Design

Wheelchair accessible table top garden bed design

There are a few styles of wheelchair accessible garden beds out there—check out the book Enabling Gardens for a more detailed discussion on this. These were the considerations we took into account when designing ours:

  • Cost. Our version costs about $70 per 4’ x 8’ foot table. However, we’d suggest using cedar boards for the sides rather than plywood, as these had to be replaced after just one season.
  • Strength. Build it so that you would comfortably stand several adults inside the bed.
  • Room underneath for legs. Some table top beds have straight sides, and gardeners in wheelchairs rotate sideways to garden. At Pearson, we need the tables that allow gardeners to access the beds straight-on. Having slanted planter sides is a good compromise—it allows a gardener to wheel underneath a few inches, but also maximizes soil depth.
  • Variable heights. We made a design that allowed for different heights, as there is a wide variety of wheelchairs configurations at Pearson. Our table tops range from 30” high to 39” high.
  • Enough depth and width for good gardens. You should aim for at least one foot of depth in the middle of the bed. 2 feet across is a good reach for a gardener in a wheelchair, and we made ours accessible on either side, so we doubled this to 4 feet across.
  • Materials. For the legs, we chose fir over spruce because it has more sap in it and is denser…therefore it lasts longer. And fir is cheaper in our region. Avoid pressure treated wood, which has chemicals. For the boxes, we used 3/4″ plywood and cut it to shape. Cedar is best but costs lots. We used outdoor deck screws and washers when screwing through plywood. We used a natural, locally made, one time application wood preservative, and then lined the inside with 6 mil vapour barrier. ONE CHANGE WE WOULD MAKE: To keep costs down, we used plywood. After one season, the plywood is starting to show signs of weathering. Solid wood would be a better choice, if you can afford it.
  • Clean design. Simple and easy to assemble, with clean lines.

Materials:

¾” plywood (standard sheet) You need 1.5 per bed
fir boards- 2” x 10” x 12 ft (2 per bed)
3” deck screws, no. 8 head
washers
wood preservative
6 mil vapour barrier
2”x 4” x 8ft (one per bed) to form the ‘spine’ of the bed at the bottom
1” x 2” x 8ft (2.5 per bed)
staples

design1 design2

  1. Start by cutting a ¾”plywood into equal thirds. Each piece is 16” wide, 8 feet long.
  2. Cut the 2” x 10”s with a length and angle such that when you cross the two legs, they add up to the height you are after, and allow for 4 feet of bed space at the top of the bed. This requires fiddling around to get the height and angle you need. I eyeballed it rather than using complicated geometry, but everyone has their own approach.
  3. Screw the two legs together, with four deck screws in each corner of the overlap.
  4. Make two more of these, exactly the same.

Here are 5 table leg sets, ready to go.

design3 design4

Now I attach the 16” high plywood strips to the sides of the bed. Use the washers and screws for this part, as there will be a lot of mass pushing down on these bed sides. If you assemble the beds upside down and use gravity to help you, it’s easy to get the plywood flush and level with the top of the legs.

Turn it right side up. It’s starting to look like something!

  1. Now you need to add the end of the boxes. To get an even end that you would attach the plywood end to, you add spacers. We used 2” x 4” pieces—4 per bed.
  2. Now cut the ends, out of plywood. Measure the distance across at the top of the bed (about 4 feet across, measure the depth of the planter (about 1 foot) and take the angle of the sides. These measurements let you pencil out the right shape for the end. Cut and screw it in. We also attached sides to the middle of the bed (on either side of the middle legs) so that the legs aren’t in contact with soil and it will last longer.
  3. The bottom. Measure the distance across. And the angle of the cut required for a flush fit with the sides. Cut and drop in. once you have a good fit, mark where the bed bottom hits the ends and sides of the bed, in preparation for the next step. Take out the bed bottom.
  4. Finally, make a ‘cleat’ around the entire bottom underside of the bed, and a spine running down the centre. This will support all of the weight of the soil. We used 1” x 2”s and screwed them in.
  5. Drop the bottom back in, and drill drainage holes in the bottom close to the centre spine (don’t drill at the edges, or the gardeners will get wet feet).
  6. Coat the entire thing in the least toxic preservative you can find (we found a good hippie local one) and line the inside with vapour barrier, stapling it in. Cut holes in the barrier to match the drainage holes.
  7. Fill with soil and get planting!

One last addendum: We added a top cap in the middle of the bed (a board the width of the bed), so that the ‘top ends’ of the legs boards are covered. When the ends are exposed to rain, the wood softens enough that the screws come out.

 

 

Comments are closed