Updated: Nov 20, 2020
Pruning your home tomatoes can lead to more enjoyable harvests, if done correctly.
First, we need to know the reasons for tomato pruning:
Reason 1: Ease of harvest.
Reason 2: Appropriate airflow and light for healthier plants.
If you have spaced your tomato plants in a way that allows you to easily reach the fruit, you have already accomplished these and there's no need to prune your tomatoes; simply trellis them to support the weight of your bountiful harvests to come.
However, if you have created somewhat of a jungle by planting your tomatoes in large sections, it's beneficial to do some pruning in order to not fret future harvests.
These diagrams shows the major parts of a tomato plant. Today we're only focusing on finding and pruning the suckers.
The key is to reduce the number of suckers (a.k.a. leaders); reducing these will lead to less foliage. Suckers can be found at the node, or "armpit" of the plant- the point between a leaf and the main stem. (Don't confuse suckers with fruiting branches found on the main stem; these have obvious flowers or fruit on them.) When left un-pruned, suckers can become main stems.
Having too many main stems is what causes the "tomato-jungle" effect, leading to poor visibility of fruit and possible airflow issues. Prune suckers back at their base, always using a pair of sharp, clean pruners. (see photo)
In the pictures below, you can see a before and after of a young tomato plant that we are training to have just two main stems. Having just two main stems and constantly reducing suckers where necessary allows us to clearly see our fruit as well as have adequate airflow and sunlight for nearby plants.
Depending on how close your plants are together, you can choose to have one or multiple main stems.
Try to never cut more than 30% of the plant, so prune your plant gradually throughout the season.
Don't forget to trellis main stems to support the weight of your awesome harvests to come!