Raised Garden Bed: Advantages, Preparation, and Building

Kenneth Wilson

After adding landscaping features, installing outdoor structures, and maintaining the turf, the next thing you could do is to plant fruits, vegetables, or flowers in your yard. Starting a garden can be difficult, especially if it’s your first time. But it doesn’t have to be that way! You can make gardening easier by using raised garden beds.

It can be challenging to start a garden in Florida, especially since our soils aren’t always the best for growing fruits, vegetables, or flowers. That’s why some people use raised garden beds or gardens in a box.

It may sound complicated but it’s not that difficult to build. You even have options to construct from scratch or buy a kit to install in your yard. There are more reasons why it’s great to use raised garden beds, as well as benefits and solutions to some problems gardeners commonly face.

Continue reading to find out what these advantages are, what you need to do before you start building, and how to build a raised garden bed.

What is a raised garden bed?

A raised garden bed, or also called a garden box or raised bed, is a freestanding planting container that is placed aboveground level. It is a box filled with plants and soil but without a top cover.

The box can be made out of different materials such as lumber, rot-resistant wood, bricks, concrete blocks, railroad ties, or landscape timbers. These raised containers are usually placed in a sunny area and filled with high-quality soil. 

Benefits of planting in a raised garden bed

Why should you build or buy a raised garden bed? Because of the benefits of having one! Here are some of the reasons why you should get one:

High-quality soil

This is the perfect solution for those who have soils, like hard clay or nutrient-lacking, which are not suitable for growing plants, fruits, or vegetables. With raised garden beds, you can fill the planting container with good-quality soil, producing a densely-planted garden and gaining more yields.

Aesthetically pleasing

Seeing a raised garden bed filled with colorful plants in your lawn is somewhat similar to seeing a beautiful vase with flowers. Not only does it look wonderful, but it gives a sense of order since there won’t be weeds ruining the picture.

Prevent pests and weeds

Having a raised garden bed makes it easier to manage or control weeds and pests compared to lawn gardens. The box can also help shield the plants from pests.

Comfortable gardening

Since raised garden beds are placed higher, it means you won’t have to bend as low as you would with garden beds on the lawn. When you plant, remove weeds, or collect produce, you won’t have to stoop down, or you can even get a small chair so you can comfortably do your gardening. You can also plant and sow without stepping on tilled soil.

Avoid soil compaction

Since you won’t be stepping on the soil, you can avoid soil compaction. Soil compaction will increase the density since it removes the pores and damages the structure. Preventing your soil from getting compacted will help your plant’s growth as well as allowing water, air, and other nutrients to move better through the soil.

Better drainage

Having a raised garden bed provides better drainage. Having a deep garden bed will prevent water puddles at the root zone unless you already have wet soils.

Providing proper space and sunlight exposure

If you have limited space or plenty of shady areas, you can position a raised garden bed in an area with enough sunlight exposure or a spot in a small yard so that it won’t become a hindrance.

Preparing to build

Before you start constructing your raised garden bed, you should first figure out several things:

Determining the size and depth

If you plan on building your raised garden bed, you have to determine how big and deep you want it to be. Most garden boxes have a width of 3 to 4 feet and a length of 6 to 8 feet. You can change the length to as short or as long as you want it, but make sure not to go over 4 inches for the width. It should be narrow so that you can easily reach all areas, especially when it’s placed by the wall or fence. This will also help avoid stepping into the raised garden, preventing soil compaction. 

The height is also important because if it’s too shallow, then your plants will have a hard time to root. This especially applies to raised beds on a hard surface such as hard-packed soil or a driveway. It is recommended that raised beds have at least a depth of 10 to 12 inches. If you can't do 10 inches, just don't go below 6 inches.

When using wood for your garden bed...

I’ve mentioned that there are different materials that can be used to create a frame such as lumber or rot-resistant wood. For those that want a wooden garden box, here are some details you should know.

If you’re planning to use it for vegetables, you should use untreated lumber since it’s good for edibles. The downside? It won’t be rot-resistant. If you do want rot-resistant wood that is safe for edibles, get one that isn’t treated with arsenic. There are now pressure-treated lumbers preserved with alkaline copper quaternary (ACQ) or micronized copper azole (MCA), using copper compounds as preservatives. It’s considered safer to use, but you can always cover the insides with heavy plastic sheeting to be sure. Make sure to avoid using upcycled wood that is preserved with creosote since this is a potential carcinogen. Another option is using redwood or cedar, which are rot-resistant wood.

Choosing the spot

You can place your raised garden bed anywhere you want - that’s the beauty with it. You’re not limited to your backyard as you can install it on your front yard or driveway. If the area is not level, make sure to adjust the garden bed to the slope. You also have to find an area that provides good drainage, especially if it is on hard-packed soil.

