Written by Chris Zdorovtsov (former SDSU Extension Community Vitality Field Specialist).
Consider the design of the space to make it accessible. Smooth paths will allow for strollers, wheelchairs and even wheelbarrows. If providing tools consider if you need some that are lightweight or types with extended handles. Consider if handrails or handles on garden beds or on structures will assist users.
Raised beds are not a necessity for all community garden sites, however there may be times when they should be considered. Many simply like the way raised beds look or feel they are easier to garden out of. So if aesthetics or ease of use are concerns, raised beds may hold the answer.
Raised beds should be considered when designing for a youth garden program, when the garden will be utilized by handicap or elderly participants, when the soil is potentially contaminated, when seeking higher yields in a limited space, and when desiring a longer growing season.
Raised beds have defined walkways and growing areas which is ideal when working with children. The walled beds will help little gardeners avoid accidental treading on plants. This may also be helpful if you find people are taking short cuts through your garden.
Raised beds will increase accessibility for people utilizing wheel chairs or for those that require sitting or standing. For most wheelchairs users the height should be 24-27 inches and the width should match the arm’s reach, approximately 2 ½ feet from one direction or 5 feet if accessible from both sides. For table-top gardens, where gardeners will be standing, it is recommended that they are 2.5-2.75 feet tall (or at average waist height) and 3-4 feet wide. Youth beds should be 24 inches or less and no more than 4 feet wide.
It may be hard to know if your soil is contaminated, so exploring site history is important. If you suspect there is a risk at the location you can build a raised bed. Bring in new soil media and garden on top of the space. With shallow rooted crops build your wall up a minimum of 6-8 inches. Additionally, if the site is simply poor quality (high clay soil, rocky ground, paved area) raised beds are a solution.
If limited on space a raised bed will produce more produce per square foot compared to a traditional home garden. According to production records over three years in a raised bed at Dawes Arboretum near Newark, Ohio raised beds produced an average of 1.24 pounds of vegetables /sq foot, more than double the conventional yield at .6 pounds/sq foot. Raised beds do not require the usual space between rows because no walking is done in the bed to cultivate or harvest. So vegetables are planted in beds at higher densities - ideally spaced just far enough apart to avoid crowding but close enough to shade weeds. Soil compaction can reduce crop yields up to 50 percent in traditional gardens. Raised beds have less of an issue since they are not being walked on.
Finally, soil temperatures are typically warmer in spring and fall so this will allow you to plant a little earlier and grow a little later. Plus hardware can be installed as part of the bed design utilizing cloth or plastic to build tunnel systems to protect the plants from cold weather. These systems can extend the growing season several weeks before and after frost.
Do consider that installing and maintaining raised beds will likely cost you more money than simply gardening in the ground. The installation process can be a more intimidating or require more effort than simply tilling. Keep in mind that they will drain faster and dry out more quickly, so they will likely need more frequent watering. These factors should also be weighed in the final decision.
For more information on community garden development please see the SDSU Extension Workbook: Diggin’ the Dirt, Community Style.