Although garden bed kits are an easy way to build a raised garden bed, unfortunately, many of these kits use wood that is too thin. That’s why we’re giving you a step-by-step guide on how to build a raised garden bed with supplies from your local home improvement store in 10 easy steps.
This tutorial tells you how to shop for the lumber and tools needed to construct a garden bed 4 feet wide x 8 feet long x 1 foot deep, how to modify the lumber for garden beds of different sizes, and why you should use untreated wood. And since you can’t grow a vegetable garden without good soil, this tutorial helps you get started with that, too.
If this is one of those DIY projects that you’d rather not work so hard on, you can take your chances with a garden bed kit. They come in multiple materials and sizes. But for a customized garden bed that can be modified to fit your needs and the shape of your garden space, keep reading!
How to find the right tools and materials
In this tutorial, we’re building a raised garden bed with the dimensions 4 feet wide x 8 feet long x 1 foot deep. The tools and materials we describe are for a bed of this size.
The depth will be 1 foot or 12 inches. Most lumber comes in a height of 6 inches. To achieve a depth of 1 foot, two boards will be stacked on top of each other and held together by framing angles on each end of the boards.
Tools and materials needed:
- Untreated, durable, long-lasting wood. Cedar is the best choice.
- Framing angles
- Hex screws
- Washers
- Nuts
- Drill
- Drill bits
- Tape measure
- Pencil
- Bolt tightener or wrench
- Framing square
You may already have some of these tools in your toolbox, like a pencil, tape measure, and wrench. You can easily find any supplies you don’t have at a local hardware store or online from retailers like Home Depot, Lowe’s, and Amazon. Next, we’ll explain in greater depth exactly what to look for when shopping for the items on this list.
Untreated, durable, long-lasting wood
Cedar is the best choice. Lumber typically comes in a standard size of 2 inches thick, 6 inches in height, and 8 feet long, or 2” x 6” x 8’. The dimensions may be different if you purchase wood from a lumber yard.
Choose untreated wood readily available at your local home improvement store. Pressure-treated wood has been treated with chemicals that can leach into your soil and precious fruits and veggies. Painted wood poses the same risks.
Untreated cedar boards are a good choice because they are durable and long-lasting. They are rot-resistant and will last about 10 to 15 years. Although pine is the least expensive wood, it will only last a few years. More rot-resistant woods include redwood and locust. Make sure boards are as thick as possible, at least 2 inches thick. In general, thicker boards last longer.
Where to find 2-inch-thick untreated wood boards:
- Lowe’s: 2-in x 6-in x 8-ft Cedar Rough Air Dried Lumber
- Home Depot: 2 in. x 6 in. x 10 ft. #2 and Better Prime Douglas Fir Board
- Home Depot: 2 in. x 6 in. x 92-5/8 in. Prime Kiln Dried Whitewood Stud
Framing angles
Buy four framing angles that are 12 inches long. These will connect the boards to create the walls (sides) of your garden bed. Select framing angles that are tall enough to attach two boards perpendicular to each other.
Where to find 12-inch framing angles:
- Amazon: Rok Hardware 12″ Heavy Duty Metal Corner Bracket Right Angle Structural Brace, 18 Gauge, Zinc Finish (Single)
- Home Depot: 1-1/2 in. x 12 in. Zinc-Plated Slotted Angle
- Walmart: Stanley Hardware 182741 Steel Slot Angle 14 Gauge 1.5 x 12 In.
Hex screws
Purchase screws 2.5 inches long. You will need 16 for a smaller box and 24 for a larger box. Screws should fit the holes of the framing angles and be fully threaded, which means the threads should go all the way to the screw head.
Two hex screws can be used on each end for shorter beds, for a total of four per board. For larger beds, three hex screws can be used on each end, for a total of six per board.
Where to find 2.5-inch full-thread hex screws:
- Home Depot: 1/4 in. x 2-1/2 in. External Hex Full Thread Hex-Head Bolts (9-Pack)
- Amazon: 1/2-13 x 2-1/2″ (1″ to 4″ Available) Hex Head Screw Bolt, Fully Threaded, Stainless Steel 18-8 (304), Plain Finish, Quantity 4
- Walmart: 5/16″-24 x 2 1/2″ (PT) Fine Thread Grade 5 Hex Cap Screw (Bolt)
Washers and nuts
Purchase washers and nuts that are 0.25 inches. You’ll buy the same amount of both washers and nuts. Match the screws with the washers and nuts and test them to ensure all the parts fit. You’ll need 16 (for a smaller box) or 24 (for a larger box).
