Low Acid Tomato

May 10, 2024

For decades, gardeners from Spirit Lake, Milford, Cherokee, Storm Lake and Mallard have asked us which tomato varieties are “low acid”?  Some folks have sensitive digestive tracts, but they still wish to enjoy a fresh sliced tomato!  The answer to this question has changed!  In past years Del’s suggested ‘Jet Star’, ‘Lemon Boy’, ‘Cherry Sun Sugar’, ‘Yellow Pear’ and ‘San Marzano’ Roma tomato.  Some heirlooms were also thought to be “lower in acid” including ‘Mortgage Lifter’.  Many gardeners will tell us that they purchase certain cultivars of tomato plants because they are “less acidic”.  Today, when asked which tomato plants are lower in acid, my current answer is none of them!  It seems that all tomato fruits have about the same acidity.  There is not much difference in acidity between pink colored fruits, golden colored tomatoes, or orange fruited plants.  Most tomato fruits have about the same acidity.  To read more about this go to https://www.gardenmyths.com/low-acid-tomatoes/

Some horticulture researchers and food scientists will claim that the difference in acidity is low and that varieties with higher sugar content seem to taste less acidic.  The fruits seem to be less acidic due to their sugar content!  Proven Winners has been among the first to test their tomato varieties with a Brix score.  The Brix system is used to measure sugar content and is VERY important in the wine industry to measure sugar in a grape berry.  Proven Winners have been breeding tomato plants and ranking them by their Brix score and introducing those that have a higher score, sugar content.  I think this is noticeable in the varieties ‘Red Grape’ Cherry tomato, ‘Yellow Pear’ and ‘Gladiator’ Roma tomato with fruits that approach one pound each!

Both acidity and sugar content will also vary according to growing conditions.  Many things might affect acidity and sugar including the effects of drought and soil moisture.  Plant nutrition, soil pH, light, plant spacing, soil organic matter and the effects of insects and disease may also change acidity and sugar content.  A tomato variety believed to be low in acidity may not be low at all because your plant did not receive optimal growing conditions.  

One more thing to “digest” in this conversation is the protein Lycopene.  This “vitamin” or “supplement” is found in tomato fruits naturally.  The botanical name for tomato is Solanum lycopersicum which hints at their Lycopene content.  It is possible that many who think they have issues with tomato acidity might have a problem with Lycopene.  Colored tomato fruits like ‘Black Cherry’ and ‘Cherokee Purple’ have dark skin and or flesh.  Lycopene is higher in these two due to their darker color.  Del’s even offers the cultivar ‘Health Kick’ Roma tomato as it was specifically bred to have more Lycopene content.  It does sound as if there are important health benefits from Lycopene for most people, but even those benefits may be questionable.  Read more about Lycopene here.  https://www.medicinenet.com/lycopene/article.htm

Del’s Garden Center is offering all the tomato plants mentioned above for the 2024 growing season.  “So Todd, what tomato plant do you have that is less acidic”?  As senior horticulturalist at Del’s Garden Center, my answer is..…“IDK”.  I don’t know!  Clearly all tomato fruits are acidic and sugary.  Eat what makes you feel good.

– Todd Brockshus, Senior Horticulturist