This story was originally published in September 2020.
Tomatoes are one of the most popular crops for home gardeners. After all, nothing quite compares to the taste of a fresh, home-grown tomato. With the growing season coming to a close, though, home gardeners may be getting anxious about the lack of juicy red tomatoes on their garden vines. Instead, their precious plants are peppered with stiff, green fruits that have yet to pop into their florid glory.
“It’s such a common thing that gardeners go through,” said Kate Garland, horticulture specialist at the University of Maine Cooperative Extension.
Before you panic about your pathetic tomato crop, check the variety. First and foremost, your tomatoes could be one of the heirloom varieties that is green when ripe, or long-season cultivars that still need time to mature.
“As gardeners, we want things to happen a little bit sooner than they normally do sometimes,” Garland said. “It’s basically a wait-and see-game. There are a lot of varieties that are a little bit slower than some other varieties. Some varieties are just worth that wait, too.”
If your tomato plant is in a shaded site, Garland said that sometimes that can slow things down in terms of ripening and overall development. This year, another likely culprit for unripened tomatoes is the unseasonably hot summer Mainers have experienced this growing season.
“The most likely answer is the high heat we had earlier [in the season],” said Caleb Goossen, organic crop and conservation specialist at the Maine Organic Farmers and Gardeners Association. “Tomatoes ripen best at temperatures averaging between 70 and 75 [degrees Fahrenheit], and when it’s hotter than that or colder than that, ripening can be delayed.”
According to the Cornell Cooperative Extension, when temperatures exceed 85 to 90 degrees Fahrenheit, the ripening process slows significantly or stops because lycopene and carotene, pigments responsible for giving the fruit their rosy hue, cannot be produced.
What’s a tomato-hungry gardener to do?
Over the course of the season, Garland said that regularly thinning your plants by removing dead material and pruning out suckers (the tiny shoots that form at the juncture between the stem and leaf) will help the plant allocate more energy towards fruit. At this point in the season, though, the best solution is to simply wait.
“With the return of cooler weather people may see a glut of tomatoes ripening — until ripening slows again because of colder average temperatures, that is,” Goossen said.
If you can’t wait for the weather to reach the Goldilocks temperature, take advantage of the fact that tomatoes continue to ripen off the vine. Goossen suggested picking the tomatoes, bringing them indoors and leaving them at room temperature to push them to ripen.
“This only works well with tomatoes that have started the ripening process, so look for fruit that is beginning to ‘blush,’” he said.
Goossen also said eager gardeners can put small quantities of under-ripe tomatoes in a paper bag that is loosely cinched or rolled at the top to trap ethylene, a plant hormone naturally produced by ripening fruit, which will spur them on to ripen.
“To really make it go, you can include an apple in the bag because apples put off a lot of ethylene gas,” Goossen said.
If you have a frost coming in and your tomatoes still aren’t quite ready, you will want to harvest those tomatoes and take advantage of the off-vine ripening properties. Garland said that come fall, she is ready at the drop of a hat to harvest her salvageable tomatoes if she knows there is a good chance of frost upcoming. She then sorts that final harvest into boxes by ripeness: one for red tomatoes, one for blushing tomatoes and another green-but-fully-sized fruits.
“That allows me to gradually get fresh tomatoes over time,” Garland said. “If you have the ripe ones in with the green ones, that encourages them to ripen, but I like to slowly eat fresh tomatoes throughout the fall. I’ve had them right up to Thanksgiving.”
Or, you can embrace the tomatoes as they are, in all their green glory. Unripe tomatoes may not be as sweet and nutritious as true green tomatoes, but the firm and acidic fruit is still delicious fried.
“There are green varieties of tomatoes, [but] the varieties that are traditionally red you can definitely harvest and eat them at the green stage,” Garland said. “It’s not a bad thing to have green tomatoes. You can do a lot of different recipes with them and make the most of what you have.”