The Best Height for a Raised Garden Bed Depends on What You Plan to Grow

How tall should your raised beds be? I get asked this question all the time, and the answer is... It depends! First, it depends on the type of plants you want to have and how deep their roots grow. After that, it depends on your priorities in the garden, whether those include saving money, increasing the ease of tending your plants, or making your garden as beautiful as possible.

Here's a quick overview of the best raised bed height based on plant types:

• Leafy greens and herbs: 6 to 12 inches
• Root crops: 12 inches
• Fruiting plants: 12 to 18 inches

A 12-inch raised bed is a great minimum height for growing lots of delicious plants in the kitchen garden. If you want to grow larger vining plants like tomatoes, squash, or zucchini—plants that sprawl and tend to draw a lot of nutrients from the soil as they grow—you might move closer to an 18-inch raised bed.

Let's look more closely at the different heights I recommend for growing herbs, salad greens, root crops, and other fruits and veggies, before exploring some other considerations to keep in mind when determining which raised bed height is best for you and your garden.

How deep does a raised bed need to be for herbs?

Many of the herbs you might want to grow in your garden have shallow root systems that only need about 6 inches of raised bed or container depth. These herbs include oregano, rosemary, mint, sage, basil, and thyme. These herbs are ideal for growing in pots and containers, which isn't to say that you can't also plant them in deeper raised beds.

The exception here would be herbs in the carrot family. Cilantro, parsley, and dill actually grow a little taproot like a carrot. They prefer more space to dig their roots down and do better in a container or raised bed that's at least 12 inches tall.

(Learn more about growing herbs in containers.)

How tall should a raised garden bed be for leafy greens?

A 6-inch raised bed is perfectly fine for smaller leafy greens like lettuce plants, arugula, and spinach. If you would like to grow romaine or other heading lettuces, Swiss chard, or smaller varieties of kale, I recommend having a raised beds that's at least 12 inches deep.

Like herbs, leafy greens are great options for growing in containers if you don't have raised beds set up yet. One thing to just keep in mind with shallower raised beds or containers is that they will dry out faster than a deeper raised bed, which means you should keep an eye on the moisture level and be ready to water.

(Learn more about growing leafy greens in a container.)

How deep does a raised bed need to be for carrots?

Twelve inches is a great height for most root crops, including radishes, beets, and carrots. This is assuming you're not trying to grow the world's longest carrot, of course.

Root crops are very sensitive to what's in the soil around them, so even if you're not expecting radishes to grow longer than an inch, they still like to have plenty of loose soil beneath them so they can form that nice, juicy taproot. You can grow root crops in pots, containers, or grow bags as long as they're at least 12 inches deep.

How deep does a raised bed need to be for peppers?

Even though peppers are fruiting plants, they typically don't need quite as much room below the soil as tomatoes or eggplants do. A 12-inch-deep raised bed should be great for peppers.

How deep should a raised bed be for tomatoes?

Tomatoes are heavy feeders, and indeterminate tomatoes, or the vining type, either spread out horizontally or climb as they produce fruit. All that means that their roots need lots of soil depth to find nutrients and build support structures for the heavy plant.

Tomatoes should ideally be grown in a raised bed that's at least 15 to 18 inches deep. Many of my clients in Houston are successfully growing tomatoes in 12-inch deep raised garden beds, but their plants tend to be a little stunted compared to plants in deeper beds.

In my first ever attempt to grow tomatoes, I planted them in a 6-inch raised bed. The only reason the plants grew is because their roots were able to push into the native soil beneath the bed (even though it was heavy in clay and not ideal for a vegetable garden). I never ended up getting much fruit from these plants.

How deep should a raised bed be for cucumbers?

Cucumbers, squash, and zucchini, like tomatoes, are larger plants that need 15 to 18 inches of soil to push into. Just think of how heavy a large cucumber is. You can imagine the kind of root structure needed to support a plant baring fruit that heavy!

