Should I remove tomato leaves in late summer to help fruits ripen?
Charles Dowding says: Indeed not! A gardener asked me, in early October, why her tomatoes were dull tasting and of mealy texture, then it emerged that she had followed advice seen on television to remove all leaves to encourage the fruit to ripen. The idea behind this seems to be that ‘sun on fruit helps it ripen’. But while sun on fruit can give extra colour, it cannot develop the full flavour, sweetness and texture one seeks in ripe fruits. Plants need leaves to photosynthesise, converting solar energy to sugars and other compounds required by fruit as they mature. (A study on the photosynthetic activities of vegetative and fruiting tissues of ripening tomatoes found that leaves account for 71 per cent of photosynthesis, stem tissue 14 per cent and green fruit 15 per cent.)
A good approach is to keep removing the lower leaves only, below the bottom truss of fruit, to improve ventilation and help keep blight at bay, but to keep all other leaves. You can encourage tomatoes to ripen by removing the plant’s main growing point in August, watering less in September and pinching out any new side-shoots; all this encourages it to put energy into swelling and ripening the existing fruit rather than into making new leaves and fruit.