Sweet cherry tomatoes

Judith Adam

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Cherry tomatoes on vine
Cherry tomatoes on vine
Cherry tomatoes on vine

Why is it that every seed catalogue on my desk falls open to the tomato pages? Perhaps the seed companies have recognized my tomato obsession — bred in the bone, so to speak, from a tomato-growing family. My grandfather grew ‘Rutgers’ (developed in 1934 by Rutgers, New Jersey, Agriculture Experiment Station breeder Lyman Schermerhorn) in his garden for 50 years.

My current interest is fixed on sweet cherry tomatoes. The supermarkets stock brands of cherries in different sizes and colours (but without identifying cultivar names), and the seed catalogues are loaded with varieties for home gardens. Many are named for their sweet potential — ’Sweet Baby Girl’ (parkseed.com), ‘Sugary’ and ‘Sweet Chelsea’ (veseys.com), ‘Sakura Honey’ (johnnyseeds.com), ‘Red Candy’ and ‘Sweet Mojo’ (stokeseeds.com). Their sweetness has universal appeal, but how sweet are they? I’m a gardener, not a chemist. I looked around on the Internet and found some interesting information about sweet flavour in plant fruits.

Fruit sugars are expressed in Brix degrees, a scale for measuring the density of sugar in a water-based solution. The tool for this measurement is a Brix refractometer, or sugar tester—a six-inch (15-cm) pocket-size optical device. It works by squeezing a drop of juice onto a small glass window and looking through the device for a measurement. The Brix scale is essential in wine making, as it reveals the sugar content of grapes on the vine and when they are optimally suited for harvest. The scale runs from 0 to 40 per cent, and can be used to measure sugar in any solution (including cola drinks if you want to blow it off the chart!), or drops of juice squeezed from home-grown fruit or vegetables like berries, peaches and tomatoes. Some gardeners have written about their tomato-growing experiments, and while their information is not meant to be scientifically reliable, it’s certainly insightful about sweet flavour in cherry tomatoes.

The sweet flavour of tomatoes is influenced by the plant’s capability to manufacture both sugar and acid, by seasonal growing conditions (tomatoes produce less sugar in a cloudy summer) and by the gardener’s cultural practices (if you don’t water tomatoes through a drought, their sugar plummets). The acid is measured with the pH scale that is also used for indicating soil acidity and alkalinity. As an example, natural pineapple juice has a sugar rating of about 16.2 degrees Brix, and an acid rating of about pH 3.8. The relationship of the two measurements works like this: sugar flavour increases as the Brix measurement rises; the pH scale works backward to lower numbers, and acid flavour increases as the pH measurement lowers. The high sugar content in pineapple juice overwhelms the extreme acid in the fruit, and produces a sweet flavour.

Mystery-variety supermarket cherry tomatoes are generally around 4.8 Brix degrees, with acidity around pH 4.1, and you probably have an idea of what they taste like. Compare that with one gardener’s ‘Sweet Million’ cherry tomatoes, with a sugar content of 7.1 Brix and pH 4.1. Now that’s a sweet tomato!Sometimes seed catalogues will offer the Brix rating for tomatoes with high sugar capability. Stokes Seeds lists ‘Sweet Orange’ as having 9 to 10 degrees Brix, and ‘Cupid’ with 8.2 degrees Brix. If you want cherry tomatoes (or larger sizes of tomatoes) with a sweet taste, start plants from seed and select cultivars that are capable of producing high amounts of sugar. (Fortunately, ‘Sweet Million’ is sometimes found as started seedlings in garden centres.)

I’ve decided to have my own Brix refractometer ($59.99 at leevalleytools.ca). It’s a good tool for someone who loves growing tomatoes; and it’s also an idea for horticultural clubs to own one for their members’ use. Tomato-tasting competitions are great summer events for gardeners and I always enjoyed this at my Master Gardener group. If a Brix refractometer is available to give precise sugar ratings, this would really add a competitive edge. It’s all about growing the sweetest cherry tomatoes.

