If you’re reading this as May turns into June, and you live in the West, you know you’re going through a heat wave, including triple digit temperatures in parts of California. A more widespread - and longer - heat wave is expected in mid-June. And, long range forecasts are calling for a much hotter summer (July through September) than usual throughout most of North America.

This is not good news for your south and west facing backyard tomatoes, especially.

Give a listen to today’s newsletter podcast clip (a short one) from Episode 383 of last March, the 2025 Tomato Preview Show. Don Shor of Redwood Barn Nursery in Davis offers tips on protecting your young, west-facing tomatoes (as well as bell peppers) from developing sunscald or sunburn during an extended heatwave.

It’s a technique that allows commercial tomatoes to be picked early in their life, stored, possibly treated with ethylene gas, and then shipped to grocery stores after they’ve reddened up and gotten a bit soft…with parts of their stem still attached. These tomatoes receive a premium price, because they are labeled as “vine-ripened”.

Processors and grocery stores insist this fits the definition of “vine-ripened”. Actually, there is no legal definition of “vine-ripened”, according to the USDA. The closest they come is in their “standards” for a mature tomato, which might come as a shock to you who grow backyard tomatoes.

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From the USDA’s “United States Standards for Grades of Tomatoes on the Vine”:

§51.2172 Mature.''Mature'' means that the contents of two or more seed cavities have developed a jellylike consistency and the seeds are well developed. External color shows at least a definite break from green to tannish-yellow, pink or red color on not less than 10 percent of the surface.

You may have assumed that those grocery store “vine-ripened” tomatoes were picked red and shipped immediately. You may have noticed that the tomatoes had a “tomato aroma”. Actually, if they still have a piece of the vine attached to them, that is the part that is emitting the aroma, according to “America’s Test Kitchen”. They also quickly point out, however, that “…in blind side-by-side tastings, my colleagues and I have never been able to consistently find a difference in flavor” between on-the-vine and ethylene-ripened tomatoes.

They quote a study that reaffirms their findings. That study was published in “The Journal of Food Science - a Publication of the Institute of Food Technologists”. It was conducted primarily by the staff of Rutgers University Food Science and Plant Science Departments, with support from the New Jersey-NASA Specialized Center of Research and Training. Do any of these firms have ties to the commercial tomato industry? I’ll let a newspaper or magazine with a team of researchers try to track down that answer.

The title of the study was: “Quality Comparison of Hydroponic Tomatoes (Lycopersicon esculentum) Ripened On and Off Vine”.

Before moving on, a clarification for you real tomato heads from NeetPrep.com (which bills itself as “India’s #1 Classroom Test Series”) regarding the question of the correct biological name for the tomato:

“In 1753, Linnaeus placed the tomato in the genus Solanum (alongside the potato) as Solanum lycopersicum. In 1768, Philip Miller moved it to its own genus, naming it Lycopersicon esculentum. Genetic evidence has now shown that Linnaeus was correct to put the tomato in the genus Solanum, making Solanum lycopersicum the correct name. Both names, however, will probably be found in the literature for some time.”

OK, lets ask the first obvious, basic question about this tomato taste test: What is the difference between the taste of a hydroponically-grown indoor tomato and an in-ground outdoor grown tomato? Although I was entertained by the variety of answers I read at crowd-aggregation site Quora, primarily from hydroponic enthusiasts, permaculturists, and way too many people not clear on the concept, I will rely on Google’s AI summary of the difference, which may have problems of its own:

* Hydroponic Tomatoes:

* Controlled Environment: Hydroponic systems allow for precise control over nutrient levels, light, temperature, and humidity, which can lead to larger, juicier fruits but sometimes with a less complex flavor.

* Less Soil Interactions: Soil-grown tomatoes benefit from interactions with beneficial bacteria and fungi, which can contribute to unique flavors and compounds.

* Potential for Bland Taste: Hydroponically grown tomatoes may have a lower concentration of certain flavor compounds, leading to a more muted taste.

* Sweeter Taste: Some studies have shown that hydroponic tomatoes can be sweeter due to increased water and sugar content.

* Soil-Grown Tomatoes:

* Complex Flavors: Soil provides a diverse environment with organic matter, beneficial microbes, and minerals that can contribute to a more complex and nuanced flavor profile.

