Indeterminate tomatoes continue to produce throughout the growing season rather than all at once. Because of this, they need good support that can hold the main stem of the plant, where the tomatoes will appear, as potentially heavy tomatoes increase in size as they grow and ripen. The best way to support indeterminate tomato plants is by using a metal frame cage or tower that has many horizontal bars to help hold the branches of the tomato plant for better air circulation, lower risk of disease and easier harvests.
Start with a tomato seedling you have already transplanted into the ground or one that you stated from seed. You'll want to wait until the plant is a foot tall before adding supports so you have full access to it for frost protection in the early weeks of spring.
Place a cage or tomato tower on the ground around the tomato seedling. Be careful as you push the cage or tower tongs into the ground so that you don't pierce the root system of the tomato.
Use plant ties in foot-long lengths to help hold the main stem of the plant to the cage if the plant starts to tip or not grow upright. Tie one end of the plant tie to the cage, loop it around the main stem of the tomato like a "U" shape, and tie the other end to the cage at the same point.
Add plant ties as often as needed to keep the stem straight, but typically you will only need to place ties 1 to 2 feet apart. If the point of the stem between ties starts to bow out, rather than grow straight, add another tie at this area as well.
Adjust limbs of the plant as needed to keep them running horizontally and carefully help them slip through the different rungs of the cage or tower to increase air circulation around the plant. Don't let the limbs and leaves bunch up around one another.
Protect your indeterminate tomato from hungry critters such as rabbits or woodchucks by using the plant ties to draw any branches upward that are on the bottom 18 inches of the plant. Having these juicy leaves out of reach should keep production of tomatoes going.