In addition to your raised beds, I recommend having a trellis for your cucumbers to climb up. This will keep your plants overall happier and healthier.

How deep should a raised bed be for potatoes?

Potatoes spread underground while they send up leafy growth above ground that takes up quite a good deal of space. You can grow potatoes in raised beds that are at least 12 inches tall, but I actually recommend growing potatoes outside of a raised garden bed, right in the ground. No need to worry about grow bags, containers, or pots.

The Ideal Raised Bed Height for Productivity Is 16 to 18 Inches

If you want to be able to grow everything from a small lettuce plant to a large squash plant in your raised bed, I recommend going with a height between 16 and 18 inches. This is really the maximum height you need for almost any kind of annual plant you're going to grow in a vegetable garden. In other words, you can plant just about anything you want inside those raised beds.

It's only if you plan on growing deeper-rooted perennials like maybe berries or asparagus that you might consider a 20- to 24-inch-deep bed for better productivity.

4 Other Factors to Consider for the Height of a Raised Bed

So far, we've only discussed how tall a raised bed should be based on the type of plants you might want to grow, with the goal of maximizing your productivity. You might also keep other priorities in mind, including accessibility, beauty, expense, and critter control.

One: Accessibility

Ease of planting and tending your garden is extremely important. In fact, it's one of my main points for gardening in raised beds in the first place. While few kitchen garden plants need more than 15 to 18 inches for their roots, you might find that working in a 2-foot-tall raised bed is more comfortable or accessible. This is especially true if you have back or knee problems or any kind of mobility limitation. I've had a couple of clients in wheelchairs who even prefer 3-foot-tall raised beds for greater accessibility.

The first raised beds I installed for clients were 12-inches tall. Once one client requested a 2-foot-tall bed, I noticed almost all my clients began requesting this added height. I ended up installing 2-foot-tall beds for myself in my next garden, and I quickly grew to appreciate not having to lean down or squat as much.

Two: Aesthetic Appeal

Beyond greater productivity and ease of use, a taller raised bed might look better in your space. I often have clients who choose the height of their raised beds based on the height of an existing structure (a fire pit, a deck, etc.) around their home or landscape they want to line up with.

Many clients feel that two feet of raised bed material like stone, Corten steel, or cedar is able to show off the beauty of the material better than anything shorter. I personally feel that once you get closer to 3-feet-tall beds, however, the beds are too tall to be aesthetically appealing.

Three: Expense

An increase in height means an increase in not just building materials for the raised bed, but also soil to fill it. Going from a 12-inch-tall raised bed to a 24-inch raised bed made out of cedar, for example, will essentially double your material cost.

Four: Critter Control

No height of raised bed accessible to humans will be sufficiently tall enough to keep out squirrels, deer, and birds, but critters of the household variety can be deterred by 3-foot-tall raised beds. I'm speaking of dogs (and the occasional pet chickens). I've had many a client whose dog can easily jump 2 feet and needs to be kept out of the garden bed. Three feet is enough to ensure your dog can't hop in and dig up your tomatoes.

How high should a raised garden bed be to keep rabbits out?

I once had a mother rabbit burrow into my raised beds and try to raise her young. Clearly, 12 inches was not sufficient to deter her one bit.

If bunnies are an issue in your area, I recommend raised beds that are 24 inches tall or more. Even if your beds are 2 feet tall, I recommend using another barrier like garden mesh spread over your entire bed to keep rabbits out. If your beds are 3 feet tall, rabbits should no longer be able to access your veggies.

You Decide the Best Height for Your Raised Beds Based on Your Desired Productivity and Other Priorities

So when you're choosing the ideal height for your raised bed, first prioritize the plants you want to grow to come up with a minimum height. Once you've decided what you'll be growing, consider your other priorities and which height works best for you and your garden.

I hope this has enlightened you and given you a bit more information on how to design your own raised-bed kitchen garden. I encourage you to check out our other articles on raised beds to learn more about how to maximize what you can grow in your kitchen garden! Thanks for being here!