Raised garden bed design downsized for construction ease
I have received quite a bit of feedback since the release of The Noble Research Institute Easy Access Raised Garden Bed. For the most part, the feedback has been positive. The one concern I hear most pertains to the weight of the truck tires. Some people are intimidated by the size and weight of the tires, and they question whether they will be able to physically handle the tires during bed construction. While this was not my experience constructing the bed, I can appreciate how some might have second thoughts.
In an effort to make bed construction more user-friendly, I recently constructed a similar type of bed using passenger car/light truck tires. These tires are approximately 8 inches narrower than the truck tires called for in the construction plans and only half the weight. The downside of using smaller tires is that you get a smaller bed. Our "mini" Easy Access Raised Bed is 2 feet shorter and 8 inches narrower than the full-size bed and about one-third less surface area depending on the size of tire used. What you gain in construction ease you lose in growing area. One benefit I overlooked when collecting tires for the mini bed was how easy it is to locate passenger tires. Tire stores catering to the public are seemingly located on every corner. This is not so with commercial truck tire stores.
The same construction techniques can be used to construct any downsized version of the Easy Access Raised Garden Bed. The only difference is the decreased number and size of the building materials.
During construction of our mini bed, I replaced the corrugated metal liner with a geotextile fabric liner manufactured by High Caliper Growing Systems in Oklahoma City. The custom-made "Smart Pot" liner eliminates the need for caulking and foam sealant to seal the ends of the bed. Additional benefits derived from using the fabric liner include moderation of soil temperature attributed to evaporative cooling and increased root mass due to fabric-induced root pruning. Growers who choose to install a fabric liner will need to equip the bed frame with some type of plastic or wire mesh support to prevent sagging when the bed is filled with growing mix. Smart Pot liners for any size of Easy Access Raised Garden Bed can be purchased from High Caliper Growing Systems (or 800-521-8089). A liner for a full-size Easy Access Raised Garden Bed (10-feet by 40-inches by 13-inches) costs $65, excluding shipping.
Gardeners looking for additional ways to reduce the cost of constructing an Easy Access Raised Garden Bed should consider the use of pallet lumber as a substitute for treated 2-inch by 4-inch lumber. Pallet lumber is typically one-third to one-half the cost of store bought and is available ready-to-use from pallet recycling businesses. The ends of our mini bed are framed with pallet lumber. While not as uniform in shape as store-bought lumber, pallet lumber is adequate for use in framing raised beds. An added bonus of using pallet lumber is the rustic appearance it contributes to the bed.
Both the standard size and mini version of the Easy Access Raised Garden Bed are available for viewing at the Noble Research Institute Center for Pecan and Specialty Agriculture, located on the main campus in Ardmore, Oklahoma.