Raised Beds — The Most Important Element of the Kitchen Garden

As the cost of lumber continues to increase, I get more and more questions about whether raised beds are necessary for a healthy and productive kitchen garden. The extra expense—for the bed materials and then all that soil to fill each one—of a raised bed versus in-ground gardens might seem like, well... a waste.

I get it. But after trying (unsuccessfully) to garden in the ground, I converted to growing most of my edible plants in raised beds and using raised beds in all of my kitchen garden designs for clients.

And let me tell you, unless you're blessed with the perfect soil for growing fruits and vegetables (is anyone?), you'll find that raised beds will drastically increase your productivity and overall success in the kitchen garden, too.

Before setting up your own raised beds, it's important to consider the purpose of gardening in a raised bed, the ideal size of the structure based on your space, and the best materials to use to build your raised bed. Let's look first at the reasons I consider raised beds the most important element of any kitchen garden.

Why We Use Raised Beds for Gardening

Raised beds can increase the productivity and appearance of your kitchen garden space.

The practical purpose of raised beds

• Raised beds allow you to start fresh with healthy soil, rather than amending what you already have (which is probably not ideal for vegetables).
• Raised beds stay warmer than the soil in the ground, which allows you to extend your growing time in the fall and the spring.
• Raised beds give plants' roots more vertical space to dig down so that you can fit more plants horizontally in a tighter space.
• Raised beds drain more quickly than in-ground beds.
• Raised beds increase comfort and ease when tending or harvesting your garden.

The Aesthetic Purpose of Raised Beds

• Raised beds are a beautiful hardscaping piece in their own right, adding beauty to the garden all four seasons, even when nothing is growing.
• Raised beds can make your garden feel like an outdoor room, your own private oasis.

I go into further detail on the reasons raised beds are all around better for gardening here.

The Right Location for Raised Garden Beds

After working with hundreds of clients to design and install kitchen gardens, I've narrowed the long list of things to consider when choosing a site for your raised-bed kitchen garden to four key aspects.

sunlight

The first, and most important, aspect to consider is sunlight exposure. Your garden will need to receive six or more direct sunlight hours per day. Really though, you're aiming for as much sun as possible. Ideally, you'll position your garden on the south side of any tall structures, such as homes, garages, tall sheds, and fences. This is especially important during the winter months, when the sun is lower on the horizon for those of us who live in the Northern Hemisphere.

If your only available spot receives four or so hours of sun a day, you can still have a kitchen garden—you'll just need to prioritize growing herbs and salad greens, plants that will still thrive with less-than-ideal sun. (Read more about how much sun you'll need in your garden.)

water

The second aspect to consider is water proximity. Place your garden, when possible, near a spigot, a rain barrel, or a location where it can be connected to an irrigation system. Plants love the deep and consistent water that drip irrigation can supply (more on the best way to water plants in raised beds in a bit!).

convenience

The third aspect to consider is convenience. Your raised beds should ideally be located as close to the kitchen as possible—or at least as close to your everyday activities as possible. Look for sunny locations near a back door, front door, or even next to your driveway so that you can pop outside with scissors to snip some herbs for dinner or some lettuce leaves for lunch.

aesthetics

Lastly, the final aspect to consider is how your raised beds can fit in with the rest of your landscape. Your garden should feel like an extension of the home, something that's always been there. With that in mind, position your garden near prominent structures or line it up with existing elements of your home or yard. Look for spots where you could add beds along already-established lines, such as a side yard, a fence, a driveway, a deck, a patio, or a pool.

Explore more tips and tricks for choosing the ideal location for your raised beds.

Ideal Raised Garden Beds Dimensions

There are three general parameters for raised bed size: the height, the width, and the length.

The Best Height for Raised Beds

The very first raised bed my family ever put together was only four inches tall, and that height just didn't work for the type of plants we wanted to grow.

A raised bed should be tall enough to accommodate the full root ball of whatever plants you're growing. The minimum raised beds height I ever recommend is six inches, and then there's no reason to go over two feet unless you have a specific reason, such as a mobility issue.

