How to ripen green tomatoes before frost or late blight damages them

green tomatoes
Photo by Connie Oswald Stofko

by Connie Oswald Stofko

I received this question from a reader, and it’s probably something that will help other gardeners, too.

My tomatoes have just started to ripen. If I pick them totally green, before they get late blight, will they ripen in a bushel basket?

Paula

You can pick green tomatoes and get them to ripen with flavor and color similar to what you would have gotten if they were ripened in the field, according to this article from Cornell University. The key is picking them when they are showing the first signs of ripening (no earlier) and keeping them at room temperature.

“Mature green” tomatoes are almost full grown, but do not yet show pink color, according to A Harvest of Green Tomatoes, a pdf from the Cooperative Extension Service of the University of Alaska Fairbanks. Cream-colored streaks are noticeable at the blossom end. The skin is not easily broken or rubbed loose when scraped with the thumbnail, and the fruit yields to slight hand pressure.

Tomatoes are considered mature enough if the pulp that surrounds the seeds has become jellylike and the seeds slip aside and cannot be cut by a sharp knife when the fruit is sliced.

Tomatoes that have not developed the jellylike condition and have soft, white seeds that are easily cut are too immature for harvesting with the hope of ripening. Immature tomatoes, if they ripen, ripen much more slowly than mature green tomatoes and usually shrivel in the ripening process. This results in poorly colored fruits that have a tough texture and an inferior quality.

If you need to pick immature green tomatoes, don’t despair. The pdf A Harvest of Green Tomatoes has recipes for cooking with green tomatoes.

Get detailed instructions on how to ripen green tomatoes in this article from eXtension, a group of cooperative extension services that includes Cornell Cooperative Extension.

Here are the basic steps for ripening green tomatoes:

  • Pick only tomatoes that are free of disease or damage.
  • Store tomatoes in boxes, one to two layers deep, or in plastic bags with a few holes for air circulation. If you have a moderately humid room, simply place them on a shelf.
  • Keep fruit out of direct sunlight. They may be stored in the dark.
  • Tomatoes should be stored at room temperature, 70 to 75 degrees Fahrenheit, according to this Cornell University article, or 65 to 70 degrees Fahrenheit, according to the article from eXtension. Do not refrigerate the green tomatoes because “this will absolutely destroy their flavor,” according to the Cornell article.

Tip: Storage at room temperature applies to ripe tomatoes, too. Tomatoes are a warm-weather fruit and lose their flavor when they are refrigerated. This is why the tomatoes from the supermarket don’t taste good after their long ride in refrigerated trucks, according to this Tomato Growing Guide from Cornell Cooperative Extension in Clinton and Essex Counties.

Tip for ripening tomatoes on the plant: If you have any flowers on your tomato plant after the first week of August, cut off the flowers to ensure that the plant puts all its energy into growing and ripening already existing fruits, according to the Tomato Growing Guide.

4 Comments on “How to ripen green tomatoes before frost or late blight damages them

  1. Thanks for this information…I have experimented with this, after asking the question, and now have 5 half-bushels of tomatoes at different stages of ripening on my dining room floor. The first of which will be ready to can tomorrow. I covered them with a towel and they seem to ripen nicely.
    Paula

  2. I have had to pick green tomatoes every year in September or October. My kitchen table is covered with bowls of them. Last year we ate our last red tomato from our garden in December! Way better than letting that cold rot set in if you leave them too long on the vine.

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