Gardeners seeking larger, more flavourful tomatoes should complete truss pruning before the end of June, according to greenhouse specialists at Juliana. The simple technique, which takes only seconds per plant, directs the plant's energy into fewer fruits, resulting in bigger and sweeter tomatoes.
What Is Truss Pruning?
Truss pruning involves removing some of the fruit on a truss—the cluster where tomatoes grow—to allow the remaining fruit to grow larger. The Juliana team explained: "To maximise the size of your tomatoes, consider truss pruning. This is especially important on larger, beefsteak tomatoes, where the weight of developing fruit can damage the plants."
The Royal Horticultural Society (RHS) notes that cordon or indeterminate tomatoes, which grow tall and need supports like wooden stakes, benefit from this practice.
When to Truss-Prune Tomatoes
Tomatoes cultivated indoors, whether in a kitchen or greenhouse, should be truss-pruned once they have developed seven fruit trusses. For those grown outdoors, gardeners should contemplate pruning when the plant reaches four trusses. Pruning in June, when plants usually begin setting fruit, ensures the plant understands which trusses to focus on well ahead of summer's peak ripening period.
In the UK, tomatoes begin to ripen from mid-summer onwards, though timing varies depending on variety, weather conditions and fruit size. In a greenhouse, tomatoes generally fruit from June through to October.
How to Prune Tomatoes
According to greenhouse experts, gardeners should aim to keep roughly four to six tomatoes per truss on indoor tomato plants. "Remove the smallest or misshapen fruits, allowing the plant to concentrate its energy on developing fewer, but larger, fruits," the Juliana team advised. "Regularly check your plants and prune as needed throughout June."
Think of it as guiding your tomato plant to direct its resources more efficiently: rather than sustaining eight or ten smaller fruits, it channels more sugar, water and nutrients into just four or five, yielding larger, more flavoursome tomatoes.