More about tomatoes


Useful plants: goat’s beard

To my mind, a useful plant is one that solves a problem — it will grow in challenging circumstances, requires little maintenance beyond irrigation (everything needs water) and is non-invasive (unless I want it to be). Goat’s beard (Aruncus dioicus, 5 feet x 40 inches/1.5 m x 1 m, Zone 4) is a large-scale perennial (looking something like a large astilbe) and a good gap filler in borders or massed under trees. The handsome foliage is fern-like in a husky way, and the creamy flower plumes arise in late spring on tall scapes, lasting for three to four weeks. When the flowers are finished, the seedheads can be cut back, and the foliage clump is an asset all summer. I grow it in dry shade, but this year will be putting some into areas of half-day sun, and I expect more and larger flower plumes in the brighter location. Look for the species plant, which is larger and showier than any of the named cultivars (such as ‘Kneiffii’, ‘Zweiweltenkind’ and ‘Southern White’).

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4 thoughts on “Sweet cherry tomatoes”

  1. Gail,

    Giving the tomatoes more sun should result in more fruit—a good idea! And the trench planting method is worthwhile.

    Cracking and splitting is caused by a sudden rush of water through the tomato stems and into the developing fruits. If the soil becomes too dry, when water is finally available the tomato plants will take up as much as they can get. That causes the interior tissues of tomato fruits to swell more rapidly than their skins can expand. You might notice a lot of cracking and splitting after a heavy rain, when the soil is suddenly flooded with moisture. The best way to prevent splitting is to be methodical about supplying a consistent amount of irrigation, without any dry days. A drip or soaker hose (laid under an organic mulch around the plants) might be a useful way to deliver regular irrigation without too much stress on the gardener. Another method is to hand water the plants deeply two or three times a week, ensuring there is always moist soil in the root zone. There are tomato varieties developed to resist cracking and splitting, like Park's Whopper CR Improved Hybrid (parkseed.com). These have a thicker skin, but might be worth trying as a comparison experiment.

    I could think about tomatoes all day!

  2. Thanks Judith: I've made a note and will try the Epsom Salts. I will also move the tomato patch to a new spot where they will get more sun.

    This past year I planted by laying the lower stems horizontally and keeping this area as a shallow trench for watering and this resulted in good growth, despite this west exposure with sun from about 11-12. My problems were split fruit, and just a general lack of taste. I topped up the bed with triple mix, City of Burlington compost (bless them), sheep manure together with Pres Choice Blood & Bonemeal. Maybe it was all too much!

  3. To Gail, January 27

    Hello Gail,

    Thanks for the tip about 'Sweet Million' seedlings at William Dam in spring. Yes, it's beautiful country out there.

    You didn't give a description of the problem(s) with your large size tomatoes, but I can make some suggestions. Grow them in sandy loam soil with good drainage (tomatoes don't like heavy clay soil). Tomatoes need a moderate air temperature without extremes of cold or heat —70F to 80F in daytime, and 50° to 65°F at night (lower than 32°F kills the plants, and above 88°F causes flowers to drop). Their soil should be consistently moist (feeling like sponge damp), which may mean irrigating daily in midsummer. A three-inch (8-cm) mulch of leaves or other organic material over the tomato roots helps conserve moisture. If the plants suffer moisture stress, you may encounter the ugly problem of blossom end rot, a sunken black patch on the bottom end of fruits where moisture has been withdrawn to keep leaves from wilting. Tomatoes benefit from feeding, but avoid fertilizers with high amounts of nitrogen (the first number in the nutrient analysis). For additional nutrition, add bonemeal to their soil for a calcium boost (more insurance against blossom end rot), and a cup of Epsom salts (magnesium and sulphur) scratched around each plant in June to increase the number of flower trusses. I hope you have a good crop this year!

  4. I've grown 'Sweet Million' and loved them. William Dam Seeds sells the plants at their farm in Dundas. (It's also a lovely drive out there.)

    I've had little success with larger tomatoes, however. Any tips for the frustrated grower?

    Love your magazine and newsletter: little bursts of summer…..


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