this season we have been very intentional about pruning our tomato plants. we have never gardened in such a small space so pruning is essential. this way our tomato plants are growing up rather than out & taking up more space than needed.
in order to encourage growth upward instead of outward, cut the side branches from the stem up to 3-6 inches from the soil line.
another way to prune your plant is by removing the "suckers" located in the joint connecting the side branch from the stem. if the suckers are allowed to grow, this will lead to a more dense, bushier tomato plant.