If you’ll be using it for vegetables, make sure to place it in an area with at least six hours of sunlight exposure. It’s also more convenient for you if your garden box is near a source of water and your tool storage box or shed.

To install or not install an irrigation system

You can choose to manually water your raised garden bed or install a drip irrigation system. Since you will need to set up the line running from a rain barrel or tap, make sure to do this before constructing your raised garden bed.

Preparing and choosing the soil

When it comes to the soil, it’s important to get a high-quality one. You can check your local supplier for a mix of nutrient soil and compost. You can also top off the soil with an organic vegetable compost for better growth. Make sure to have sacks of soil in your reserve so you can refill your raised garden bed as needed.

For the amount of soil, here’s how you can compute for it. Measure the width, length, and depth of your raised garden bed and multiply them to determine the volume of your garden box. So if you have a width of 4 feet, a length of 8 feet, and a depth of 2 feet, the volume will be 64 cubic feet. This means you will need 64 cubic feet of dirt, which you can probably get 32 bags of soil with 2 cubic feet of dirt each.

Note: For those who measure in yards, divide the volume by 27 to get it in cubic yards.

How to build a raised garden bed

Now that you’re done planning, it’s time to build your garden bed.

Build the bed frame

Constructing the frame of your raised garden bed isn’t complicated. It can be as simple as stacking two regular 2x4 lumber and creating 4 sets of these. Connect all four and you’ll have a frame or a box with no cover or bottom. Add extra blocks of 2x4 lumber on the corner posts for stability. You can also place these blocks at the center of each set to make the frame more durable.

Note: If you’re planning to build it higher, around one to three feet, you can opt for railroad ties since it is easy to stack.

Fixing the location and getting rid of the grass

Once you’ve built your frame, go to your location and install it. If you will place your raised garden bed on your lawn, place the frame on the spot and outline it with a shovel. Next, you should remove the grass. Use the shovel to remove the grass and then aerate the area with a rake to loosen the soil.

If you’re not in a rush, you can easily get rid of the grass by covering the inside of the outlined area with cardboard then covering it with soil. This will break down the grass, sparing your time and effort. It’s recommended to do this in the fall so that it can quickly break down over the cold season. It’s a long process, but if you will build a large garden bed, this makes things easier.

Before placing the frame

Once the area is ready, you have to add a wire mesh cloth at the bottom of the frame before installing it. This will prevent weeds from growing inside your raised garden bed while still allowing earthworms to get in. Having earthworms inside will enrich the soil, helping the growth of your plants.

If you chose a wood that is not rot-resistant, line the inside of the frame with heavy-duty plastic before adding soil. Actually, you may want to line your frame whether it is rot-resistant or not. Treated lumber may leach copper into your soil, so cover it to be on the safe side.

Note: You may also want to place rocks in the bottom of your raised bed, especially if your garden bed has a depth of 18 inches or more. Why? It will even improve the drainage. By adding rocks, this will increase the drainage space below the soil. If there is excess moisture, roots can rot and this may damage or kill your plants. Adding rocks will also help your plants survive even if your soil becomes compacted as there is extra space at the bottom for water to drain away. With rocks or pea gravel, you won’t have to replace these as they do not degrade nor compact.

Adding the soil and plants

Add the right amount of soil and put int your plants. Make sure to keep the soil loose around your plants to allow water to reach the roots.

You may also want to add stakes. If you add a couple of midpoint stakes, this will help prevent beds from shifting.

Final touches

You’re actually done after adding the soil and planting, but there are some extra features you may want to consider. You can add a mesh cover to keep birds and other animals away from your raised garden bed. To make it more aesthetic, you can also install a trellis covered with vines, which can also shield your raised garden box.

Raised Garden Bed on Paved Areas

For those who will be placing their raised garden bed on paved areas, here’s a video on how to make it:

It’s similar to the steps when building a raised garden bed for your lawn, but this time, you’ll need to add a bottom. Using the same lumber for the frames, create planks and place them at the bottom. Make sure to space them apart for drainage.

Next, staple a layer of chicken wire on top of these planks. This will keep animals that can climb under the garden bed. This will also keep the landscape fabric from sagging in between the planks. So yes, you will also need to add a landscape fabric at the bottom. Make sure to not stretch it out so that it won’t rip from the weight of the soil.

Kenneth Wilson
March 2, 2020
Yard & Garden

Kenneth Wilson

Retired contractor. Currently residing in Southwest Florida. Now in semi-retirement, I write and manage this blog focused on helping home owners make savvy decisions when it comes to finding contractors and getting their projects done. I also operate remodeling design service for homeowners.

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