Tomato Patch: Is It “Mealy, Mushy” Time?

Celebrity tomatoes (and a stink bug)
this morningm when the temperature was in the 40s

The thermometer got me to thinking this morning.  It was 43.7°F just before sunrise, the lowest temperature in the Tomato Patch since I set out the plants in May.

Most veggie gardeners know tomatoes are “warm weather” plants, not “cool weather” plants such as chard, turnips, broccoli, and cauliflower.  Many articles about tomatoes warn not to put them into your refrigerator because the 40°F temperature there will turn them “mealy” or “mushy.”

That was my concern this morning I read the outdoor temperature on our digital thermometer.  Will my “big reds” turn mealy at that temperature?  I vaguely remembered a Washington Post article I had read on the subject years ago, and after some searching on the Internet I found it.

The article is “Chilling Thoughts,” by Robert L. Wolke, professor emeritus of chemistry at the University of Pittsburgh when he wrote this article at the beginning of the tomato season in 2005.  Here’s the question he addressed:  “Why is it that people say it ruins a tomato to put it in the refrigerator?  How can this be?”

I’ll skip his comment about flavor chemicals, which he says do not decompose at cold temperatures.  He then addresses “texture,” which gets us to “mealy” or “mushy.”  Here’s the key part of Wolke’s answer:  “Tomatoes can suffer … ‘chilling injury’ if held at temperatures below about 50 degrees….  The nature and extent of the injury—which mostly involves changes in the tomato’s texture rather than its flavor—depends not only on the temperature and duration of chilling but also on the fruit’s ripeness.  That’s why no simple generalization can be made about the effect of refrigeration on tomatoes.”

The important factors: temperature + duration + ripeness.  Temperature factor is any temperature below 50°.  For duration, long-term chilling is worse than short-term.  On ripeness, Wolke explains that chilling tomatoes not fully ripe stops the ripening process and prevents development of full flavor and color.

How do I apply Wolke’s refrigerator principles to what’s happening in the Tomato Patch? Nighttime temperatures are starting to dip below 50°.  A few dips probably won’t do much damage to taste or texture, especially to fully ripe fruit, but as the weeks pass and low temperatures increase in length, damage potential increases, especially on tomatoes not fully ripe—the kind still growing in the Tomato Patch.

I plan to keep an eye on my tomatoes—the ones the stink bugs didn’t pinprick beyond edibility or the rains of Hurricane Irene and Tropical Storm Lee didn’t split—and at some point start picking and moving the best looking ones into the garage as protection both from late-season stink bugs and frigid nighttime temperatures.

I don’t plan to start moving them this week.  I’ll monitor local weather forecasts and the condition of remaining tomatoes.  If we have especially cold nights in late September or early October, perhaps I’ll some top-quality breaker-stage tomatoes into the garage.  If the nights stay relatively warm, perhaps I’ll move none.

Alas, fall is coming.  A killing frost will visit many of our gardens within the next month or so.  The end of Tomato Patch 2011 is a sad thought, but then in a few weeks seed catalogs will start arriving to jump start our fantasies about Tomato Patch 2012.

If you’re a genuine tomato freak and wish to read Wolke’s Post column, CLICK HERE.