How to Ripen Green Tomatoes, According to Produce Experts

Ripening green tomatoes is a skill that lets you savor the full flavor of this versatile fruit. Recognizing when tomatoes are optimally ripe can be challenging, and consuming them too soon sacrifices taste. However, allowing tomatoes to ripen on the vine could invite unwanted nibblers. To help tomato aficionados maximize their harvest, expert gardeners and farmers offer insights on harvesting, ripening, and storing green tomatoes.

Harvesting Green Tomatoes

You'll recognize underripe tomatoes by their color. "Tomatoes that are green are usually not yet ripe," says Christopher 'Landy' Landercasper, director of organic agriculture for Sonoma's Best Hospitality Group. "All tomatoes are green before they turn red, purple, or yellow, or some other color or combination."

Indoor Ripening

Fortunately, it's possible to ripen green tomatoes after you've plucked them from the vine. Many people choose to after-ripen tomatoes indoors, says Daniel Cunningham, horticulturist and co-founder of Rooted In, a Texas-based nursery and garden center. "Not only does this practice prevent predation from wildlife and reduce exposure to extreme weather conditions, but it also might help give you more control and could even speed up the ripening process."

When to Harvest Them

If you live in a region with significant cold weather, Cunningham suggests harvesting all the tomato fruits on the plants before the end of fall so they can after-ripen safely indoors. Bear in mind:

• Green tomatoes left on the vines during a freeze generally succumb to the frost and are inedible.
• They should be harvested when the fruit begins to change color and soften to the feel, says Cunningham.
• At this point, most of the carbohydrates and sugars that will be sent to the fruit are already present in some form, but after-ripening indoors will enhance the flavor, he adds.

Don't Harvest Too-Small Green Tomatoes

When harvested while still immature, green tomatoes may rot before they have a chance to become ripe. "There is a fairly good way to tell which tomatoes have developed enough to further ripen," Landercasper says. He suggests this method:

• Take an average-sized tomato and cut it in half. 
• "If the gelatin holding the seeds is liquid enough that when you cut through the tomato, the seeds move, then tomatoes of that size and larger will ripen," he says. 
• However, a tomato will most likely rot before ripening if the knife cuts the seeds in half and the liquid around the seeds is not loose enough to allow the seeds to move away from the knife blade, Landercasper says.

Separate Ripened and Unripened Tomatoes

Depending on the type of tomato and when it was picked, some varieties might ripen in a few days, while others could take up to two weeks or more. "Check on your tomatoes frequently and remove those that have fully ripened," Cunningham says. "Also, if at any time through the after-ripening process you notice a mushy fruit or tomato with a bad spot, quickly remove and discard."

Ripening Green Tomatoes

Ripening is a natural process, so by placing your tomatoes in the proper environment, they'll continue to ripen without any hands-on work from you—but here are a few ways to get the best results.

Hang the Tomato Plant Indoors

Tomatoes that ripen on a vine taste better than ones that don't.

Transfer it: Instead of harvesting your tomatoes at the end of the season, dig up the entire plant (which will die anyway).

The right place: Hang it in a cool, dry spot that receives some light indoors (avoid overly sunny spots), and let the fruits color up on the vine.

Leave Tomatoes on the Counter

Experts agree refrigerating ripe tomatoes ruins their taste; it also halts the ripening process.

If you've brought slightly under-ripe tomatoes home from the farmers market or hauled some inside from your garden, leaving them on the counter will allow them to slowly ripen on their own. Store them at room temperature with the stem intact and the stem side facing down.

Paper Sack Method

Tomatoes rely on ethylene gas—not sunlight—to ripen, so keeping green tomatoes in a confined, temperature-controlled area once harvested will speed up the process. "Choose a confined spot, such as a paper sack or a cardboard box, that stays roughly around the 70 to 75 degrees Fahrenheit range," says Cunningham. "This will allow for better airflow and less humidity, so a better concentration of natural ethylene gas can hang around."

Add another fruit: Since other fruits release ethylene gas as they ripen, exposing a green tomato to another ripening fruit will help it mature faster. "If you need a tomato to ripen more quickly, put it in a paper bag with a ripe banana," Landercasper says. "The ripe banana will emit ethylene gas, and it will concentrate in the air in the bag, helping to speed the ripening of your tomato."

Banana alternative: If you don't have a banana on hand, an apple will also work, Cunningham says. Avocadoes and mangoes produce ethylene as well.