Here is the minimum depth you'll need based on the type of plants you might want to grow:

Keep in mind that beds 18 inches deep or more will have better drainage than shorter beds. While most plants don't need anything deeper than 18 inches, I prefer beds that are two feet deep (24 inches). The extra height is mostly just for the ease and convenience of the gardener. Garden work should be an enjoyable part of your daily routine, not a chore that hurts your knees and back.

I also prefer this height for aesthetic reasons. Two feet of stone, brick, Corten steel, or cedar planks adds beauty and way more vertical interest to a landscape.

Read more on how deep your raised garden beds should be.

The Best Width for Raised Beds

Unlike height, the possible width and length of your raised bed might be limited by the space you have available.

The minimum width I'd recommend for a raised bed is 18 inches. Anything less across just doesn't afford you the full benefits of growing in a raised bed—there wouldn't even be room to plant more than one or two plants across your bed, especially not if they need to spread out. If you can find a space for a bed that's at least two feet wide, that would be preferable.

The maximum width you would want for a raised bed is about four feet wide, and that would only be for beds that you're able to access from all four sides. Anything beyond four and a half to five feet typically makes plants in the middle of the bed too difficult to reach (unless you have very long arms).

If you can only tend from one side because your bed is up against a wall or fence, I’d recommend staying under two and a half feet, which is probably about as far as your arm can reach. 

The Best Length for a Raised Bed

The length of your raised bed will be determined by the space you have available and the materials you'd like to use to build your bed.

If you're using wood to construct your raised beds, eight-foot-long boards are generally the most economic option. That's why many of the raised beds you'll see in our designs just happen to be eight feet in length.

In my experience, the best length for a bed maxes out around 10 to 12 feet long. I've installed beds as long as 25 feet, but we encountered issues with holding the bed structure together as the soil was added. Wooden beds that are too long might start to bow.

Two of Our Most Popular Raised Beds Sizes

One of our most popular raised beds is what I call the $100 raised bed (though, unfortunately, the rising cost of lumber means the materials are going to cost you a bit more than that). This raised garden bed is 4' x 4' x 1' for a total of 16 square feet of growing space. Its height is ideal for growing your favorite herbs and salad greens.

Click on the article below to find step-by-step directions with pictures and a supply list to build your own $100 raised bed. I also include variations to build garden beds that are 2’ x 8’ x 1’, 4' x 4' x 6", 4' x 6' x 1', 4' x 8' x 1', and 2' x 6' x 1'.

The six raised beds in my Chicago kitchen garden (pictured below and featured in my book, Kitchen Garden Revival) each measure 2.5' x 7' x 2'.

You can find the step by step to build my raised beds, complete with top trim, plus a supply list, in our easily downloadable ebook, The Complete Guide to Gardenary Raised Beds.

Learn more about common raised garden bed sizes, including when to go wider versus narrower, here.

The Best Raised Garden Bed Materials

When choosing materials for your raised beds, we prioritize those that are natural, beautiful, durable, sustainable, and also affordable.

Remember, making good decisions when you start to build your raised beds can save you money in the long run and ensure you’re able to enjoy your gardening space to the fullest. I hate seeing people build their first raised beds, only to be disappointed and have to start all over again.

Wood Raised Beds

My favorite wood to use is cedar, which is an incredibly durable timber that will perform well for years to come. Whichever wood you're using, make sure to avoid boards treated with chemicals that could then leach into your soil (and therefore into the food you're going to eat).

If you do want to stain the outside, go with a high-quality, eco-friendly and weather-resistant stain. I get asked a lot of if it's safe to stain or paint the outside of a raised garden bed, so I compiled info about safe stains and paints to use on wooden raised beds. I do recommend using an eco-friendly wood treatment on the inside of your raised beds to prolong the time you can enjoy them in your garden.

When it comes to thickness of your wooden boards for the body of your raised beds, I recommend buying the thickest board you can afford, preferably two inches thick. You'll get more life out of your raised beds and be able to enjoy them for longer if you avoid the temptation of buying something less than one inch thick. (For the trim, boards that are just one-inch thick will work just fine.)

