If you're thinking of filling a metal raised garden bed you should plan to put something under it. Not only does it provide adequate drainage, but it also protects your chosen garden bed soil mixture from direct sunlight and prevents weeds from growing. Here are some of the fillings you might use for the bottom of your Anleolife garden bed
Those who wish to place organic materials at the bottom of a raised bed garden may consider using wood chip mulch. Although they do not provide the same drainage as gravel, they can be easily added in a way that still provides a good flow of water, and they decompose over time, replenishing the native soil below. However, you should try to avoid using pressure treated wood because chemicals may still leach into the soil. So make a thick layer of organic matter, and line the bottom with wood chips, then a layer of grass chips, hay and leaves.
Gravel or river stone
Other popular choices at the bottom of metal raised garden beds are pea gravel or river stone. It provides drainage, allowing any excess water to drain away from the roots of the plant. Because it does not decompose, it has a longer service life than other materials that are more prone to decay over time. However, it can be more expensive.
Pine needles have many benefits. They are a viable option for the bottom of metal raised garden beds because they tend to retain moisture and decompose slowly, meaning they will improve the soil in the garden bed over time. Pine needles also provide a natural covering that can help keep the garden hydrated when it's hot and dry outside.
This may be a good alternative to using landscape fabrics. This may not last any longer than the latter, but it can be left under the raised garden bed before it completely disintegrates. Because of the gap between its threads, it allows water to pass through and provides better drainage for your metal raised garden bed. It is made from jute plant fiber, therefore, it is environmentally friendly.
Geotextile or landscape fabric
Another popular option, especially for those looking to minimize the time they spend maintaining garden beds, is landscaping fabrics. The fabric can be bought at most home improvement stores and provides good drainage as well as preventing weeds from growing from the bottom of metal raised garden beds. Landscape fabrics are not as durable as gravel or river stone, but are relatively inexpensive.