Select hex screws, washers, and nuts that are made with food-grade materials, like stainless steel, to prevent contaminating vegetables and other edible plants.
Where to find 0.25-inch washers:
- Home Depot: Everbilt 1/4 in. Zinc Flat Washer (100-Pack)
- Amazon: 1/4″ Stainless Flat Washer, 5/8″ Outside Diameter (100 Pack)
- Walmart: Bolt Dropper 1/4″ Stainless Flat Washer, 5/8″ Outside Diameter (100 Pack)
Where to find 0.25-inch nuts:
- Home Depot: Everbilt 1/4 in.-20 Zinc Plated Hex Nut (100-Pack)
- Amazon: Powlankou 100 Pieces 1/4″-20 Stainless Hex Nut, Stainless Steel (304) 18-8 Nuts
- Walmart: Uxcell 1/4″-20 Zinc Plated Hexagon Lock Mechanical Nuts Silver Tone (100-pack)
Drill bits
Use drill bits 0.25 inches or, ideally, slightly larger.
10 steps to build a raised garden bed
Once you’ve gathered your tools and materials, let’s jump into creating your raised bed for flowers and veggies.
Step 1: Cut the boards
Determine the length you want your raised garden box to be. Later in this article, we cover how many boards you’ll need and how to cut them for raised garden beds of different sizes.
Since this tutorial is about how to build a box 4’ x 8’ x 1’, purchase six 2′ x 6′ x 8’ boards. Have the store cut two of them to 4 feet. Or, if you have access to a circular saw, table saw, or miter saw, you can cut the boards yourself. For your safety, don’t attempt to operate a saw if you’ve never done it before.
Select straight boards that are not damaged. Avoid boards with cracks and chips. Make sure the boards are as thick as possible, at least 2 inches thick. Thin boards do not last long in raised garden beds.
Step 2: Check the size of the framing angles
Use framing angles that are 12 inches. Make sure the framing angles are long enough to connect the boards. Lay two boards next to each other and place the angle across the two boards to make sure it fits across them.
Step 3: Measure the thickness of the planks
Lumber is usually thinner than the size retail stores indicate. So, your next step is to measure the thickness of the boards. Mark that thickness on both ends of each of the boards to establish a straight guideline. This is where the end of each board will rest against that of the other board. It is also where the framing angle will be placed on the 4-foot boards. The side with the line drawn across will be the inside of the bed.
Step 4: Drill holes in 4-foot boards
Line up the 4-foot boards, two boards at a time. Place the edge of the framing angle across the two boards and on the line you drew, and mark the number of holes you want. The holes will be used to connect the boards. So, the number of holes you mark will match how many screws you want to use to secure the boards together.
Remember, you will have to have enough hex screws, washers, and nuts for each hole. Make sure each board has at least one hole.
Measure your marks a few times so that everything will line up perfectly when you drill. When you are confident in your measurements, drill a hole in each place you marked.
Step 5: Connect 4-foot boards with framing angles
Lay two of the 4-foot boards side by side again so that one framing angle goes across the two boards. Place the framing angle on the two boards, with the edge of the framing angle along the line you drew.
After lining up the framing angle with the boards, attach the framing angle to the ends of the boards with the hex screws, washers, and nuts. The hex screws should be on the outside. The washers and nuts go on the inside.
Lay the other two 4-foot boards side by side and repeat these steps. You will have two pairs of 4-foot boards with framing angles at the ends. These are the walls or sides that make up the width of your bed.
Step 6: Drill holes in 8-foot boards
Place two of the 8-foot boards flush against the framing angle that you just attached to the 4-foot boards. These boards will extend into the air or be perpendicular (vertical) to one of the sides you just built.
Mark holes on the two boards that are vertical. The holes must match up with the holes in the framing angle. You may have to do one board at a time if you don’t have anyone to hold the boards for you as you mark the holes.
Remove the vertical boards and drill the holes in the places you marked.
Step 7: Connect boards to make a corner
Connect each of the two 8-foot boards to the framing angle with the screws, washers, and nuts. One corner of your garden box is now assembled.
Step 8: Repeat for second corner
Repeat steps 6 and 7 on the other end of the garden bed wall. The structure will look like the letter “U.” You now have two corners of your raised garden bed assembled.
Use a framing square to ensure the corners are both at a 90-degree angle.
Step 9: Attach the last side
Lay the U-shaped structure down so that you can attach the final wall to complete your raised garden box.
Slide in the other 4-foot wall so it lines up with the long 8-foot wood boards. Mark holes in the boards that line up with the holes in the long boards. Drill where indicated. Connect the final wall to the long wood boards with the screws, washers, and nuts.
