Ask any square foot gardener what they enjoy most about using the method, and they'll most likely tell you that the vertical part is their absolute favorite. I sure know it is to me, and it can really give you alot more yield from the available space. Just make sure to build the trellises relatively strong, because in the end you'll regret not doing so. A new trellis system was added in my garden recently, and I wanted to share the building process with you.
Two individual trellises would be constructed in the swc area for the tomato plants of next year, and 12" deep holes were dug for the 4x4 posts that would support the 2x4 framework.
The first thing to do is to set the outermost posts, because they become the reference for the two in the center. Since all things constructed are done so without help, I've learned to be creative with the tools available to me. By clamping a level onto two adjacent sides of the post, it can easily be made plumb by only one person.
Next, a scrap piece of 2x6 is used as a kicker to keep the post plumb without me holding it. A couple of deck screws are started for connecting it to the post, and care must be taken to make sure the bottom portion of the board is against the ground, and also that the post is relatively plumb both ways before attaching it.
Once things are pretty good, just drive one screw in all the way, which will make for a pivot point so that the post can be moved slightly forward and back when finalizing plumbness in the next steps.
In the next photo, you can see that another kicker has been attached to another side of the post, and this is needed to keep the post from moving left or right when pouring the concrete later. Since the post needs to be tilted forward to become plumb, the kicker is driven slightly forward by pounding it at the location where the 8 lb. sledgehammer rests on it.
Photo below - the bubble of each level is positioned side by side so that checking for plumbness in both directions is done very easily.
Once plumb, it's time for pouring concrete into the post hole. I always use a 5 gallon bucket and shovel for mixing it, and the smaller one has some nasty water that was collected from other containers on the property that held water from a previous rainfall. Yeah, it looks gross, but isn't a problem for the application. The piece of rod laying on top of the bucket on the left is for prodding the poured concrete with - which essentially causes the mixture to flow into all crevices surrounding the post.
The post at the far end is done the same way, and final positioning is done before the concrete begins to setup. Depending on the time of year the work is performed, the concrete should be allowed to cure for 1-2 days before attaching anything to the posts.
A piece of twine is then stretched between the posts - allowing the same sides to be the reference for all other future posts installed.
Photo below - the next post is set into place using the twine as reference. A slight kink in the string indicates that the post needs to be moved to the left by a fraction, and to do this - the bottom part of the post is tapped with the hammer just a bit, then checked for plumb and by the twine once more. Once adequately plumb, the post is held into place by kickers as done previously, and concrete poured into the hole.
Photo below - once concrete has setup with 2 posts that'll be used for a particular trellis, the installation of 2x4 joist hangers is begun. I find that they make for a much neater connection between the posts and boards, and cost less than a dollar each, too. The cross beam for the bottom is always done first, and this one will need to be just above the top of the swc.
A 2x4 is then cut 1/2" shorter than the distance between the insides of both posts. One end is placed into the joist hanger already attached to its respective post, then a four foot level laid on top for indicating the position for the second hanger to be installed.
Proceed to part 2.......