How to Build a Raised Garden Bed – Mother Earth News (2024)

For those who want to improve their backyards, author Sara Bendrick provides a variety of DIY projects in Big Impact Landscaping so homeowners can get the most out of their property, expand their living space, and enjoy more time outdoors. Here, Bendrick gives step-by-step instructions for building a permanent U-shaped vegetable garden box — as well as an attached bench to help you enjoy your backyard plants.

Photo by Joe Dodd

U-Shaped Vegetable Garden

Level: Beginner to intermediate
Cost: $$
Time commitment: 1 day
Professionals needed: None
Dimensions: 8-feet-by-9-feet U-shape

Garden beds make any yard come alive, and the best part about having a raised bed is that it looks attractive even in the off-season because it defines and organizes the space in the yard. A simple U-shaped bed gives you maximum growing space with all-around access. Adding a cute little bench to the cap and some decorative diamonds can really dress it up! This large garden can be a focal piece or complement other features in the yard. Plan to hand water unless you want to install an irrigation system (I prefer drip).
How to Build a Raised Garden Bed – Mother Earth News (1)

Drawing by Sara Bendrick

Tools

• Measuring tape
• Pencil
• Miter saw or circular saw
• 2-to-3-inch level
• Shovel
• Rake
• Hand tamper
• Impact driver or drill and socket bit
• String line
• Speed square
• Stakes
• Clamps
• Hose with multispray nozzle
• Finish nail gun (optional, if not using deck screws)

Materials

• Three 2-inch-by-12-inch-by-10-foot boards, two cut into 9 feet and one cut into two 51-inch pieces
• Two 4-inch-by-4-inch-by-8-foot redwood boards, cut into eight 22-inch pieces
• Eight 2-inch-by-12-inch-by-8-foot boards
• Four whole
• Four cut to 5-feet-6-inches
• Six 2-inch-by-4-inch-by-10-foot boards (wait and cut based on your actual dimensions in case they vary a little) (cap)
• Two 2-inch-by-4-inch-by-8-foot boards, each miter cut to make twelve 15-inch pieces (diamonds)
• One 2-inch-by-6-inch-by-10-foot, cut to two 51-inch boards (bench)
• 1/3 cubic yard of 3/4-inch gravel
• Thirty-two 3-1/2-inch-by-3/8-inch lag bolts and washers
• 3/8-inch drill bit
• 3-1/2 cubic yards of garden soil
• One 1-pound box of 2-1/2-inch deck screws
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Photo by Joe Dodd

Step 1: Select your location: Pick a nice sunny area that is fairly level and easy to get to.

This garden box will fit in a 9-by-9-foot space; you can adjust yours to be bigger or smaller depending on your area. However, I don’t recommend going smaller than 30 inches (2-1/2; feet) for the arms, as it gets too tight to plant two rows of veggies.
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Photo by Joe Dodd

Step 2: Select and cut your lumber: I used “merch” redwood, which is really rough and imperfect redwood, as it drops the price significantly and works great for a rough, rustic veggie bed. I recommend using raw redwood or cedar for planters. Never use pressure-treated lumber for a vegetable garden. With a miter saw, cut all your lumber to the specified dimensions above or adjust for your own space.
How to Build a Raised Garden Bed – Mother Earth News (4)

Photo by Shutterstock

Step 3: Grade your level: Most sites are going to need some slight leveling or be cut and filled to get an even surface. You have two options: dig out the high areas and transfer the soil to the low areas or build up the whole space with the 3/4-inch gravel. Compact it with a hand tamper and use a rake to level it out.
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Photo by Shutterstock

Step 4: Start with the back: Since we are placing this planter against a fence, start with the long back pieces by assembling them on the ground. To do this, take one 9-foot board and line it up with one of the 22-inch, 4-by-4 posts. The bottoms should line up square and overhang the side by 1-3/4 inches or by the width of your lumber, as a sidepiece will fit in there later. Use two 3-1/2-inch lag bolts and washers to attach about 2-1/2 inches down from each edge so that they are roughly in the center of the 4-by-4. Predrill holes as shown in step 5 and secure as shown in step 6. Attach a second 9-foot board above the first in the same manner and then attach a second 22-inch 4-by-4 post on the other side, still leaving a 1-3/4-inch gap on the end.

