decompose, it will last longer than other materials and will be more prone to rot. However, it can be more expensive.
2.2- Geotextile or landscape cloth
Another popular choice, especially for those looking to minimize the time they spend always maintaining their modular metal raised garden beds, is landscaping fabric.
This fabric can be bought at most home improvement stores and provides good drainage and weed prevention from growing up from the bottom of a modular metal-raised garden bed. Landscape fabric will not last as long as gravel or river stone, but it is relatively inexpensive.
Some gardeners use weed-blocking plastic found at most home improvement stores to line the bottom of their modular metal raised garden beds. This material will last longer than the landscape fabric but costs more and cannot be reused once it is damaged (or if it ever becomes damaged over the years).
2.4- wood chips
Those looking to put organic materials on the bottom of their modular metal raised garden bed may want to consider wood chip mulch. Although they do not provide the same drainage as gravel, they can easily be added in a way that still provides good water flow – and they will decompose over time, replenishing the native soil below.
Avoid using those from pressure-treated wood, as chemicals may still leech into the soil. So, to make a thick layer of organic matter, spread wood chips on the bottom, then a layer of grass clippings, hay, and leaves.
2.5- newspaper or cardboard
Depending on the size of your modular metal raised garden bed, you can put 4-6 layers of newspaper or cardboard (no glossy paper) at the bottom. Then, you only need to worry about adding planting mix on top of this layer.
It is recommended not to use colored paper because it contains heavy metals.
The benefits of this method include not spending on new ones since you can use those around your house, and it prevents having to use a weed mat, which can be difficult to remove once your vegetables or flowers take off.
This will also suppress the growth of weeds, which means less weeding. If you do not wish to put newspaper at the bottom, you can still put newspaper as a weed barrier on top of the weed mat.
2.6- weed fabric
Another popular option is weed fabric, often called “weed cloth.” This material can be bought at most home improvement stores and provides good drainage and weed prevention from growing up from the bottom of a modular metal-raised garden bed. The downside to this material is that it does not last as long as gravel or landscaping fabric, so it must be replaced more often.
2.7- plastic sheeting
Many gardeners use plastic sheeting to line the bottom of their modular metal raised garden beds. This option is less expensive than landscape fabric but provides similar benefits. The downside to this method is that the material will not last as long.
2.8- pine needles
Pine needles have a lot of benefits. They are a viable choice for the bottom of modular metal raised garden beds because they tend to retain moisture and decompose slowly, which means they will improve the modular metal raised garden bed soil over time. Pine needles also provide a natural mulch that can help conserve moisture in your garden when it is hot and dry.
Pine needles can also help prevent weeds from entering your modular metal-raised garden bed because they decompose slowly. As a natural product, they do not contain any weed-killing chemicals, so you will not have to worry about them hurting the plants in your modular metal-raised garden bed as they break down over time.
2.9- rubber mulch
Rubber mulch is another excellent option for the bottom of your modular metal raised garden bed. Rubber mulch is a viable option to avoid using landscape fabric or gravel. It is more expensive than other options but provides benefits like preventing weeds and retaining moisture in drought. This product tends to be made with recycled tires, making it a sustainable option and delivering the benefits of rubber as it breaks down over time.
Recycled tire mulch is easy to clean – you can hose it down and use a small shovel, rake, or leaf blower to remove clippings that fall into the bed.
Rubber mulch is available at most hardware stores and home improvement centers. It can be expensive but will last for years without odor or weed growth.
2.10- coconut fibre
This organic material has many benefits over other materials for modular metal raised garden beds. One of the most significant benefits of coconut fiber is that it does not break down like other materials. Different types of mulch will break down over time and need to be replaced, increasing the expense of raised bed gardening. Coconut fiber is a sustainable option that does not require replacement, which can help save money in the long run.
Coconut fiber also acts as a regulator of soil temperatures for your plants. It helps to retain heat in the soil, which means that your vegetables will be able to grow well even during the hot summer months. In areas with freezing nights or mornings, coconut fiber can also help to keep the soil from cooling too quickly – making it a good option for anyone who lives in an area where sudden changes in the temperature can damage plants.
Coconut fiber can be used as a substitute for gravel at the bottom of your modular metal raised garden beds. This makes it an extremely cost-effective material to use around your vegetable plants. This mulch also helps retain moisture in the soil mix, so you will not have to water every day or two as you do with other mulches.
2.11- Plastic cloth
This material is made with recycled plastic. It is a biodegradable mulch that can be used in modular metal raised garden beds for vegetables, flowers, and other types of plants. It comes in rolls or bags.
One of the benefits of using treated mulch is that it contains an anti-weed compound. This means you will not have to worry about growing weeds in your modular metal-raised garden bed. It can also help suppress weed growth for several weeks after adding it – even if the mulch is no longer visible.
Treated mulch is less readily available than other mulches and is more expensive. However, it does provide many of the same benefits as different types of mulch at a low price point. Most modular metal raised garden beds will also get quality soil over time with this material because it decomposes slowly.
Another benefit is that treated mulch does not contain any weed-killing chemicals, which means your garden will be safe for animals and people if they accidentally come into contact with it. It also has no unnatural or harmful odors, which is another big benefit over other types of mulch.
Treated mulch comes in assorted colors and can be used to improve the overall aesthetics of your modular metal raised garden bed. Many people are drawn to this mulch because it helps their garden look better than using other mulch.
2.12- burlap sack
This can be a great alternative to using landscape fabric. This may not last longer than the latter, but it can stay under the modular metal raised garden beds before decomposing completely.
Thanks to the gaps between its threads, it lets the water pass through and provides better drainage to your modular metal raised garden beds. It is eco-friendly since it is made from jute plant fibers.
One main drawback of using this material is that the edges fray easily. It may wear out in time, especially when exposed to environmental elements. This can make it look messy and hasten its decomposition. Over time, it may cost you more as you must constantly replace it.
2.13- Rat or gopher stainless steel mesh
If you are worried about burrowing animals affecting your modular metal-raised garden beds, you can use this durable material underneath the bed to keep these animals out. This also ensures that gophers or rats will not target plants such as root crops. Just ensure you staple them in place to prevent them from shifting around.
Whichever option you choose, make sure it is at least 4″ thick – the thicker, the better. Most require a 4″ layer to provide drainage effectively – anything less may not do the trick.
If you are building your modular metal raised garden bed, make sure to put drainage holes (1/8″) in the bottom of the modular metal raised garden bed garden before placing anything on top of it. Doing this will allow excess water to drain away from the plant roots and ensure they do not become waterlogged or soggy.
Number one rule to consider in building modular metal raised garden beds: Aside from choosing the materials you will be putting on the bottom of your modular metal raised garden beds, the rule you must consider is putting in good garden soil for your plants. Also, since all sides of the modular metal raised garden bed are accessible, you will never have to step on the ground.
The advantage of a modular metal raised garden bed is that you get light and fluffy, well-drained, excellent soil that will help give you vigorous plant growth. Since there is no chance for you to step on the ground, the aeration and soil level will not reduce and prevent the activities of valuable microorganisms from getting affected.