GARDENING When tomatoes get the blues

Outdoor Living

The Blue OSU tomato, currently being trialled at the Organic Centre.
NEW VARIETY?The Blue OSU tomato, currently being trialled at the Organic Centre.

When tomatoes get the blues …

Hans Wieland

Apparently, there are around 7,500 varieties of tomato. This summer we’ve got 60 on trial. It may not be as much as German collector, Gerhard Bohl, who grows 3,000 varieties, but we’re fiercely proud of them. They are growing away, setting fruit and fighting aphids. They are side-shooted and comforted with Comfrey feed, and they get encouraging words each morning from dedicated staff and students.
All this effort is in preparation for their big day in August (date to be confirmed) when chefs Neven Maguire, Piero Melis and Bríd Torrades will be tasting, testing and asking: “Mirror, mirror on the wall, who is the sweetest of them all?” Hopefully, our tomatoes will be supported by lots of visitors in their bid to beat the sweet cherry tomato Sungold on taste.

We say tomato
But first and the reality that growing tomatoes in Ireland has only really been made possible for the wider public with the arrival of polytunnels around 30 years ago. So in comparison to the growers in southern Mexico, who cultivated tomatoes 500BC or the farmers of the Lower Andes, who have grown them since 1500, or the people of Italy, where the tomato arrived in 1522, we are really green behind the ears when it comes to tomatoes. Still, we shouldn’t leave it all to the People’s Republic of China, the number one producer in the world. It’s hard to compete with a nation that produces 34 million tonnes in one year!

Thinking colour
We can classify varieties of tomatoes according to size and shape from round to cherry, plum to beefsteak, but here I’ll focus on colour. Tomatoes were originally yellow to orange, before being bred mainly for red and then later for yellow again. The latest craze is blue.
The difference in colour is not just superficial. The nutritional profile changes when the colour changes. Yellow tomatoes have lots of niacin and folate, less vitamin C, and less lycopene than red tomatoes. Perhaps most importantly, they are lower in acid than red tomatoes. For people who love tomatoes, but suffer when they eat acidic foods, yellow tomatoes can be a good middle ground for salads, pizzas, sauces, and any other dishes where tomatoes may appear. I am especially looking forward to tasting our Yellow Zebra variety this year.
Red and pink tomatoes offer up what most of us think of as a classic or standard tomato flavour: acid and sweetness in balance. Two that are tipped to be among the winners at our contest are the Volkov and Sweet Aperitif varieties.

Out of the blue  
Us ‘tomato-heads’ are are excited about the blue tomato, a novelty that has sprung from a blue gene that was isolated at Oregon State University, which is legendary for its work with cold-tolerant tomatoes. This new tomato colour contains more of the antioxidants called anthocyanins than non-blue varieties. Anthocyanins are the healthy pigments found in blueberries, are the healthy pigments found in red wine and red, purple and blue fruit and veg. To produce the blue tomato, Professor Myers and his students crossed a domestic tomato plant with the genetic stock of a tomato that included a gene incorporated from a wild relative with anthocyanin-containing fruit to produce a healthier tomato.
At the Organic Centre, we are trialling the Blue OSU variety this year. Its colour ranges from a purplish blue to a dark, almost black colour. Interestingly, anthocyanin is only produced in the fruit in areas that are exposed to sunlight. If the fruit is shaded by a leaf, stem or calyx, that part of the fruit will remain green. Intense sunlight will lead to the most beautiful purple colour say breeders. However, here lies the problem: Our unique Irish Summer!
If you grow a variety that you like and that has a great taste, we would really like to know: Please get in touch!

Hans Wieland is training manager at The Organic Centre, Rossinver, Co Leitrim, which offers courses, training and information on organic growing and cooking, and runs an Eco Shop and an online gardening store. For more information, visit
Gardening questions or comments? Contact Hans at