Tomato cages always seem to be too small, too flimsy and simply, not enough for the indeterminate tomato plants I grow. This year I decided to make a 3-D PVC grid to support my tomato plants. My final cost was about $55. The tomato portion of my garden is roughly 6'X7'. Since your garden will probably have different dimensions, your cuts will be different lengths than mine.
Step 1: What You Will Need
For my garden, I needed
---21-10' pieces of 1/2" PVC pipe
---8 -X shaped PVC connectors for 1/2" PVC
---38 -T shaped PVC connectors for 1/2" PVC
---a tape measure
---a marker, such as a sharpie
---an electric saw of some sort (I used a miter saw)
Step 2: Cutting Tips
Measure the PVC using the tape measure and mark it with the sharpie. PVC tends to break easily when cut with an electric saw. To prevent this, wrap the area to be cut with duct tape and re-draw the line on the the tape. The duct tape can be removed after the cuts are made. The length of the cuts for my garden will probably be different from your garden, but I will list them in the following steps so that they can be used for reference.
Step 3: The First Cuts
I started with the 4 corner pieces and 4 center support pieces and decided that 10 inches into the ground would be enough to keep the grid stable. I wanted each level of the grid to be 20" above the next, so I made my first 8 cuts at 30" each and pounded each 10 inches into the ground (I drew a line 10" in so that I could be sure to push each piece the same distance into the ground. The four corner pieces each should have a T-shaped connector bracket on top. The four center pieces should each have an X-shaped connector bracket on top.
Step 4: Hooking the T-brackets Together
On top of the T shaped brackets on top of each corner piece, your will need a length of PVC pipe roughly 1 1/2 " long. This short piece of PVC will be used to connect one T-shaped connector to the next. The short lengths of PVC will most likely not be visible in the final product. As is shown in the 4th and 5th picture of this step, 1 open end of a T connector should point towards the short end of the garden and the other should point towards the long end.
Step 5: Outside Bracing of First Level
I am going to refer to the 6' side as the short side and the 7' side as the long side. Each short side should be made of 3-18" lengths of PVC connected into one long piece using 2-T shaped connector brackets. Each long side should be made of 4-21" lengths of PVC connected into one long piece using 3-T shaped connector brackets.
Step 6: Long Center Grid Pieces
The long interior pieces should connect to the T-brackets on the short end of the garden. Each piece should be roughly 28" long. They will fit into the ends of the X-shaped brackets on top of the center support beams.
Step 7: Short Center Grid Pieces
You will need 3 short center grid pieces each 57"long. These go from 1 long side to the other long side, anchoring into the T-shaped brackets on the long sides. As these have no center support, they may droop a little, but can rest slightly on the long center grid pieces which DO have support.
Step 8: Rising to the Next Level
The corner pieces to the next level should each be 17" long. On top of each, connect another T-shaped bracket, 1 1/2" length of PVC, T-shaped bracket arrangement, like you did on the previous level.
Step 9: Center Pieces for Level 2
The 4 center support pieces should each be cut to 20" long and topped with X-shaped connectors, as in step 6. Arrange the center pieces the same way and with the same dimensions as you did for the first level (steps 5 and 6). On the top of each support post, add another 20" length of PVC. This time, though, top them with T-shaped brackets, instead of X-shaped ones.
Make the same cuts as for the previous 2 levels (steps 5 & 6) and assemble in the same manner. Step back and admire your handiwork. You are all done!