Build your trellis system when you plant the tomatoes. The tilled planting soil makes for easier digging, and the tomatoes need the support almost immediately.
Dig two 2-foot holes at the ends of each tomato row. Place these holes even with the tomato row or 2 o 4 inches behind it. If your tomato row is 8 feet long or longer, dig a third hole in the center of the row to give the trellis more support.
Place 8- to 10-foot-long stakes in the holes and secure them with soil. Wrap a length of wire around the top of the first stake and stretch it to the second and third stakes. Secure it at the last stake in the row to build a top tier for the trellis. Repeat the process with a second tier 1 foot off the ground.
Tie lengths of twine between the top and bottom wires at each tomato plant. These are their vertical climbing supports.
Tie the tomato vines to the twine as they grow up. Tie at sections of the main stem and use loose ties to avoid damage to the vine. Wrap the vines around the string to build more space, and train the vines along the top wire if necessary.