Raised bed gardens increase in popularity each year. From simple, sustainable structures to elegant, elaborate works of garden art, raised beds run the gamut of styles, sizes, and spending.
While farmers grew crops in the ground for centuries, why is gardening in a raised bed so appealing?
First, raised beds allow you to control the soil. Whether you battle clay soil or you’ve experienced a soil-born disease in your garden, raised beds provide perfect soil conditions. Within the framework of the bed, you control the content and structure of the soil, ensuring a nutrient rich environment for your crops. It’s convenient to test the soil each season, adding the necessary compost or missing nutrients to keep the soil healthy and productive.
With several raised beds dedicated to your kitchen garden, you can easily plan and practice crop rotation. Rotating crops helps maintain soil health and thwarts pests that overwinter in the soil. As newly hatched pests emerge in the spring and find that their food source moved to another bed, they’ll attempt to relocate to the new bed. Fortunately, most pests will die along the way, victim to birds or other predators.
Raised beds allow soil to drain well, avoiding the waterlogged challenges of many in-ground gardens. Irrigation is also easier and less wasteful in the confined space of a raised bed. Properly installed drip irrigation systems target the plants’ roots, ensuring healthy plants, as well as saving money on watering bills.
In the spring, soil in raised beds tends to warm earlier than the ground, allowing you to plant your spring crops sooner. Plus, with the addition of a simple support, you can create low tunnels over your raised beds to extend your season into late fall or winter, depending on your hardiness zone. With the addition of reclaimed windows, you can even create a cold frame for winter growing, using your raised bed as a base.
Raised beds can protect crops from becoming snacks for the wildlife. By reinforcing the bottom of the bed with a barrier, voles and gophers can’t access your tasty root crops, while a row cover can keep the cabbage worms at bay.
By adding vertical supports, you can plant intensely in a raised bed garden, maximizing your growing space. Peas growing on a trellis can be under-planted with lettuce, while growing a border of radishes along the bed’s edge. To maximize your garden output, you might consider Square Foot Gardening, a concept introduced by Mel Bartholomew, which uses a grid to divide the raised bed into square-foot increments. He then shows how many plants can fit into each square: for instance, one eggplant per square foot, 16 carrots per square, two cucumbers, four corn. The grid lays flat atop the raised bed, taking the guesswork out of how many plants you can fit into each bed, helping to maximize the planting and harvest in your space without overcrowding.
Raised beds provide an aesthetically pleasing structure to the garden. Many homeowners wish to grow their own produce, but pesky Homeowners’ Associations frown on untidy gardens. By creating artistically designed raised beds, the crops are contained, edible flowers and pollinator plants can add visual interest, and the raised bed becomes an attractive focal point in the garden. Construct several beds, place them at equal intervals or in a potager-inspired design, add stone paths and an arbor, and suddenly you have a beautiful edible garden worthy of a magazine photo shoot.
From saving a bit of back ache to controlling the composition of your soil, raised beds provide many benefits in the garden.
Types of Raised Beds:
While there are a wide variety of styles and materials that can be used to create raised beds—hugelculture, reclaimed wood, bricks, fallen logs, straw bales, even concrete blocks—the most prevalent style of raised bed is easily built from lumber. Armed with a measuring tape, drill, and level, constructing a raised bed is fast and easy, even for those of us not known for our dexterity with drills.
Before You Begin:
Proper planning will save you time and money when creating your raised bed garden. First, consider what types of crops you want to grow. Are you looking to grow a few tomato plants each summer, or do you intend to feed a family of five throughout the year with fresh produce from the garden? Based on your goals, you can determine how many beds you’ll need. Remember, if you’re a new gardener, less is more. Start small so that you enjoy the process without becoming overwhelmed. You can always add more beds next season.
If you’re planning to build multiple beds, sketch a design for the layout of your beds. You’ll want to create paths between the beds that are wide enough for a wheelbarrow. You can also add elements that tie beds together in the design, such as a trellis that arches over the path between two raised beds, allowing you to plant climbing vines like peas, beans, or cucumbers, onto a vertical support anchored in the raised beds. Not only does the trellis add beauty to the garden, it maximizes space for more crops.
Most vegetable crops prefer full sun, at least 6-8 hours. Some crops, like lettuce and Swiss chard, can tolerate less sun, but for good production of fruiting crops, sun is important.
A nearby water source is critical. Choose a site near the garden hose or rain barrel for ease of watering.
Consider the proximity of the garden to the kitchen. A garden closer to the home adds convenience when cooking meals. Additionally, a garden near your house often is better tended than one tucked into the far back corner of the property. It’s easier to harvest beans, snip fresh herbs, or pull an errant weed when the garden is nearby.
Select a level site for the raised bed. Trust me. We’ve built nine raised beds and installed them in our sloping garden. While a sloped garden can still support raised beds, it’s much more work to build the bed and prepare the site.
