Trellising and Training Tomatoes (cont)
By: Shepherd Ogden
Training Indeterminate Tomatoes
Once your trellis is set up and the young plants are attached, the training begins. Training is important because it allows you to control how the plant grows, how many fruits it sets, and when.
Look closely at how a tomato vine grows. You'll see that it starts out as a single stem with leafy branches and flowering branches. But soon sprouts (sometimes called suckers) appear and grow at the stem joint (called axil) of each leafy branch. Each of these will in turn produce both leafy and flowering branches.
After each of these axial stems reaches three branches, and just before the first flowers appear on the axial stems, pinch off its growing tip to stop further development. That way, except for the axial leaves, which you want, you can keep the plant growing as a single stem. This makes it easier to trellis, and equally important, it keeps the number of fruits low in relation to the foliage, which makes for better tasting fruit. Pinch plants this way about once a week or so.
Always keep in mind that fruit flavor is related to the amount of foliage on the plants, so if you prune heavily, it makes sense to remove some of the fruits as well.
In the North (zone 5 and colder), prune consistently and carefully. But don't remove more than a third of a plant's foliage at any one time, because that may shock the plant and hamper its development.
In the South (zone 6 and warmer), don't prune plants as severely, or they'll faint in the heat and the fruits will be more susceptible to scalding by the sun.
Once you understand this basic concept, the actual training of the vine is simple. Take the slack vertical string which is loosely attached to the base of the plant, and wrap or braid it around the growing vine. Do this a minimum of once per fruit cluster. As the plants grow taller, the slack in the string disappears, and you can periodically release and re-tie the knot at the top of the trellis to make more twine available.
Once plants reach the top of the trellis, pinch out the growing point of the plant. That will cause it to stop growing and start ripening the fruit already set. And if you want early fruits, simply pinch out the end sooner. This will cause the plant to ripen fruits sooner, though overall yield will be reduced.