How to Fill Raised Garden Beds

If you're looking to optimize garden space and increase yields, raised garden beds are worth considering. These practical structures offer numerous benefits, including improved soil quality, drainage, and accessibility.

They are particularly suitable for seniors and individuals with limited mobility and can even be customized with wheelchair pathways. However, before planting, it's important to fill these beds with appropriate materials and soil.

Raised garden beds are elevated and customizable horticultural structures made of materials such as wood, bricks, or galvanized steel. They provide a separate and defined planting space above ground. You can customize these beds to fit various shapes, heights, widths, and colors.

Gardeners utilize these beds to grow a variety of plants, including vegetables, herbs, and flowers. Additionally, raised garden beds can be converted into cold frames to increase protection against unpredictable weather conditions.

Here are five methods to fill raised garden beds:

Core Gardening Method

In the core gardening method, the main objective is to create a sponge-like structure at the center of the raised garden bed. This sponge-like structure acts as a reservoir, retaining water and distributing it evenly throughout the raised garden bed. To fill a raised garden bed using the core gardening method, you will need to:

1.Arrange cardboard at the bottom of the raised garden bed to prevent grass and weeds from sprouting.

2.On top of the cardboard, add a mixture of fresh garden soil or a combination of 1/3 topsoil, 1/3 compost, and 1/3 potting soil or sand.

3.Once filled, dig a horizontal trench in the middle of the bed that is 10 to 11 inches deep.

4.Fill this trench with dry leaves, straw, decayed hay, or straw.

5.Cover the raised garden bed with 1 to 2 inches of compost.

The core gardening method provides a budget-friendly solution that reduces the need for constant irrigation.

Hugelkultur Method

Hugelkultur is a German gardening method that involves creating a raised garden bed filled with decomposing wood, compost, mulch, and other organic materials. This creates nutrient-rich soil with excellent moisture retention and drainage capabilities. To fill a raised garden bed using the Hugelkultur method, you will need to:

1.Lay down logs and branches of rotting wood and less rot-resistant tree limbs (such as birch, willow, and beech) in the raised garden bed.

2.Add straw, dry hay, and grass clippings on top of the rotting wood. Ensure this layer is free from chemicals or pest infestation.

3.Incorporate shredded bark, newspapers, fallen leaves, or cardboard on top of the straw. This layer will accelerate the decomposition of the first layer (wood) and the second layer (straw).

4.Add 1 or 2 inches of compost to provide nitrogen to your raised garden bed.

5.Add 1 or 2 inches of topsoil and natural mulch to prepare the bed for your planting.

Ruth Stout Method

Ruth Stout introduced a low-maintenance gardening method called "no-dig, no-work" gardening. This technique involves filling raised garden beds with leaves, straw, hay, and kitchen waste. To fill your raised garden bed using the Ruth Stout method, you will need to:

1.Layer your raised garden bed with organic kitchen waste and garden residues, such as tree prunings, grass clippings, and fallen leaves. Make sure everything you add is chemical-free and disease-free.

2.Place a layer of 8 inches of leaves, decayed hay, or straw on top.

The Ruth Stout method is a permanent cover system that offers various benefits, including improved water retention, prevention of soil erosion, and increased soil fertility.

With this method, if you encounter any issues, the solution is more cover. For example, if you see weeds or pests, or if the ground beneath all the cover is too wet, add more cover to address the problem.

Sheet Mulching

Sheet mulching, also known as lasagna gardening or composting, is a no-dig, no-till method for raised garden beds. It involves layering multiple materials, both brown and green, to create a rich and nutrient-dense soil for plants. To start a sheet mulch garden, you will need to:

1.Begin with 4 inches of branches and small twigs to promote drainage.

2.Add 2 to 8 inches of brown materials, such as shredded newspaper, cardboard, or dry leaves. Moisten this layer with water.

3.Add 2 inches of aged compost or decomposed manure, followed by 2 to 4 inches of green materials, such as kitchen scraps, grass clippings, and coffee grounds.

4.Repeat the alternating layers of brown and green depending on the size of the raised garden bed, ending with a brown layer. Water deeply each time you add a brown layer.

5.Cover with 6 inches of topsoil and start planting.

Bulk Soil

While it may be tempting to save money by filling raised garden beds with regular garden soil, it is not the optimal choice. Garden soil tends to compact easily, and cheaper versions degrade organic matter and nutrients rapidly.

Garden soil is heavy and can suffocate plant roots if not refreshed and modified with amendments or soil conditioners like compost or vermiculite. To improve drainage and enhance soil structure and fertility, mix 6 parts topsoil with 3 parts compost and 1 part potting soil.

Another option is to mix 2 parts vermiculite with 4 parts soil and 4 parts compost. To fill raised garden beds with bulk soil, you will need to:

1.Layer your raised garden bed with 6 inches of branches, sticks, or other small organic garden debris to promote drainage.

2.Add soil on top and start planting.

While you can customize your raised garden bed, these structures are typically 4 feet wide and at least 12 to 18 inches deep.

Note: To calculate how much soil you need, multiply the length, width, and depth of the raised garden bed. For example, if your raised garden bed is 8 feet long, 4 feet wide, and 2 feet deep, you will need 64 cubic feet of soil.

Filling raised garden beds involves selecting the right planting materials or following specific gardening methods like sheet mulching or the Ruth Stout method. How to fill raised garden beds will depend on the materials you have and your budget.

By choosing the appropriate filling method, you can create a nutrient-rich and well-draining environment that promotes healthy plant growth in raised garden beds.