Once you’ve selected your site, remove the sod and any weeds. You can either dig out the top layer of grass, or you can lay a thick blanket of cardboard or newspaper on the grass, which will kill it and serve as a weed barrier. Cardboard is my preferred method.
Now, you’re ready to build your bed.
The list of materials and instructions below pertain to a 4-foot by 8-foot raised bed. While this is the most common size, you can alter the size of the bed to your preference. However, for ease of planting and harvest, a 4-foot width is ideal in order to reach the plants from either side, without stepping into the bed and compacting the soil.
• (3) 8-foot long wooden boards, 2-inch width, 8-inch height. (If you do not own a table saw, ask the hardware store to cut one of the boards in half for you, resulting in your (2) 4-foot long end boards for the bed.) Do not use treated lumber, as the chemicals can leach into the soil—and your crops.)
• (12) 3-1/2-inch deck screws
• 2-inch x 10-foot metal conduit tube, cut into 1-foot segments
• Woodworking clamp
• Tape measure
• Cordless drill and drill bits
1. Prepare a hard, flat work surface. If you have not already cut one of the 8-foot boards into (2) 4-foot sections, do that first.
2. Begin with the 4-foot long boards. From the right edge and top of the board, measure 1-inch and mark the board with a pencil. Measure 1-inch from right edge and 1-inch from the bottom of the board and mark. Finally, measure 1-inch from the right edge and 4 inches from the top, placing a mark. Mark the board on the left side as well. (Measuring 1-inch from the left, then 1-inch from the top, 1-inch from the bottom, and 4-inches from the top.) Repeat for the second 4-foot board. The marks indicate where to drill the screws to attach the 4-foot and 8-foot boards that create the frame for the raised bed. First, though, you’ll want to predrill the holes to avoid potential wood splitting.
3. Using a wood clamp (or a helper), align the short and long boards at the corners, with the longer board flush with the inner edge of the 4-foot board. Fasten the boards with the screws. Repeat on all sides, making certain the boards are straight.
4. Once you’ve built the frame, place it on the site to ensure that it is level. If it isn’t level, move the frame aside and remove any high points in the soil with your shovel. Place the frame back on the site.
5. To support the bed and ensure it doesn’t bow, place a metal pipe in each corner, as well as at 2-foot increments along the length of the bed, flush against the inside of the 8-foot board. Using the mallet, pound the pipe into the soil until the top of the pipe is flush with the top of the board. For additional stability, you can screw the wooden frame to the pipes, but it’s not necessary. The pipes serve a dual purpose: they add stability, but they can also serve as the base for PVC pipe, which, when gently bent, can create a low tunnel over your raised bed for season extension. By adding the arches of pipe, as well as clear plastic sheets, you’ve created an environment that is typically 10 degrees warmer than the outside air temperature, allowing you to grow crops longer into fall and winter.
Voilá! Your bed is ready. Now, of course, you need soil.
Filling the Bed.
Remember math class? To find the volume of your new raised bed, multiple length x width x height. If you’ve created a 4-foot wide, 8-foot long, 8-inch high bed, you’ll need 21.33 cubic feet of soil. 4’ (width) x 8’ (length) x .67’ (height).
You can fill the bed with a healthy, organic garden soil from a supplier, or you can save money by blending your own ingredients. A good formula includes 1/3 compost for micronutrients (I use both well-rotted horse manure and compost from our bins), 1/3 vermiculite to enhance moisture retention, and 1/3 peat moss, which adds lightness to heavy compost. Blend well with a shovel in a wheelbarrow and place in the bed. If you choose to forgo the vermiculite and peat moss, at least ensure that your compost to topsoil ratio is 1:1.
After you’ve filled the bed, water the soil well to allow it to settle.
If you plan to install a drip irrigation system or soaker hose, now is the best time so that you won’t damage your plants. Wind a 25-foot soaker hose up and down the bed, holding it in place with landscape fabric pins. Attach the soaker hose to a garden hose at a nearby faucet. You’ve just saved yourself some time in caring for your garden throughout the season.
Planting Your Garden.
Now, the fun begins.
Decide what you or your family like to eat, and create your garden plan. Many garden centers sell plant starts, but some plants—like beans, peas, and radishes—are simple to start from seed. Plus, there’s no better experience than harvesting food that you’ve grown and nurtured from a seed. To make sure your seed starting is successful, you’ll find tips here: https://www.permaculturenews.org/2015/06/24/how-to-grow-a-seedling-into-a-plant/
To increase the beauty and productivity of your garden, add flowers. A border of nasturtium or violas attracts beneficial insects, increasing pollination and eliminating many pests in the garden. Plus, many flowers are edible, making a beautiful addition to salads and other dishes. Flowers can be a pretty and practical addition in your vegetable garden.
With an hour or two of work, you’ve created a perfect bed to help you grow delicious, nutritious food. Enjoy your harvest!