Noblesville West Middle School Garden Club and HCSWCD Partner to Develop Accessible Raised Garden Beds

7/24/2019

Andrew Fritz, Urban Agriculture Conservationist

Accessible raised beds are important for persons with physical disabilities and for the elderly but also for anyone who has limitations in movement. But building a raised bed to accommodate all needs is difficult. For example, the raised garden bed must support a lot of weight especially when the soil is wet. It must be deep enough for roots to grow. It should allow for persons in wheelchairs to not only fit underneath the raised bed but be able to reach across it as well. And then, of course, it should last for more than a few years by delaying rotting while avoiding treated lumber for food safety purposes.

But this is a challenge that Emily Crapnell, Noblesville West Middle School science teacher and Garden Club sponsor, reached out to the HCSWCD urban agriculture program for assistance in 2018. The Garden Club, started in 2013, was in the process of a renovating their garden space which now required raised beds with some of them being accessible.

A traditional accessible raised garden bed (like this one) tend to rot or sag within a few years and do not allow for a person in a chair to reasonably reach all areas of the garden. Other raised bed options were cost prohibitive, like the Terraform Wheelchair Accessible Garden. Furthermore, the VegTrug, regretfully not discovered until this year, has a biodegradable permeable liner that allows water to come into contact with the wood. This means that the liner would need to be replaced meaning the soil would have to come out with it. This is cumbersome.

Design Thoughts

A conceptual model built using SketchUp to explore its potential usability

With no other viable options to meet our needs, we decided to design and build one ourselves. After some searching, we discovered accessible raised beds from the Sedona Winds Assisted Living Healing Garden, which became our primary source of inspiration. The design was contemporary, clean, and used sturdy construction that would appear to hold up over time. Conversations with Sedona Winds indicated that they were a success, too.

After conceptualizing by hand, the design was imported in SketchUp to help us visualize how users could interact with it.

The materials being used varied in size to achieve the look we were hoping for. We avoided using treated lumber and used only food-grade plastics (HDPE) to line the trough of the bed. The bottom of the trough would include a drainage pipe to decrease water-logging and, therefore, weight. Furthermore, the design would be fitted with irrigation.

Additional Model Images

Constructing First Raised Garden Bed

Together, we built the first bed to work out any kinks. Ideally, the project would require at least two people. And, if you had to build more than one, you could do so easily by cutting two (or more) of everything you needed.

Finished Product

The finished beds look and function as planned! Should you choose to construct something similar, consider the following recommendations:

Consider placing pavers or bricks on the bottom of the beds to keep the wood away from the mulch. This will keep the feet dry and less likely to rot prematurely.
Using HDPE as the liner is an excellent choice. However, it is difficult to seal with regular silicon caulking. There are special methods to be used since HDPE is fairly inert and usually is welded due to its high melting point (which is why it is regarded as food-safe). Click this link to learn more about ways to seal HDPE to prevent leaks. Keep in mind that the method of creating tight seams may, in and of itself, not be food-safe. Welding is likely the safest method.
Consider taking the extra (and timely) step of sealing the wood with a food-safe wood sealer. There are many sources online and advise you do your own research as it is difficult to independently verify the safety of these products. That being said, sealing the outside of the raised garden bed should be permissible since it is not coming into direct contact with the food or plants.