Now take an 8-foot 2-by-12-inch board and slide it in to match the bottom board height and into the overhanging space. Secure with the same bolt and washers as described above and repeat on the other side.
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Photo by Joe Dodd

Step 5: Predrill the holes: Use a 3/8-inch drill bit to predrill your lumber as you go before inserting screws, which will help prevent splitting and will guide your lag bolt into the lumber.
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Photo by Joe Dodd

Step 6: Secure the lumber: Use a socket bit with an impact driver to secure the two pieces of lumber together with lag bolts and washers on each end. Lag bolts are heavy-duty screws that are best for securing thick lumber.
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Photo by Joe Dodd

Step 7: Run a string line and add the sides: Prop up the back and make sure that it is sitting level. Secure a string line to the back and pull the line so that it is perfectly perpendicular, using a speed square to check that it is 90 degrees. Secure it to another structure or tie it to a stake in the ground. Take one of your 8-foot boards and slide it into the 1-3/4-inch overhanging edge, referencing the string line, and secure with lag bolts.
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Photo by Joe Dodd

Step 8: Attach the front: Using a clamp or an extra pair of hands, attach a 30-inch 4-by-4 front piece to one of the sides. Clamps are great if you need to force a warped board into place.
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Photo by Joe Dodd

Step 9: Check your level: Use a level to verify that you’re building straight up and then attach the 30-inch piece to the 4-by-4 post with bolts.
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Photo by Joe Dodd

Step 10: Add the top layer of wood: Drop in the top side pieces, predrill and secure with bolts, as you did in steps 5 and 6, except this time you’re building in place. The top layer will sit a few inches taller than the 4-by-4, so that when you fill with soil you can cover the top of the 4-by-4 to make it disappear.
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Photo by Joe Dodd

Step 11: Finish the box: Continue building the box by finishing the “legs,” or the 8-foot sides, the 30-inch front and the 5-foot-6-inch inner side on both sides of the planter. Your 4-by-4 posts on the inner part of the planter should sit flush with the end of the 5-foot-6-inch boards. Then take the 51-inch 2-by-12 boards and attach them to the 4-by-4 posts, closing the box so that you have a U-shape.
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Photo by Joe Dodd

Step 12: Add gravel and dirt: Add a 2-inch layer of gravel to the bottom to help with drainage. Then fill the box up with 3-1/2; cubic yards of garden soil. After filling the box a few inches deep, use a hose to mist the soil down to help compact it and make it moist for your new plants, and use a rake to spread it around. Repeat this step until the container is filled to about 2 inches below the lip and the soil just covers the 4-by-4 inside posts. For this amount of soil it’s probably easiest to get it delivered in bulk from a landscape supply store, or you can buy it in bags, but it will be more expensive that way.
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Photo by Joe Dodd

Step 13: Add a cap and bench seat: Secure your two 2-by-6-by-51-inch boards on the inside corner of the bench, spacing them 1/2-inch apart. Then take your 10-foot 2-by-4-inch boards and line up a board so that it is flush with the inside edge of the top vertical 2-by-12-inch boards. This will leave an overhang on the outside by about 1-1/2 inches. Make miter cuts on a miter saw to get nice, clean 45-degree angles where the boards overlap in the corners. Use a drill and 2-1/2-inch exterior screws to secure the cap in each corner and about every 12 inches along the long sides and about every 6 feet on the short 30-inch pieces.
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Photo by Joe Dodd

Step 14: Add a decorative backdrop: Use two 8-foot 2-by-4-inch boards and miter cut 12 at 15 inches long to make three separate diamonds. Using 4 pieces per diamond, attach by using a 2-1/2-inch exterior screw on the side. Measure out from the center of the planter and mark 18 inches above on the fence; attach your center diamond using exterior deck screws or a finish nail gun. Space out the other two diamonds about 12 inches away on both sides and secure the same way. Now get planting!

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Photo by Joe Dodd

Modern Concrete and Wood Bench

This simple, modern bench is a functional piece but also drives a strong modern design style throughout the yard. The concrete corners were formed and poured all at once with a gray-colored concrete patio. We built them 18 inches tall and left 4-inch-deep by 11-inch by 6-inch notches for the 4-by-4-inch cedar planks to sit inside. Using a painted angle iron brace attached with redheads to the concrete and with screws to the wood, we were able to secure each of the planks 1/2-inch apart so that no hardware is visible from the top. While simple in theory, getting everything lined up just right is the key to a perfect modern bench. Placing decorative pea gravel raised the ground level so that the benches sat at a standard 16 inches tall. Finishing the space off with a matching lumber coffee table creates a modern and functional entertaining area that ties in perfectly with the other elements of the yard.

Reprinted with permission from Big Impact Landscaping by Sara Bendrick and published by Page Street Publishing, 2017.

How to Build a Raised Garden Bed – Mother Earth News (2024)

FAQs

How to Build a Raised Garden Bed – Mother Earth News? ›

For this method, mark out a rectangle — in a convenient spot in your row garden — that's 3- to 4-feet wide and 6- to 12-feet long. Now dig a 1-foot-deep trench across one end of this space and wheelbarrow the soil to the other end of the planned bed. (You'll later use this to fill the last trench you dig.)

