How to Ripen Green Tomatoes
Fall is underway and there are still plenty of tomatoes in the garden, many still green. As temperatures drop consistently below 60 degrees, they are less likely to grow red on the vine and as soon as that first frost hits, it’s game over. New fruit is unlikely to develop once cool weather hits, but with a little help, those green tomatoes already on the vine can still beat that dreaded first freeze.
Covering plants with row covers or blankets at night can raise the temperature a few degrees to extend vine-ripening, but eventually it won’t be enough to combat cool weather. Eventually, the best chance for season end tomatoes will be to bring them indoors to finish the process. Potted tomato plants can simply be taken inside or entire plants may be uprooted and hung in the garage or basement to finish ripening if frost is in the forecast. If you’re seeing a bit of red on those green tomatoes, picking them individually and bringing them inside may be the best chance for ripening tomatoes at season’s end. Like many fruits, tomatoes continue to ripen once they’ve been picked.
Ethylene is a gas produced by fruits, including tomatoes, that promotes ripening. Many commercial tomatoes are actually picked while still green for shipping and ripened at their destination by introducing them to an ethylene-rich environment. Although it sounds a little nefarious, the practice is common. Tomatoes ripened after picking tend to be a little less flavorful than their vine-ripened counterparts, but for home growers, it’s a great way to rescue those late-season crops and can be done naturally and with little effort.
Tomatoes that have been given a head start on the vine have the best chance of ripening once picked. Give green tomatoes a little squeeze. If they give a little, the ripening process is already underway. Better still, tomatoes already showing signs of reddening are good candidates for post-pick ripening. Skip fruit that is marred or showing signs of decay. No amount of indoor ripening will improve them.
Left on the countertop, tomatoes will produce ethylene on their own and ripen eventually. Depending on the variety and how ripe they were when picked, the process can take several weeks. With a little help, though, ripe, red tomatoes are right around the corner.
Tomatoes aren’t the only fruit cranking out ethylene. Storing green tomatoes with other ethylene producers can speed up the ripening process considerably. Apples are a good choice, but bananas are ethylene producing powerhouses.
Select a banana that is yellow, but still shows some green at the ends. Barely green bananas are in their ethylene producing prime and the gas they release can reduce the time it takes to ripen picked tomatoes by days or even weeks.
Wash tomatoes and allow to dry completely before storing. For just a few tomatoes, place them in a paper bag with a banana and store at room temperature out of direct sunlight. Avoid high humidity, which can lead to decay or fruit fly issues. Larger quantities can be placed in a cardboard box instead of a bag. Leave a little space between tomatoes to improve circulation and speed up the ripening process. If dealing with an especially large harvest of green tomatoes, wrap each tomato in paper or place a few sheets of newspaper between layers to limit contact.
Check on tomatoes daily and remove any showing signs of mold or disease. Once ripened, tomatoes should be used within a week for best flavor.