* Natural Conditions: Soil-grown tomatoes are exposed to natural variations in weather, sunlight, and nutrient availability, which can affect their flavor.

* Tangy or Earthy Notes: Soil-grown tomatoes may exhibit more tangy or earthy notes due to the complex interactions in the soil.

* Lower Sugar Content: Soil-grown tomatoes may have less sugar content than hydroponic tomatoes.

In summary: While hydroponic tomatoes can be convenient and productive, their flavor may not be as complex or intense as those grown in soil, though some varieties are being developed to address this.

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When I die and go to Purgatory to burn off my sins, I am sure I will be placed on a panel that does nothing but taste-test hydroponically grown tomatoes, trying to differentiate between bland and blander.

In other words, that’s not a study that backyard tomato growers could relate to. The look, aroma, taste and juiciness of a freshly picked, homegrown heirloom tomato will have you saying what my wife says every winter: “I WILL NEVER BUY A GROCERY STORE TOMATO THIS TIME OF YEAR!” Yes, after growing backyard tomatoes for every year of our 45 year marriage, I’ve created my own personal tomato Frankenstein. Hell, she won’t even touch grocery store tomatoes in the summer. Well, frankly, in this household, there’s no reason to buy a tomato in the summer. Just step into the back yard with your snippers, and have at it!

For those who have never grown tomatoes in the back yard (or front yard), your best chance for really tasting what a tomato is supposed to taste like is to head to a farmers’ market this mid-summer, and purchase a just-picked-that-day, mid-size heirloom tomato (not a one-ounce cherry tomato; not a 16-ounce supersized beefsteak-style tomato) and eat it as soon as possible. Your next stop after the farmers’ market just might be at a well-appointed nursery, to get an heirloom tomato plant that has been upsized from a four inch pot into a 2-gallon pot and is selling for $20. Or better yet, prepare your yard for planting a few tomatoes next Spring. You’ll find plenty of info on how to do that, including the tastiest tomato varieties, in the archives of the Beyond the Garden Basics newsletter as well as several podcast episodes at Garden Basics with Farmer Fred.

Oh, you want to check out past editions of the Beyond The Garden Basics newsletter? Although the current edition is free to all subscribers, only paid and Founding Members get access to past issues.

Be Your Own Tomato Junior Scientist!

Here is where we nicely dovetail the topics of upcoming heatwaves and tomato tasting: When an extended heatwave, especially the ones where temperatures that will exceed 100 degrees are forecast, do what Don Shor suggests in today’s newsletter podcast:

• Before the onset of heat, help protect your tomato crop from sunburn or sunscald damage by harvesting those exposed tomatoes that are at the breaker stage of development (just beginning to turn from green to yellow/pink) that are located on the west side of the plant (for those areas of the country where the heat builds up throughout the day) or the south side (if your heat tends to peak midday).

• Place the tomatoes in a shady spot on your kitchen counter. Don Shor says they will ripen to red in seven to ten days. Other sources say it may take a couple of weeks.

• Whenever they develop a nice shade of red and have a bit of “give” to them when you gently squeeze them, cut them open, examine and taste them. Note their look, aroma, flavor, and sweetness or acidity. Give each of those categories a score of 1 to 5 (5 being the highest grade).

•Perhaps at the end of that two week waiting period, there may be other tomatoes of the same variety growing in the yard that have reached full redness and feel ready to pick. You may have to wait longer than two weeks to do this portion of the taste test, hence the reason for writing the scores down.

• Pick them, examine them, taste them, and then grade those garden-ripened tomatoes.

• Was there any difference in the scores of look, aroma, flavor, and sweetness or acidity between a counter-ripened tomato and a garden ripened tomato? Let us know in the comments which tomato varieties you used in this experiment, and the scores!

Thank you for also listening to the Garden Basics with Farmer Fred podcast! It’s available wherever you get your podcasts. Please share it with your garden friends. And your subscription to this newsletter helps keep the Garden Basics podcast alive, as well. Thank you for your support.

Fred Hoffman is also a University of California Cooperative Extension Master Gardener in Sacramento County. And he likes to ride his bike(s)

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