Raised garden beds are fairly easy to construct, even easier to maintain, and offer myriad benefits for your garden (and you)! Here’s how to build a raised garden bed in your backyard, as well as some advice on using the right wood and soil.
Raised beds are an easy way to get into gardening! Whether you purchase a kit or build your own, there are many great reasons for using raised bed gardening.
What is a Raised Garden Bed?
A raised garden bed (or simply “raised bed”) is a large planting container that sits aboveground and is filled with soil and plants. It is a box with no bottom or top—a frame, really—that is placed in a sunny spot and filled with good-quality soil—to become a source of pride and pleasure, and a centerpiece of the garden.
Why Should I Build a Raised Garden Bed?
Raised beds have many benefits. Here are a few reasons why you should consider using one:
- Garden chores are made easier and more comfortable thanks to less bending and kneeling. Save your knees and back from the strain and pain of tending the garden!
- Productivity of plants is improved due to better drainage and deeper rooting.
- Raised beds are ideal for small spaces where a conventional row garden might be too wild and unwieldy. Raised beds help to keep things organized and in check.
- Planting in a raised bed gives you full control over soil quality and content, which is especially important in areas where the existing soil is rocky, nutrient-poor, or riddled with weeds.
- Raised beds allow for a longer growing season, since you can work the soil more quickly in the spring in frost-hardened regions, or convert the bed into a cold frame in the fall.
- Fewer weeds are seen in raised beds thanks to the bed being elevated away from surrounding weeds and being filled with disease- and weed-free soil.
- Raised beds allow for easier square-foot gardening and companion planting.
Learn more about the benefits of raised garden beds.
Choosing the Right Wood for Raised Beds
Many people are concerned about the safety of their wood frame. First, rest assured that CCA pressure-treated wood is banned, as it was known to leach arsenic. To ensure that the wood lasts, there are several options:
- Regular pressure-treated lumber sold today has a mixture of chemicals applied to prevent the moist soil and weather from rotting it. Although pressure-treated wood is certified as safe for organic growing, some people have reservations about using it, and there are various eco-friendly alternatives.
- More expensive woods, such as cedar, contain natural oils which prevent rotting and make them much more durable. They are more expensive to buy, but they will last many more years.
- Choosing thicker boards can make the wood last longer. For example, 2-inch-thick locally sourced larch should last 10 years, even without treatment.
- Avoid using railroad ties, as they may be treated with creosote, which is toxic.
Alternatives to wood include concrete blocks or bricks. However, keep in mind that concrete will increase the soil pH over time, and you will have to amend the soil accordingly to grow your best garden.
How Big Should Your Raised Bed Be?
- First, you need a location that has level ground and gets the right amount of sunlight (6 to 8 hours per day). This should narrow down your options a bit.
- In terms of bed size, 4 feet is a common width. Lumber is often cut in 4-foot increments, and you also want to be able to access the garden without stepping into the bed. Making the bed too wide will make it difficult to reach the middle, which makes weeding and harvesting a pain.
- Length isn’t as important. Typical plots are often 4 feet wide by 8 feet long or 4 feet wide by 12 feet long. Make your bed as long as you like or build multiple raised beds for different crops.
- The depth of the bed can vary, but 6 inches of soil should be the minimum. Most garden plants need at least 6 to 12 inches for their roots, so 12 inches is ideal.
Preparing the Site for a Raised Bed
- Before you establish the bed, break up and loosen the soil underneath with a garden fork so that it’s not compacted. Go about 6 to 8 inches deep. For improved rooting, some gardeners like to remove the top layer (about a spade’s depth), dig down another layer, and then return the top layer and mix the soil layers together.
- If you’re planning to put your raised bed in a space currently occupied by a lawn, lay down a sheet of cardboard, a tarp, or a piece of landscaping fabric to kill off the grass first. After about six weeks (or less, depending on the weather), the grass should be dead and will be much easier to remove.
Building a Raised Garden Bed
- To support timber beds, place wooden stakes at every corner (and every few feet for longer beds). Place on the inside of the bed so that the stakes are less visible.
- Drive the stakes about 60% (2 feet) into the ground and leave the rest of the stakes exposed aboveground.
- Ensure that the stakes are level so that they’re in the ground at the same height, or you’ll have uneven beds.
- Set the lowest boards a couple inches below ground level. Check that they are level.
- Use galvanized nails (or screws) to fix the boards to the stakes.
- Add any additional rows of boards, fixing them to the stakes, too.
Check out our video on how to build raised beds for your vegetables:
Soil for Raised Garden Beds
The soil blend that you put into your raised bed is its most important ingredient. More gardens fail or falter due to poor soil than almost anything else.
- Fill the beds with a mix of topsoil, compost, and other organic material, such as manure, to give your plants a nutrient-rich environment (see recipes below). Learn more about soil amendments and preparing soil for planting.
- Note that the soil in a raised bed will dry out more quickly. During the spring and fall, this is fine, but during the summer, add straw, mulch, or hay on top of the soil to help it retain moisture.
- Frequent watering will be critical with raised beds, especially in the early stages of plant growth. Otherwise, raised beds need little maintenance.
Raised Bed Soil Recipe
For a 4x8-foot raised bed:
- 4 bags (2 cubic feet each) topsoil (Note: Avoid using topsoil from your yard, as it may contain weeds and pests.)
- 2 pails (3 cubic feet each) peat moss
- 2 bags (2–3 cubic feet each) compost or composted cow manure
- 2-inch layer of shredded leaves or grass clippings (grass clippings should be herbicide- and fertilizer-free)
Makes enough for a depth of about 9 inches.
Square-foot gardening in a raised bed. Photo by Oregon State University/Wikimedia Commons.
Planning a Raised Bed Garden
To plan out the perfect garden for your space, try the Almanac Garden Planner! In minutes, you can create a garden plan right on your computer.
The Garden Planner has a “Raised Garden Bed” feature. It also has a specific square-foot gardening (SFG) feature, which involves dividing the bed into squares to make the organization of your garden a lot simpler (see photo above).
Which ever garden you select, the Garden Planner will show you the number of crops that fit in each space so you don’t waste seed or overcrowd. There’s even a companion planting tool so you plant crops that thrive together and avoid plants that inhibit each other.
Test out our Garden Planner with a free 7-day trial—plenty of time to plan your first garden! If you enjoy the Garden Planner, we hope you’ll subscribe. Otherwise, this is ample time to play around and give it a go!
- Get more tips on building a raised garden bed and planning for it.
- If this article sparks your interest in raised beds, then we’ll show you how to do it. See our video, “How to Use Raised Beds in Your Garden.”
- Learn more about companion planting, which can vastly improve the health and yield of your garden. See our Companion Planting Guide and our Companion Planting Chart for Vegetables.
- Check out our Plant Growing Guides for advice on growing all of the most popular vegetables, fruit, herbs, and flowers.
Have you ever thought about building your own raised garden bed? Or do you have one already? Tell us about it below!