How Deep Should You Make Your Garden Bed?
Raised garden beds are a good way to reconnect with nature without breaking back or knee pressure. The raised garden bed is very suitable for the elderly gardener and the people with mobility difficulties. They are also the best choice for narrow spaces because they can be customized to accommodate different heights and widths.
Raised garden beds improve soil structure and drainage, which is essential for the healthy growth of plants. In other words, all the benefits of a raised garden bed are directly related to its height above the ground. But how deep should your raised garden bed be? Below is more information about raised garden beds and why their structure, size and depth are important.
Type of raised garden bed
Raised garden beds are popular solutions for gardeners with poor structure and nutrient deficiency. They can range from simple earth piers to semi-permanent structures that need to be assembled. The following is a brief introduction of the different types you can consider.
- Container type raised garden bed
Starting from the most exquisite raised garden bed, the container garden bed is a high wall, most of which are permanent structures and used as garden flowerpots. The wall of the container garden bed can be as high as 12 inches, even 27 inches, for wheelchair users, emphasizing its user-friendly function.
The durability of its structure ensures the consistent conditions of plants and prevents human flow and pets. You can use galvanized steel or untreated wood to build your own, but many ready-made elevated container beds can be used commercially. Please check the garden bed provided on the OlleGarden line.
- Earth mound garden bed
Pier garden bed is very laborious to build, but it requires very little materials. First of all, find your gardening area, because this is where you want to build mounds. Make sure it receives enough sunlight and is not on the slope, because water may erode the mound.
After that, it began to accumulate soil free of pathogens, pesticides and weeds. You can also choose to create a lasagna garden on the garden bed, which includes layering additional soil with green and brown materials, such as fresh grass, organic kitchen residue and straw.
These layers cultivate beneficial microorganisms, decompose the green layer and maintain heat, thus improving the soil structure and promoting the healthy growth of plants. The average height of the mound bed is 6 to 8 inches. Although there is no boundary to provide many passages, the raised garden bed is vulnerable to the impact of human traffic and other invasions.
In terms of maintenance, the mound needs to be regularly reshaped to ensure that it will not become compacted or dispersed, because it will interfere with the roots of developing plants.
- Edge garden bed
The elevated garden bed with the edge provides similar protection to the container-type garden bed, but has the simplicity of a mound garden bed. In addition, you can use everyday materials to create frames or supports, such as extra scrap on wooden pallets.
After stacking the mixture of soil and organic materials, you can frame the pile with bricks, stones or untreated wood. Avoid railway sleepers because they are treated with toxic compounds, which will seep into the soil and be absorbed by plants. You can even check the garden bed keyhole garden to see if it is suitable for you.
Like the lasagna garden, you can garden and compost at the same time as the keyhole garden. These gardens look like a pie. Take out a piece to facilitate access to the compost bin in the center. By placing a nutritious composting system in the middle of the garden, all your plants can be utilized and thrive.
Soil depth and raised garden bed
Is the planting pattern of shallow soil and deep soil suitable for raised garden beds? Or is a raised garden bed just a beautified "stilt garden" that has not been adequately reviewed?
Soil depth is critical to plant growth because it measures the depth of plant roots that can develop in the blocking layer on the soil surface. The blocking layer includes cement, dense clay, coarse sand, gravel or rock.
Depth category (underground garden) range:
The deep soil surface is 60 inches away from the layer that hinders root development.
At medium depth, its surface is 20 to 36 inches away from the layer hindering root development.
The deep soil surface is 36 to 60 inches away from the layer that hinders root development.
Its surface is 10 to 20 inches away from the layer that hinders root development.
The surface of very shallow soil is less than 10 inches from the layer that hinders root development.
Through the raised garden, you can control the soil, different layers and organic materials used to produce growth media. However, even in this case, the depth of the raised garden bed is very important! It can make the roots of your plants have enough space to stretch without being bound or restricted by the roots.
How deep should your garden bed be?
The depth of the garden bed can be between 6 and 24 inches, of which 10 inches is a good starting point. If you plant vegetables on the garden bed, your soil should be 12 to 18 inches deep.
The construction, filling and maintenance of deeper garden beds are costly and may be difficult to access. If you want to plant deeper, a mound garden bed will be ideal, because the roots of plants can continue to develop to the soil surface under the pile.
That is, if you prefer to plant crops on the raised garden bed, there are cheaper ways to fill the deeper garden bed. In addition to the huge cultural method, you can also check the RuthStout method, the lasagna and the core garden.
The problem of planting too shallow
The deeper soil not only contains more nutrients than the shallow soil, but also provides enough space for plants to ground. Deep planting can protect plants from the influence of elements and provide a buffer system to withstand cold and hot temperatures.
On the other hand, shallow planting has its own series of problems.
- Side wall compaction
When you sow or plant too shallow seedlings in the ditch, the soil may be compacted or smeared, resulting in soil drying. This may lead to poor root development and germination.
- Vulnerable to herbicides
As the sidewall is compacted, seeds or seedlings may be exposed to herbicides on the soil surface. Because the soil is not too deep, the herbicide will continue to concentrate on the top of the soil a few inches.
When combined with the cold and wet conditions on the soil surface, the sprouted plants will not be able to metabolize herbicides, which may lead to slow growth and discoloration.
- Poor root development
When the roots of seeds develop, they will appear about an inch above the growth medium to sense sunlight. Because the shallow soil is heated faster and can be "baked" under direct sunlight, the sprouted buds will appear on the hot and dry surface, either dry and dead or stunted.
Tall and grounded!
The depth of the raised garden bed may seem a bit random, but it also depends largely on the type of garden bed you have. The container bed may contain deep soil, but it may be expensive, and the raised bed of the mound is a little shallow, but your plants can continue to develop to the ground below the mound.