Green Tomatoes? Here's Why They Might Not Be Ripening, And How to Fix It
Tomatoes can be one of the most rewarding plants to grow in your garden, but they can also be a little frustrating. Not only do you have to keep an eye out for tomato plant diseases such as blight and blossom-end rot, but sometimes, you can care for tomatoes all summer, only for the fruits to stubbornly stay green and refuse to ripen. Luckily, there's a way to speed your plants along to harvest if they're producing green fruits that aren't turning red, yellow, or orange. At the end of the season, you can also pluck the last few green tomatoes off the vine before a frost and bring them inside to ripen.
Why Your Tomatoes Aren't Ripening
Usually, tomatoes that aren't ripening on the vine are overfed and overwatered. It happens to gardeners with the best intentions, but once the plant reaches the size you want, it's time to cut back on fertilizing. Typically, you'll only need to fertilize tomato plants two or three times during the season.
Reducing water, even to the point where a little stress (slight wilting) shows before you water again, can push the plant to ripen its fruit. Watering this way also will stop the plant from producing new fruits, which is good in regions with shorter growing seasons, because the late ones won't have time to ripen. If your season is long, you may want to water enough to keep more tomatoes developing on the plant, but just keep in mind that doing so will slow the others' ripening.
Finally, the weather can also play a role in ripening tomatoes. The best temperature range for ripening green tomatoes is between 68 and 77°F. Your tomatoes can still ripen outside that range, but the process will be slower. When temperatures reach over 85°F, the plants won't produce lycopene and carotene, which are the two pigments responsible for ripe tomato color. If your area has hot temperatures for an extended period of time, the ripening process might stop and you could end up with tomatoes that are yellowish-green or orange. There's not much you can do when the weather is too hot except wait for temperatures to go back down, when the ripening process will resume.
How to Ripen Green Tomatoes After Harvesting
You can't wait forever for temperatures to reach the perfect range; once the temperature consistently stays below 50°F, your tomatoes won't ripen any more on the vine. As long as the green tomatoes have started to turn color a bit (you should see just a touch of color at the blossom end of the fruit) and are a little soft to the touch, there's a chance they'll ripen indoors.
Related: How to Make Fried Green Tomatoes
Place your harvested tomatoes in an area that's 60 to 65°F (your pantry or basement might be perfect). Tomatoes don't necessarily need sun to ripen, so you can also try wrapping them in newspaper or a paper bag to help keep them cool and speed the process along. It can take a couple of weeks for them to ripen this way, so check on the fruits regularly. You can also try placing the tomatoes in a paper bag with an apple or a banana. Apples and bananas give off ethylene gas, which helps speed up the ripening process, and putting one of the fruits in a bag with your tomatoes will expose them to it.
Finally, you can try uprooting whole plants and hanging them upside down indoors. Sometimes, the tomatoes can ripen on the vine as the plant dies. Just be sure to get as much soil off the roots as possible before bringing the plant inside. And if you're growing tomatoes in containers, you can also move the whole plant indoors in its pot and set it in a sunny spot until the last fruits finish ripening.