A raised bed garden provides a versatile and attractive option for gardeners planning their next crop of veggies or show-stopping flowers.
Whether you’re tight on space or want to cultivate specific soil qualities, read on to learn how making a raised garden bed can (literally) elevate your gardening.
Raised Bed Garden Ideas
You can get creative when it comes to raised beds as long as your design allows for proper drainage and doesn’t include any harmful materials that could leach into the soil. Which can end up getting into the plants that you are consuming.
Stone Raised Beds
If you want a raised garden bed that will last a lifetime, use stone or brick. As these materials can withstand moisture without rotting like wood.
Cinder blocks also make quick and easy raised beds that will be long-lasting.
Wood Raised Beds
Wood is the most commonly used material for raised bed gardening. It is simple to use and easy to construct. And if you allow for proper drainage and select a rot-resistant species like Cedar, it could last quite a while.
Avoid treated wood such as CCA-treated wood, as the chemicals can leach into the soil.
The video below is an excellent overview of wooden raised beds, including drip irrigation, pathways, and lighting.
Galvanized Metal
Galvanized metal can also be used for raised beds. Very simple to make and super durable.
This woman used metal window wells to create raised beds by bolting two of them together.
This next video combines wood and steel. Also, showing you step-by-step how to make it.
Types of Raised Bed Gardens
Defined as a mound of soil raised above the surrounding ground, the term ‘raised garden bed’ can refer to several types of beds.
Raised Ground Beds
Raised ground beds, sometimes referred to as “built-in raised beds,” do not use supportive frames to contain the soil. Instead, they are simply mounds of soil higher than the surrounding ground (typically 6-8 inches higher) with a flat top.
Since raised ground beds don’t require a frame, they are the simplest and cheapest type of bed if you’re planning on creating your own bed. That being said, raised ground beds require a larger planting area and are the least versatile option.
Supported Raised Beds
Supported raised beds take the concept of a raised ground bed but surround the mound of soil with a supportive edge or frame.
If you’re trying to garden on sloped or uneven ground, this type of bed will allow you to build a flat-topped surface for planting without having to re-landscape your entire backyard.
Containerized Raised Beds
Containerized raised beds are the most versatile type of raised bed. As the name suggests, these beds are essentially containers for soil, including large planters and plots.
You can place containerized raised beds anywhere outside regardless of soil quality (or even the preexistence of soil, for that matter). So long as you consider weight when placing these containers, containerized raised beds can sit on your deck, patio, or porch, as well as on your backyard.
Benefits
The major benefit of raised bed gardens is controlling soil quality. If you’re gardening in an urban space without any soil, raised garden beds provide a container to pour nutrient-rich soil into. Or, if you’re situated in a landscape with poor soil quality, you can similarly acquire better soil than that naturally available to you in the ground.
Plus, if you’re able to create multiple, separate raised garden beds, you can pour a different type of soil into each container, matching soil to the plants you want to grow rather than adjusting your crop plan to fit the soil.
Additionally, since raised beds are in fact raised from the ground, the soil warms up earlier in the spring allowing for earlier planting.
Some raised garden beds include a plastic screen at the bottom. This will help keep out gophers and weeds alike! A plastic screen can also prevent weed growth (but you want to be careful not to interfere with the bed’s drainage).
Based on the structure you’re using and how high the soil is, raised garden beds can eliminate some degree of bending over.
Raised garden beds also offer many aesthetic benefits. Supportive edges or frames help keep soil in place, meaning soil stays off of pathways. In addition to keeping your garden neat and tidy, these frames also help prevent erosion.
Disadvantages
The major disadvantage of raised bed gardens relates to cost. Whether you build your frame or purchase a pre-built garden bed, these materials add up, not to mention the cost of buying enough soil to fill these garden beds. (The transport associated with these materials also means that raised garden beds are less sustainable.)
Even if cost is not a determining factor for you, you’ll still want to consider the additional maintenance required for raised garden beds. Soil dries out faster in the summer, meaning you will have to water your beds more frequently.Or, install an automatic watering system like drip irragation.
Since the beds are removed from the surrounding ground, the soil cools down more quickly in the fall and gets colder throughout the winter. This means that any perennials planted in these beds will need hardy varieties.
How to Make & Fill a Raised Garden Bed
Building your own raised garden beds is the best way to ensure your bed will meet the exact specifications of your dream garden. Plus, it’s not too difficult if you follow a plan. Consider the following steps if you’re thinking about building a raised garden bed.
How to Make & Fill a Raised Garden Bed
Step 1: Identify a Location
Make sure you have the appropriate location for your bed before you do anything else. Choose a location that receives at least 6-8 hours of full sun. If you’re building a built-in raised bed, avoid wet or marshy areas as this type of ground could contribute to root rot.
After you have assessed your space, determine the length, width, and height of your raised bed(s). Hint: make sure you can access all of the garden without stepping on it, as this would negatively compact the soil.
Step 2: Gather Materials
You can build the frame of your bed using a variety of materials. Wood, stone, brick, and cement blocks are popular options.