Here are more ways to help your wood raised beds last longer.

Steel Raised Beds

You can't get much more durable than steel, which will quite literally last a lifetime.

My favorite types of steel to use in garden designs are Corten steel, thanks to its weathered look (pictured below), and powder-coated metal, which has a very sleek, modern feel.

Here are three major benefits of using steel, if your budget allows:

• Steel beds have thin sides, and this narrow profile allows you to maximize your growing area.
• Steel is a sustainable resource.
• The soil in a steel garden will warm up faster than a wood bed in the spring.
• Steel is a food-safe material.
• Both corten and powder coated beds can withstand corrosion and won't chip, crack, or peel.
• The color of powder coated beds can be chosen to coordinate with existing materials on your home.

If you're going with steel, make sure you arrange for delivery. I've installed beds that took four (sometimes even five) grown men to carry them off the truck and maneuver them into the yard. Many arrive pre-made, so measure the narrowest part of the path the bed will have to travel to ensure it will fit through.

I love the look and functionality of corten steel so much, I opted for eight of the corten steel raised bed kits for sale in the Gardenary shop (four of the large 4' x 8' beds and four of the small 40" x 40" beds) when it came time to build my new Nashville kitchen garden. Then I added two of the steel containers in large at the entrance. These were easy to put together and install with a partner.

Learn more about corten steel.

rolling raised bed

I have a raised bed I use for my herb garden made out of a steel cattle trough container, which I know to be food-safe. If you're using a cattle trough or a similar stainless steel container, make sure to drill holes in the bottom if there aren't any already so that your raised bed will maintain good drainage.

You can find directions for making your own raised bed on wheels here. This project should cost around $185 if you have or can borrow the necessary tools.

Stone Raised Beds

Nothing beats stone for longevity when it comes to garden materials, no matter what type of temperature ranges, humidity, and water intake your bed will experience. Stone is also food safe and can often be locally sourced. Stone is definitely an investment and might not fit all raised bed budgets. It's on my wish list for a garden someday!

Read more about the pros and cons of stone raised beds.

What to Fill Raised Beds With

Once your garden is fully constructed and installed, it's time to fill your raised bed with the best possible soil to keep your kitchen garden plants happy and healthy.

The main measurement you'll need to calculate for your raised beds is the cubic feet of your garden. To calculate cubic feet, you need to first determine the square feet of your garden. This is simply the length times the width of your garden bed. Then, to get the total cubic feet of each raised bed, simply multiply the square feet of your garden's footprint by the height of your raised bed garden.

This provides the total cubic feet of garden space that must be filled with soil.

If you need less than 27 cubic feet of soil for your raised bed garden, you'll want to purchase soil bags to fill your garden instead of ordering a truck delivery of soil. 

Use our soil calculator to determine how much soil you'll need for your raised beds.

How to Fill Raised Beds

To install the soil—whether you're dumping bags of soil into the bed or carting soil from a huge mound on your driveway—you'll want to slowly fill your raised beds, three to six inches at a time. Be sure to protect your water source (i.e., your drip irrigation, which should already be installed) as you do. Put something like a piece of plastic or cloth on top of the pipe that's coming up to be sure you don't get dirt down into it.

As you install every four to five inches of soil, you want to wet the soil thoroughly so that you can continue to fill it up. This will prevent the level of soil in your bed from suddenly sinking inches overnight. 

Finally, you want to level your soil with a rake.

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

I get asked this question a lot. The answer is new soil.

This is your opportunity to start fresh with clean, nutrient-rich soil and organic matter. I've seen suggestions to add plastic bottles or trash bags as filler to the bottom of raised beds to save money on soil, but that kind of defeats the purpose of giving your plants' roots all the growing room they need. We want to make sure we're filling up our raised beds from the bottom all the way to the top with great organic matter that will feed our plants, not something that will break down slowly and contaminate your soil with plastic particles.

