After what seems like the longest winter on record, it’s finally time to start sowing tomatoes – my favourite of all homegrown crops. I love everything about them: the smell of the foliage, the little lobed leaves they kick out at the seedling stage and, of course, the amazing fruit which, if you follow a few tips and tricks, are better than any that money can buy. Perhaps surprisingly, many of these tips and tricks are the exact opposite of much received wisdom, so let’s go through them.
First and foremost, the single most important determining factor for tomato flavour is genetics. However, as someone who has scientifically trialled hundreds of varieties with the Royal Horticultural Society, the idea that heritage types are always the best is not one borne out by any good evidence.
Modern breeding work has led to the creation of some of the sweetest, most fragrant cultivars with rich, deep complex flavours – such as Sungold. By comparison, some of the more common heritage ones – such as Moneymaker – are watery and bland. I realise this is a fact that can often stir passions in the gardening world. I am frequently sent angry tweets whenever I point it out, but I promise you a fact it remains. The flavour intensity of a variety and its date of release are very poorly correlated when tested… which also came as a big surprise to me during the trials.
To save you the time of testing flavours for yourself, I can tell you that the following – a list that includes both modern and heritage – are among the best ever bred: Russian Rose, Costoluto Genovese, Marmande, Rosella, Sungold, Belriccio, Green Zebra and Green Grape.
Now let’s talk about water and fertiliser. I frequently see gardening advice that involves pouring on large doses of liquid feed every day. Let me be clear: this is the exact opposite of what every trial has ever shown. It also demonstrates a poor understanding of how plants work. Over-generous watering and feeding, in particular with nitrogen, causes the cells in the fruit to swell with water which ups their yield, but dilutes their flavour, quite literally. So avoid the temptation of going overboard. Likewise, growing the plants in garden soil, rather than compost, will give them a more even supply of water and nutrients, and almost certainly better flavour.
Finally, plants are living solar panels that use their leaves to create sugars, which are the building blocks for much of fruit flavour. While removing the odd leaf to allow sun to hit the ripening fruit is fine, stripping plants of every leaf hampers their ability to do anything – especially produce the best-flavoured fruit.
Moral of the story? Simply avoiding these complex, labour-intensive rules will give you much better harvests come the summer. So you will have more time to spend enjoying the fruits of your labour.
Follow James on Twitter @Botanygeek