Voila! You now have a rectangular raised garden bed completely assembled.
Step 10: Tighten the bolts
If the raised garden bed is up to your standards and you’re ready to put it to use, grab a bolt tightener and tighten each bolt.
If you didn’t build the box in its final resting place, move it to the desired location. You are now the builder and owner of your very own raised garden bed.
Easier ways to connect boards
Raised bed corners or planter blocks: There are some things you can do to make your build easier. Homeowners can buy raised bed corners instead of framing angles for an easy way to attach the boards and make the corners. Most raised bed corners fit a standard 2-inch thick board. Check the thickness of the corners to be sure. You can also use planter blocks.
Screws without framing angles: The boards can also be attached with screws without using framing angles. While this type of build is similar to what is discussed in the steps above, there are differences in the process and materials used.
This is a method you can use when making a raised garden bed with a height of only 6 inches, so it is only one board high. You will not stack two boards to create a depth of 1 foot with this method. Following are a few more differences between the method described in detail above and the method that doesn’t use framing angles. Adjust the steps above as necessary if using this method.
The type of supplies will differ, like the type of screws used and the size of the drill bits, for example. Two holes are drilled into the end of each plank. Each board will overlap the end of the board it is being connected to, so the holes must line up. Deck screws are used to connect the boards. You will more than likely need another pair of hands to hold the boards steady as you put in the screws.
This method allows for more human error, as it is more difficult to make sure the holes line up perfectly so the planks connect correctly.
Thrifty tip: For an even easier and more affordable build, you can recycle materials like plastic crates or even wooden bookshelves. Check out these DIY raised garden bed ideas to learn more and get inspired to reduce, reuse, and recycle!
Preparing the location for your raised garden bed
Once you’ve built the actual structure of the raised garden bed, you have to prepare a place for it to ensure successful plantings. Here’s what you need to do to prepare a spot for your raised bed:
- Choose a good location: Choose a spot where the plants can get six to eight hours of full sunlight a day.
- Level the ground: Place your bed on even, level ground. If your desired area is not level, dig up the soil to lower high spots or add more soil to elevate low spots until the area is level. Make sure the slope allows the soil to drain well.
- Line the bottom of the bed with hardware cloth or landscape fabric: Landscape fabric is a barrier between the soil you add to the bed and the ground. It keeps weeds and grass from sprouting in the bed. It also allows water to flow through and drain. Landscape fabric pegs or staples can be used to secure the weed barrier.
Adding the soil and seeds
You’re now ready to fill your bed with the soil you desire and add any necessary soil amendments for better plant health. First, you have to figure out how much soil you’ll need to fill your bed.
To get the volume of your raised bed in cubic feet, all measurements should be in the same unit. Use this formula to know how much soil to add:
Volume = Length X Width X Height
The volume for a raised bed with dimensions of 4 feet x 8 feet x 1 foot is 32 cubic feet. So, the raised garden bed in this tutorial requires 32 cubic feet of soil.
Buy a little more soil than what is needed to compensate for the soil settling and future top-offs.
Mix your topsoil correctly
Soil with lots of organic matter is best. For optimal results, put a mixture of compost and topsoil in your bed. Find out what the specific types of plants you’re growing need in soil – i.e. if they need loose or dense soil, which plant nutrients they need more of, and what soil pH they prefer. You can add soil amendments to the topsoil in your bed to meet these specific needs.
Different plants require different ratios of compost:soil. However, the best combination for vegetable gardens is typically about:
- 30% compost
- 60% topsoil
- 10% potting mix
You can make your own compost or buy it from any garden store. You can also purchase topsoil online or at your local garden soil. Topsoil costs about $10 – $50 per cubic yard. For our 32-cubic-foot (about 1.2-cubic-yard) bed, topsoil would cost about $12 – $60, depending on the quality of the soil and where we bought it.
Add the soil all the way to the top of your raised garden bed. The soil will settle. Top it off with compost if necessary.
More compost will be needed at the end of the growing season (fall or winter).
Plant seeds
Once your soil is prepped, plant your seeds with enough space between them to grow. If taller plants are in the same beds as shorter plants, arrange them so taller plants do not block the sunlight. As some plants grow, they may need to be supported with tomato cages, plant stakes, or trellises. You may want to use bird netting to keep critters from feasting on your plants.
Once your fruits, veggies, and flowers are planted, lay down mulch to suppress weeds and retain moisture. If you use grass clippings, be sure the grass has not been treated with any chemicals, like weed and feed and other herbicides.