Before you shovel your new soil in, add some simple raised bed liners. If you have an issue with animals that come from underground, such as voles, add some hardware cloth at the bottom of the bed. I recommend weed barrier cloth for everyone to keep weeds out and to prevent your soil from washing out of your bed with the first heavy rain.

Raised Beds Soil Mix

Now that you know how to calculate your soil for your raised beds, it's time to think about what that soil mix should be.

For years, I've used a sandy loam garden soil that's organic, natural, and doesn't include any peat moss products.

If you want more help how to create the soil blend, how to keep your soil healthy, and how to blend a variety of natural soil ingredients to get the best organic mix, grab a copy of my book, Kitchen Garden Revival.

The Best Way to Water Plants in a Raised Bed

I wake up early and use a watering can or hose to soak the soil of my raised beds, but I warn you that watering by hand can get old real fast—plus, it doesn't serve those who frequently travel and can't rely on their gardens consistently receiving one hour of rain water per week.

When watering by hand, avoid spraying the leaves of your plants, and water as close to the soil level as possible so that the water can be absorbed by the roots. I lift the leaves of my big leafy greens out of the way so I can water right at the base of each plant.

This is why I recommend raised beds drip irrigation systems (pictured below) for most of my clients and students. As I mentioned, plants love the deep and consistent water that drip irrigation can supply.

Read more on the best irrigation for raised beds.

Raised Beds Design

When I first started working as a garden consultant, I thought that garden design was just figuring out the best spot to place a wooden box. Now, I know that there are dozens of ways to plot out your kitchen garden space to combine form and function, including our most classic and tested layout options:

• border garden
• L-shaped border garden
• twin gardens
• garden trio
• keyhole garden
• four-garden classics
• formal potager

Explore our ten absolute favorite ways to arrange your raised beds from Gardenary ever.

Raised Bed with Trellis

Something you'll notice in each of those designs is the raised beds all come with trellises. The garden trellis is an essential component of the kitchen garden, and to me, no raised bed is complete without a panel, obelisk, or arch trellis.

The Best Plants to Grow in Raised Garden Beds

Raised beds are the ideal place to grow edible plants like herbs, leafy greens, root crops, and fruit for everyday use. You'll be amazed at how many plants you can fit in each raised bed. Here's why:

Raised beds filled with nutrient-rich soil allow kitchen gardeners to practice something called intensive planting. The idea with intensive planting is to fit a lot of plants into a small space and to add variety into every garden bed by filling it with a mixture of herbs, veggies, and flowers. Just nine square feet of growing space could, for example, contain chives, pansies, radishes, cabbages, Swiss chard, kale, and a sugar snap pea plant growing up a trellis.

The reason we can plant intensively and grow way more plants in a raised bed than we could in the ground is because the raised garden bed provides room for roots to dig down deep, the soil provides the nutrients they need to thrive, and the trellis provides vertical support and encourages larger plants to grow up and stretch out. 

Explore our suggestions for what to plant in your raised beds here.

Raised Beds Are Gardening Game-Changers

Going from an in-ground garden to a raised bed is like the difference between night and day. That's what I've found, that's what all of my Rooted Garden clients have said, and that's even what my mother confessed to me after she gardened in ground for years. We gave her a raised bed kitchen garden for Mother's Day a couple years ago, and she's been singing its praise ever since.

If you're feeling stuck or intimidated over creating your own raised bed kitchen garden, you're not alone. Gardenary exists to give beginner gardeners a place where they can find all the resources they need to keep on growing.

If you're a DIY'er, my book, Kitchen Garden Revival, delves deeper into picking a location for your kitchen garden and then walks you through the planning, designing, and building of your raised beds, plus how to plant and tend your favorite edible plants. You can also find more raised bed DIY ideas here.

If you're more an online-course-type of person, check out our popular course, Kitchen Garden Academy. Over the course of eight modules, we walk you through the complete step by step to set up and grow in your own kitchen garden.

For maximum help setting up your own kitchen garden, find a garden consultant near you to come out to your space.

I'm confident that you're going to love having raised beds if you choose to install them in your outdoor space, and we've got tons of resources to help you build your own gardening haven and start growing!