We highly recommend creating raised garden beds. They provide easy creation of ideal soil and concentrate the nutrients in a deep, well-drained root zone. This excellent drainage helps prevent the spread of disease organism and helps you build healthy plants through healthy soil.
Here is a very good introductory article and video from the National Gardening Association. The full article is here: Making a Raised Bed Garden. The page also has some other video articles on vegetable gardening. Check it out!
Here is my take on the subject:
Raised bed vegetable gardens are great, regardless of your native soil. With raised bed gardens, instead of fighting poor soil conditions, you create an area above your soil line, where you gain control over the soil texture, pH and ingredients. Our Camarillo soil is alkaline, but porous, good and rich. It can become compacted, soggy and unhealthful (for plants anyway) during rainy periods, and even during normal watering.
What is a ‘Raised Bed Garden’?
A raised bed garden is any garden that is elevated above the soil; this does not mean one that built on stilts up off the ground. It may be filled with native soil, or if your soil is inadequate, soil-less mixes may be used. Our soil is young and full of minerals, and a good place to start.
The purpose of this exercise is to get the plant’s root zone above the soil where it has a chance to drain and breathe, even in times of heavy rain. Eliminating roots standing in water helps you control a large number of garden diseases. Any hard edging used around the beds is to maintain the contents of the beds.
Raised bed gardens can be contained with wood, stone, bricks, logs or other items to hold the bed shape, or they can simply be mounded up earth, as found in typical row-and-ditch type field crops. A cap over the soil made of compost, other organic soil amendment, covered with a layer of wood chips at least 2″ thick. The best moisture retention and wedd suppression comes once you get your mulch layer 4″ thick, but even 2″ of mulch reduces the water needed, reduces leaching of nutrients out of the root zone, and prevents the build up of salts, or ‘crusting’, at the soil. surface
Anything you plant – herbs, vegetables or flowers – will thrive in such a raised bed.
Raised Bed Garden Advantages
Raised bed gardens offer several advantages beyond a chance to create ‘customized’ soil, including:
Raised bed gardens warm more quickly in spring, allowing you to work the soil and plant earlier.
Raised bed gardens drain better and help prevent moisture-borne diseases.
Raised bed gardens are narrow enough to reach easily, so you don’t walk on or compact the soil. This loose soil aids the transmission of air and nutrients to the root system.
Raised beds mean less bending, squatting or stooping to tend your garden. This is an aid to both the young and old…
You can correct the soil pH in each raised bed to suit the needs of the plants you want to grow.
Even with the construction, upkeep of raised bed gardens is much easier than conventional garden beds.
How to Construct a Raised Bed Vegetable Garden
Raised beds with some sort of hard, raised edge are the most popular. The hard edging helps keep the beds and their mulch in place, bring the work up to you, and just look nicer.
There are lots of different materials you can use for raised beds, and we hope yours can be built from materials salvaged from the waste stream, giving you maximum ‘eco’ points. Wood is popular, marginally renewable, easy to work with and (somewhat) cheap. Concrete blocks, recycled sidewalk slabs, granite from a local quarry, or brick are more permanent options, but require more expense and labor to build. You can even use hay bales, arranged in some box-like configuration, and fill the space with amended soil and a top-dressing of mulch. Hay bales only last a year, but as the straw decomposes it adds to your compost pile for the next year.
Most raised beds are built with wood-edges, so let’s look at building a wood raised bed garden.
Step 1: Pick a spot for the garden. Most vegetables, herbs, and flowers ineed at least eight hours of sun per day. A flat, level area with easy access to water and room to get around. If you are a community garden grower, your spot is already picked out, so…
Step 2: Lay-out the size and shape of your garden. There are several possible arrangements shown on the ‘Antonio’ garden page.
During the lay-out, take time to double-check that you can access all parts of the garden without walking on the soil in the beds. Also, try to imagine your plants grown to their full size – will you still be able to reach all of it? In a correctly designed raised bed, soil doesn’t get walked on and it doesn’t get compacted. The best garden width is somewhere under four feet. With a 3 foot width, you can easily access the middle of the bed from either side. If you cannot walk around both sides of a bed, three feet is too wide. See what you are comfortable reaching to and let that be your guide.
Any lay-out you pick will work, just keep the width reasonable. Six inches is a good height for the edging, and many vegetables grow well in loosened soil that deep. If you have a choice, go deeper. Consider ‘double-digging’ the beds – dig out a shovel’s depth and set the soil aside, then loosen anothe shovel’s depth, add amendment, and replace the first layer of soil you removed, amending it in the process. The additional depth guarantees your plants’ root will have room to stretch out!.
Step 3: Prepare the Soil Below the Site. Once the beds are laid-out, you can get to work preparing the soil. Soil prep is determined by the depth of the bed you’re building, as well as the plants you’re going to grow there. For most vegetables and herbs, a 6″ to 12″ deep bed is OK, but you really want to loosen the soil with a shovel or garden fork to a depth of eight to twelve inches.
When you dig up the soil under the new garden bed, be sure that you do not create a ‘bathtub’ in the compacted soil; make sure that water is free to drain away. This is especially important if you have clay soils.
Step 4: Building the Bed.
Rot-resistant lumber such as cedar, redwood or one of the newer composite (plastic) ‘lumbers’ makes a long-lasting bed. Ideally, you will be able to ‘re-purpose’ lumber from the waste-stream for your beds. Two by six lumber is perfect, as it is easy to work with and will give you six inches of depth.
Cut your pieces to the desired size, then attach them together to make a simple frame. You can attach the sides in a number of ways. You can make a simple butt joints, and screw the corners together with galvanized screws. A short piece of 4″x4″ piece of wood in the corner and carriage bolts make strong corners. Metal angle (book-shelf) brackets also make a solid corner.
Step 5: Finalize the Location. Use a carpenter’s square to square up the box, and check with a level to make sure your frame is reasonably level in all directions. The filled beds won’t be moving very far, so anchoring them down is unimportant. If one side is too high, just remove some of the soil beneath it; once it is level, it will stay that way.
Step 6: Fill the Beds.
The whole point of a raised bed garden is to create perfect soil. Make your bed’s soil from a good of quality topsoil, compost, and rotted manure. Rake the beds level, you’re ready to plant or sow seeds.
Maintaining your New Raised Bed Vegetable Garden
Raised bed gardens require very little maintenance. Each season (or re-planting), top dress with fresh compost or dig the compost into the top several inches of soil. Tilling is not needed, and in fact, not desirable, as it destroys the soil’s structure. Keeping a 2″ layer of mulch on the soil helps retain moisture and keeps weeds from germinating.
Best of luck growing in your new raised bed vegetable gardens!
See our related article on Building Healthy Garden Soil.
read the next article: the French Kitchen Garden.