Pine will likely be the cheapest option if you want a wooden frame; however, it will rot after a few years. Boards from cedar, redwood, or locust will be more expensive but last longer than cheaper wood. Cedar, in particular, should last 10-15 years; plus, the oils in the wood naturally repel insects.
Concrete will not rot, but it might increase soil pH over time. Be aware that cinder blocks gather heat. Use this trait to your advantage if you’re thinking about planting Mediterranean-type herbs!
Whichever material you choose, make sure the frame won’t leach chemicals into your soil.
Step 3: Prepare the Site
You’ll need to prepare the ground if you’re building either a built-in raised bed or a supported raised bed.
First, create an outline for your bed-to-be using a long piece of string. Within this outline, you can choose to dig out the preexisting turf and loosen the soil you’ve uncovered, or cover the space with a layer of newspaper or cardboard (free from anything that won’t decompose) followed by a layer of compost.
Whether you choose the dig or no-dig method, make sure the ground is level.
Step 4: Install the Frame
If you’re building a supported raised bed, dig a trench around the perimeter of your bed and then bury a bit of the bottom to stabilize the bed frames.Or, you can pile up some soil on the outside of the frame at ground level.
For a containerized raised garden bed, screw the sides together using decking screws. You should also attach the bottom and any legs at this point.
If you’re not inclined toward garden DIY, don’t worry! You can easily find pre-built raised garden beds available online and in stores.
Step 5: Fill with Soil
Fill your frame with approximately 40% compost, 40% topsoil, and 20% aeration. Aeration is essential for allowing oxygen into the soil that bacteria and roots thrive on. Some examples would be lava rock, perlite, and pumice.
If in doubt, the more organic matter, the better. Once you’ve mixed these soil ingredients, plant your seedlings!
What to Plant
Historically, growers divided raised beds by specific functions, such as kitchen bed (edible plants), nursery bed (a plot for growing seedlings), and flower bed (flowering plants).
If you’re creating a garden out of many raised beds, another way of organizing the plants is to assign a single plant variety to each bed. But suppose you’re working with fewer raised beds. In that case, it’s certainly possible to plant a variety of vegetables or flowers in the same bed – be sure to consider which plants appreciate similar growing conditions.
Soil Depth in Raised Bed Gardening
Soil depth also determines which plants will grow best in your raised beds. As a rule of thumb, raised garden beds should have a minimum soil depth of 6 inches. But the deeper your soil, the more types of plants you can plant.
With a minimum of 6 inches of soil, you can grow many shallow-rooted crops such as lettuce, salad greens, spinach, onions, leeks, radishes, strawberries, and certain herbs (basil, chives, cilantro, dill, mint, oregano, parsley, thyme). Annual flowers such as marigolds will also grow well here.
If your raised garden bed is at least 12 inches deep, you can grow vegetables like carrots, beans, beets, turnips, summer squash, broccoli, cabbage, Brussels sprouts, cauliflower, kale, swiss chard, and cucumbers as well as cantaloupes. You can also plant woodier herbs such as rosemary, lavender, and sage at this depth.
In addition to the plants that will grow at 6 and 12 inches, if you have 18+ inches of soil, you can plant eggplant, okra, peppers, pumpkins, sweet potatoes, tomatoes, and watermelon in your raised garden bed.
As you’re planting, don’t forget to also consider the space between seedlings.
Grow Tall by Going Vertical
One advantage of raised bed gardening is going vertical and horizontal. By adding vertical layers, you can increase your garden’s number of square feet. Which can help get the maximum yield out of the same space.
Final Thoughts
The practice of using raised garden beds has been around for centuries. From Native Americans who created raised mounds of organic matter rather than tilling bare rows of earth to medieval farmers who edged their garden beds with wattle fences, gardeners have long used this technique to grow plentiful crops.
Why not see for yourself how raised garden beds can take your garden to the next level?
Frequently Asked Questions
What do you put in the bottom of a raised garden bed?
Ideally, you want to fill the bottom with sticks and small logs. This will promote aeration, decompose over time, release nutrients, and retain moisture. This will also reduce the amount of soil needed which will help keep costs down.
Should I put rocks in the bottom of my raised garden bed?
No, you don’t need to put stone in the bottom of your raised bed. You’re better off with organic material as answered above.
Should I put cardboard under my raised garden bed?
Yes, cardboard is excellent for suppressing weeds. It will decompose over time.
Can I put a raised bed on top of grass?
Yes, you can place it on top of the grass. Just be sure to include a layer of cardboard. The expert on this is Charles Dowding. He is well-known for promoting what he calls “no-dig” gardening. Which is essentially just laying down cardboard on top of the grass, then layering compost on top of the cardboard.
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Sources
Soil to Fill Raised Garden Beds: extension.umd.edu/resource/soil-fill-raised-beds
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Davin Eberhardt
Website | + posts
Davin is a jack-of-all-trades but has professional training and experience in various home and garden subjects. He leans on other experts when needed and edits and fact-checks all articles.
