*6 dog-eared picket fence pieces (@$2.35 per)
*One piece of eight foot redwood rough board (2x2x8 @$2.97)
*36 wood screws
*4.5 bags of garden soil (@$2.47/per. this expense can be eliminated through craigslist)
*50ft of polytubing
*36ft of emitter tubing
*free horse compost from craigslist
Four of those fence boards will be used for the sides (two per side). The rough board is used as the joining pieces in the corner (cut to 16" lenghts) and to anchor the finished bed in the ground. Always pre-drill the holes in the wood to avoid cracking the wood. Also, note how the corners come together in the photos, with the screws coming in at complimentary heights in the woods to minimize the stress on the wood. The horse compost seemed well aged, and i've heard of people planting stuff straight into it without a problem (potatoes). Bagged garden soil was mixed in with the compost to balance it out a bit. Poly tubing connects up with emitter tubing, 12 inch spacing between tubing (emitters are built in 12 inches apart)
They may be too short (only 11 inches tall) but you can always add another fence piece or two, so long as you cut your rough board longer. Seems like they would be perfect for shallow rooted crops. We'll see how well they hold up.
"la accion es la madre de la esperanza."