My hubby put in 4"x4" posts, then assembled four 4"x10' PVC type tubes for each row, which he screwed together. We hung them on the posts using plumbing tape.
I drilled 2.5" holes every 6 inches using a drill.
Then I used weedbarrier on the end of the tubes, secured with hose clamps. We discussed using solid end caps, but I liked the idea of having drainage on the ends.
We love the "Square Foot Gardening" method and I've had great success with 'Mel's Mix' of vermiculite, three different composts, and peat moss in the greenhouse.
My hubby built a garden box in the garden, so the kids and I were able to mix the different dirts in the box. Using old milk jugs, we slowly filled each hole and tube up with dirt. We had to cut our workday short after our eldest got dirt in her eye. We took a trip to the ER after irrigating her eye at home with saline solution to make sure it was completely out (it was!).
(You can see that now we were wearing goggles to keep dirt out of our eyes!)
We were able to re-use the 6" drip system tubing we used on the strawberries last year and fed them into the tubes, luckily they were the perfect length, saving us from buying more tubing. I ran around hooking up hoses trying to make sure the water was flowing in each tube. We will need to add a pump eventually, since we water using reclaimed rain water, but to test it all out I hooked it up to the well water.
Then came the task up digging up the plants in the garden and transplanting into the holes.
We have about 320 holes.
I have about 200 or so plants STILL in the garden, so now I have to figure out what to do with them!
I found this plan and maybe we'll build this next: http://www.pvcplans.com/trellis.htm