
You only need to worry about pruning your tomato plant if it’s an indeterminate variety, meaning it continues to grow and produce fruit until it’s killed by frost. By improving ventilation, you're helping to protect the plant.

Humidity can make it easier for sicknesses to flourish, and it also causes the wounds that are created while pruning to dry up more slowly making the plant longer vulnerable. On the other hand, if your plant is in a humid environment (such as a greenhouse), remove everything below the first flower cluster to improve ventilation. They are important for helping to shade the ground until the plant matures.

Remove all suckers and their leaves below the first flower cluster.
