How to Build a Berm
Plan the shape of your berm., Determine the slope and height., Consider the drainage., Break up the soil lightly., Build the base from affordable materials ., Add the topsoil layer., Compact the soil lightly., Plant on the surface.
Step-by-Step Guide
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Step 1: Plan the shape of your berm.
A berm looks most natural when it follows a curve or sinuous shape, blending into other curves in the landscape.As a guideline, keep the berm about 4 to 6 times as long as it is wide., To minimize problems with erosion, water runoff, and mowing difficulty, keep the maximum gradient below 5:1 (five times as wide as it is tall). 4:1 is possible but risky, and anything steeper requires specialized plants and erosion control.Most berms in home gardens are no taller than 24 inches (61 cm).An asymmetric appearance improves the aesthetics, with an off-center peak and a variety of slopes along the berm's length. , Berms can act as miniature dams, altering the water flow in your garden.
You may need to dig swales between the berms, build a culvert running through the berm, or regrade your garden.You may want to discuss this with a professional landscaper if you are building a tall berm (especially above 24 inches / 61 cm), or if you live in a rainy climate.A flat top reduces runoff and provides more water to plants growing on the side of the berm.While building your berm, do your best to avoid compacting the soil at the base with heavy equipment.
If it's already compacted, loosen the soil by digging 8 inches (20 cm) deep to improve drainage., Dig into the surface of the area along the path of your berm.
This creates a stronger bond with the next layer of soil., With a shovel or bobcat, pile on fill dirt, compacting it periodically.
Shape it according to the layout you decided on, except 1 ft (30 cm) smaller on all sides.
Rake it smooth and get all proportions as exact as possible.Well-compacted clay soil is recommended for steep or tall berms.
Loam will typically collapse at slopes steeper than 35%.Gravel is cheaper, but the soil tends to wash through it — and it is not compliant with some local codes.
If you use it, cover it with at least 1 inch (2.5 cm) of compacted clay., Spread out a layer of topsoil over the entire berm, mixing it with the top 2–3 inches (5–7.5 cm) of clay.Pile on more topsoil to form a layer 1 ft (30 cm) thick. , Roll an empty lawn roller over the top layer of soil, or tamp it down with your feet or a board.The berm will settle over time as water seeps through it, but a light compaction should be enough to minimize erosion. , Establish a lawn over the berm, along with shrubs and trees in a pattern that doesn't interfere with mowing or walking.
Add mulch while the plants are establishing roots to prevent erosion. -
Step 2: Determine the slope and height.
-
Step 3: Consider the drainage.
-
Step 4: Break up the soil lightly.
-
Step 5: Build the base from affordable materials .
-
Step 6: Add the topsoil layer.
-
Step 7: Compact the soil lightly.
-
Step 8: Plant on the surface.
Detailed Guide
A berm looks most natural when it follows a curve or sinuous shape, blending into other curves in the landscape.As a guideline, keep the berm about 4 to 6 times as long as it is wide., To minimize problems with erosion, water runoff, and mowing difficulty, keep the maximum gradient below 5:1 (five times as wide as it is tall). 4:1 is possible but risky, and anything steeper requires specialized plants and erosion control.Most berms in home gardens are no taller than 24 inches (61 cm).An asymmetric appearance improves the aesthetics, with an off-center peak and a variety of slopes along the berm's length. , Berms can act as miniature dams, altering the water flow in your garden.
You may need to dig swales between the berms, build a culvert running through the berm, or regrade your garden.You may want to discuss this with a professional landscaper if you are building a tall berm (especially above 24 inches / 61 cm), or if you live in a rainy climate.A flat top reduces runoff and provides more water to plants growing on the side of the berm.While building your berm, do your best to avoid compacting the soil at the base with heavy equipment.
If it's already compacted, loosen the soil by digging 8 inches (20 cm) deep to improve drainage., Dig into the surface of the area along the path of your berm.
This creates a stronger bond with the next layer of soil., With a shovel or bobcat, pile on fill dirt, compacting it periodically.
Shape it according to the layout you decided on, except 1 ft (30 cm) smaller on all sides.
Rake it smooth and get all proportions as exact as possible.Well-compacted clay soil is recommended for steep or tall berms.
Loam will typically collapse at slopes steeper than 35%.Gravel is cheaper, but the soil tends to wash through it — and it is not compliant with some local codes.
If you use it, cover it with at least 1 inch (2.5 cm) of compacted clay., Spread out a layer of topsoil over the entire berm, mixing it with the top 2–3 inches (5–7.5 cm) of clay.Pile on more topsoil to form a layer 1 ft (30 cm) thick. , Roll an empty lawn roller over the top layer of soil, or tamp it down with your feet or a board.The berm will settle over time as water seeps through it, but a light compaction should be enough to minimize erosion. , Establish a lawn over the berm, along with shrubs and trees in a pattern that doesn't interfere with mowing or walking.
Add mulch while the plants are establishing roots to prevent erosion.
About the Author
Pamela Coleman
Enthusiastic about teaching crafts techniques through clear, step-by-step guides.
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