Different sizes of garden beds
Now that you know how to build a DIY raised garden bed that is 4’ x 8’ x 1’, you can modify it to build other sizes. You can build several boxes. Multiple short boxes allow homeowners to plant crop families in their own boxes. Here are some different sizes and modifications you might consider:
- 4 feet x 4 feet x 1 foot: This garden box will be square since the width and length (long sides) will all be 4 feet. For a bed of this size, purchase four 2” x 6” x 8’ boards. Have the store cut the four boards in half (or do it yourself). Use angles that are 10 inches long.
- 2 feet x 6 feet x 1 foot: This size is ideal for a narrow garden space. To get this size, purchase four 2” x 6” x 8’ boards. Have 2 feet cut off each board. This gives you four boards of 2 feet long for the width of your garden bed wall and four boards of 6 feet long for the long side of your garden bed. Select framing angles that are 12 inches.
- 4 feet x 4 feet x 6 inches: If you’re sure you don’t need the extra depth because you’re only planting shallow-rooted crops, like radishes and cilantro, this is an ideal size. Buy two 2” x 6” x 8’ boards. Have each board cut to 4 feet. You’re not stacking the two boards, so you only need 4-inch framing angles. Use 16 to 24 1-inch hex screws.
Health and safety tip: Avoid pressure-treated lumber
When wood comes in contact with the ground or high moisture, it can deteriorate. Pressure-treated wood has gone through a process where the wood has been treated with preservative chemicals so it lasts longer. However, the chemicals from CCA-treated wood and other pressure-treated wood can leach into your soil, fruits, and veggies.
CCA stands for chromated copper arsenated. The EPA has restricted the use of CCA-treated wood due to the risks of exposure to chemicals like arsenic. Fortunately, wood treated with any preservatives containing arsenic was to be phased out by the end of 2003. Therefore, pressure-treated wood found in home centers will more than likely not be CCA-treated.
They are more likely to be ACQ-treated or treated with another chemical. ACQ is alkaline copper quaternary ammonia. It has no chromium, arsenic, or chemicals the EPA considers toxic. However, it does have more copper than CCA, and some of the copper will leach from ACQ-treated wood into your soil.
Untreated wood is your best bet. It is your choice, of course. But if you are going through all the trouble of growing your own fruits and veggies to be healthier, why expose yourself to any unnecessary chemicals? Untreated wood may not last as long as wood treated with CCA or other chemicals, but it’s safer for growing edible plants.
Here are some examples of wood that are naturally decay-resistant:
- Redwood
- Western or eastern red cedar
- White oak
- Northern white cedar
FAQ about building raised garden beds
What fruits and veggies can grow in a bed with a depth of 6 inches?
Some shallow-rooted crops that only need 6 inches of soil include:
- Spinach
- Strawberries
- Dill
- Parsley
- Basil
- Oregano
What fruits and veggies need a depth of 12 inches to grow?
Everything that grows well in a 6-inch soil depth can also grow in soil depths greater than 6 inches. As a rule, anything that needs a minimum soil depth can grow in that amount or greater. So, if you’re not sure what you want to grow, it’s best to make sure you have a total of 12 to 18 inches of soil depth. Here are some edibles that require at least 12 inches of soil depth:
- Cucumbers
- Kale
- Beets
- Carrots
- Garlic
- Cauliflower
What are some edibles that need 18 inches of soil depth?
Some plants have deep root systems and need at least 18 inches of soil, including the following:
- Watermelon
- Tomatoes
- Eggplant
- Peppers
Which cedar raised garden bed is the cheapest to build?
A smaller box will cost less because it uses less materials. A 4’ x 4’ x 6” garden bed would be cheaper than a 4’ x 4’ x 1’, or the other sizes discussed in this article.
Keep in mind that cost depends on several factors, like the type of raised garden bed materials used. Building a garden bed with pine is cheaper, but not recommended because it will not last long. Cedar is more expensive but will give you more bang for your buck because it is insect and rot-resistant, durable, and long-lasting.
When to look for landscaping help
You are now all set to start your vegetable garden. Who knows? You may become your neighborhood’s local farmer. If not, you’ll at least enjoy the peace of mind of knowing exactly what you’re eating – and exactly how it was grown.
And if you ever need help growing delicious fruits and veggies for your family and friends, Lawn Love has your back! In minutes, you can connect with licensed and insured gardening services in your area, either online or on the phone with our friendly, helpful customer service team.
Main Photo Credit: AnnaGreen / Canva Pro / License
