Will my tomatoes lose their flavour?
QDoes overwatering reduce tomato flavour? Robert Lewis, Manchester
AThe simple answer is yes – but it’s not that simple! Vegetables consist mostly of water. Tomatoes are about 94 per cent water, with a small amount of solid material that gives texture and flavour. The flavour of a tomato isn’t determined by a single gene, but by the relative amounts of sugars, acids and 17 volatile compounds (essentially the characteristic tomato aroma). Fruit high in both acids and sugars will have an excellent flavour, while tart fruit have a low sugar content and bland fruit have a low acidity. The volume of water in the fruit will have some influence on this, but so will temperature and nutrients. Reducing water leads to more solids and stronger flavour, but you need to find the right balance. Too little water will also lead to calcium deficiency in the fruit, causing blossom end rot. To maintain consistent watering I like to sink three, ‘bottomless’, 10 litre pots into holes in growing bags and plant my tomatoes into them so there’s a greater volume of potting compost for the roots. While they’re making leaf and stem growth, keep plants well- watered and reduce only once the fruit sets. How much is difficult to say. In sunny, hot conditions plants need more water – perhaps 1.5 litres (2.6 pints) per plant per day, but only half of this on a cooler, cloudy day. Other factors include avoiding temperatures over 25C (77F) and not exceeding the recommended rates when applying tomato fertiliser.
For best flavour, only pick tomatoes when fully ripe. Fruit harvested early or ripe fruit stored in refrigerators doesn’t produce the characteristic volatiles associated with fine tasting tomatoes.
It’s claimed that tomatoes from Israel are better tasting because the irrigation water is brackish. If you want to experiment, water a plant once at fruit set with 1.5 litres (2.6 pints) of a stock solution made up of 40g (1.4oz) of salt per each litre of water. I haven’t tried this myself, so it’s at your own risk!