What do I put on the bottom of a raised garden bed? ›

Start with a layer of landscape fabric to prevent soil from washing out. Above this, a layer of gravel or small stones can aid in drainage. Then, fill the bed with a mix of topsoil, compost, and other organic matter. This layered approach ensures good drainage while providing a nutrient-rich environment for plants.

What do you put in a raised garden bed before soil? ›

The best way to save money on soil by filling the bottom of your raised garden beds with leaves is to install the leaves in layers just 6 inches thick at a time. Compress them by walking on them and then wet them with a garden hose. Once that's done, add the next layer.

What is the best soil mixture for raised beds? ›

Add a mixture of compost and purchased topsoil in a 1:2 or 1:1 ratio, to the top of the bed. There are vendors who sell topsoil mixed with compost. Alternatively, fill the bed with compost and a soilless growing mix in a 1:1 ratio.

What layers should a raised garden bed have? ›

How to fill a raised garden bed in six simple steps
  • Step #1: Prepare your garden bed. ...
  • Step #2: Add a drainage layer. ...
  • Step #3: Add a layer of ordinary garden soil. ...
  • Step #4: Add some premium potting mix. ...
  • Step #5: Water the soil to help it settle & add some mulch. ...
  • Step #6: Start planting!
Jan 30, 2023

What is the best filler for the bottom of a raised bed? ›

Plant Waste or Compost

This scoop of “stuff” is a lot of things together. We have a huge pile in the back of our property where we burn leaves, large pieces of wood that we don't want to split, twigs, etc. It's really good to layer all of that stuff in your raised beds as it will break down even more.

Should I put landscape fabric under raised bed? ›

The fact is, landscape fabric is not a necessity if say, you want to control weeds because the confined space makes it easier to control weeds. But, you can use landscape fabric as a raised bed liner for other reasons, such as preventing soil erosion or improving the life of the raised bed itself.

Can you fill a raised bed with just garden soil? ›

Soil taken from your yard or a garden bed is too dense to use in a pot or raised bed. Instead, for containers, you'll want to use potting mix (also called potting soil), a lightweight and fluffy alternative. For raised beds, you'll want to use a blend of potting mix and garden soil.

How many bags of soil do I need for a 4x8 raised bed? ›

As a rule of thumb, a 4'x8' raised bed that is 6 inches deep requires approximately 8 bags of soil while a 4'x8' raised bed that is 12 inches deep requires approximately 16 bags of soil.

How deep should a raised garden bed be? ›

A raised bed does not need to be very deep to be effective, but the surface underneath your garden bed affects which depth is right. In general, eight inches is a good minimum depth for raised garden beds.

What is the difference between garden soil and raised bed soil? ›

Raised Bed Soil is like a balance between garden soil and potting mix. It has the exceptional drainage necessary for container and raised bed gardening. It assists gardeners in maintaining loose soil and provides adequate airflow for necessary oxygen and nutrient delivery to root systems.

What is the first layer of a raised garden bed? ›

To put it simply, you should put a layer of organic material at the bottom of your garden bed, which will break down and enrich the soil. This can include compost, or woody material such as logs, dry wood, branches, and leaves.

How do you layer dirt in a raised bed? ›

If your topsoil and compost aren't already mixed together, dump in a layer of topsoil, then compost, then topsoil, then compost, etc. That way, the compost and soil are evenly distributed without your actually having to mix them. Use a rake to smooth off the soil at the top of the bed.

Should you put rocks in bottom of raised garden bed? ›

Adding rocks to the bottom of a raised bed makes it challenging to amend or improve the soil over time. It restricts access to the lower layers and can impede the addition of organic matter or nutrients. Over time, rocks will get mixed in with your raised bed soil, not cool! Rocks are expensive and heavy!

Should I put anything in the bottom of my planter? ›

One of the best things to put at the bottom of a planter for drainage is broken pieces of pot. You can use any unwanted plant pots or chipped crockery for this – simply smash them up into small to medium-sized pieces. Adding a layer of broken pieces of pot like this will prevent compost loss out of the drainage holes.

Should I put sand in the bottom of my raised garden bed? ›

A strong and stable base is essential for the health and productivity of your raised garden bed. By using the right materials, such as gravel, landscape fabric, sand, compost, cardboard, or soil, you can create a well-draining and nutrient-rich foundation for your plants.

What is the best bottom for a planter box? ›

Spoonemore says, “You can use saucers or trays underneath planters to catch excess water and prevent it from leaking onto floors and furniture. Alternatively, you can place planters on waterproof mats or trays specifically designed for indoor gardening to protect surfaces from moisture.”

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