Frost is coming and the vines are still loaded with green tomatoes. The good news is that most of them will ripen indoors if you handle them right, and many will taste nearly as good as vine-ripened. The secret is ethylene, the natural ripening gas tomatoes produce. Once a tomato reaches a certain maturity, it no longer needs the plant; it just needs warmth and a little ethylene to finish the job. Your task is to harvest the right fruit at the right stage, then create the warm, slightly enclosed conditions that concentrate ethylene and coax the green ones to red.
Not every green tomato is destined to ripen, though, and one of the most common pieces of advice, lining tomatoes up on a sunny windowsill, actually works against you. Below you will find four reliable methods, a clear explanation of which green tomatoes are worth saving, and the truth about that windowsill myth. With a little sorting and the right setup, you can stretch your tomato season weeks past the first frost.
Key Takeaways
- Ripening is driven by ethylene gas and warmth, not sunlight. Ripen tomatoes in a warm spot, not on a sunny windowsill.
- Only mature green tomatoes will ripen well. Look for full size and a glossy, pale or whitish-green skin; small, hard, dull-green fruit will not ripen properly.
- The paper bag method with a ripe banana or apple concentrates ethylene and ripens a few tomatoes fast.
- For a big harvest, ripen tomatoes in a single layer in a box or pull whole vines and hang them indoors.
- Check often and remove any tomato that softens or shows rot, since one bad fruit can spoil the batch.
Which Green Tomatoes Will Actually Ripen
Sorting your harvest is the step that determines success. A tomato can only ripen off the vine if it has reached physiological maturity, the point at which it has stored enough sugars and is ready to begin the color change. Pick that fruit and it will redden indoors. Pick an immature one and it will only soften, shrivel, or rot.
Sort your green tomatoes by ripeness stage:
- Mature green (will ripen well): full-sized for the variety, with skin that has shifted from dull dark green to a glossy, pale or whitish green. Slice one open as a test and the seeds are surrounded by a jelly and slip aside rather than being cut through. These are your best candidates.
- Breaker stage (will ripen fast): any tomato showing a blush of pink, yellow, or pale color at the blossom end has already started ripening and will finish quickly indoors. Prioritize these for eating first.
- Immature green (will not ripen well): small, hard, dull dark-green fruit that has not sized up. These lack the stored sugars to ripen properly. Do not waste space on them; turn them into fried green tomatoes, relish, pickles, or green tomato chutney instead.
Harvest before the first hard frost, since frost-damaged tomatoes turn mushy and will not ripen. Wipe the fruit clean and dry, discard any with cracks, bruises, or soft spots, and only bring sound, unblemished tomatoes indoors to ripen.
Four Methods to Ripen Green Tomatoes Indoors
1. The paper bag and banana method
This is the fastest method for a small batch. Place a few mature green tomatoes in a paper bag along with a ripe banana or apple, both of which give off plenty of ethylene. Fold the top of the bag loosely closed to trap the gas while still allowing a little air exchange, and set it somewhere warm, around 65-70°F. The concentrated ethylene speeds ripening dramatically; check every day or two and you will often have ripe tomatoes within three to seven days. Use a paper bag, not plastic, because paper breathes and prevents the trapped moisture that causes rot.
2. The box or single-layer method
For a large harvest, spread the tomatoes in a single layer in a cardboard box or on a tray lined with newspaper, making sure none are touching so a single rotting fruit cannot infect its neighbors. Tuck a ripe apple or banana in among them to add ethylene, and loosely cover the box with newspaper or its flaps to hold some gas in. Keep it in a warm room around 60-70°F and check every few days, pulling out the tomatoes as they color up and removing any that go soft. This method ripens fruit more slowly and steadily, which is handy when you want a staggered supply rather than everything at once.
3. The whole-vine method
If frost is imminent and the plants are still full, pull entire plants up by the roots and hang them upside down in a sheltered, frost-free space like a garage, basement, or shed. The tomatoes continue to draw on the vine and ripen gradually over several weeks. Hanging keeps the fruit off surfaces where it could bruise and rot, and it lets you ripen a whole plant’s worth of tomatoes at once. Strip off any leaves to improve airflow and reduce mold.
4. Wrapping individually
To ripen slowly and store the longest, wrap each mature green tomato individually in a sheet of newspaper and arrange them in a single layer in a box. The paper traps a little of each fruit’s own ethylene while keeping them separated. Stored cool, around 55-60°F, wrapped tomatoes ripen over several weeks; bring a few into a warmer room whenever you want them to finish faster. This is the method for spreading a harvest out toward the holidays.
The Windowsill Myth
The most stubborn piece of tomato advice is to ripen green tomatoes on a sunny windowsill, and it is wrong. Tomatoes do not need light to ripen. The color change is driven by ethylene and warmth, not sunlight, which is why a tomato can ripen perfectly inside a closed paper bag or a dark box. Sunlight is not just unnecessary; on a windowsill it can actively hurt the fruit. Direct sun heats one side of the tomato unevenly, can cause the skin to toughen or the flesh to cook and soften in patches, and the fluctuating warmth often leads to uneven ripening and a shorter shelf life.
What tomatoes actually want is steady, gentle warmth in the 60-70°F range and a bit of ethylene. A countertop away from the window, a warm cupboard, or any of the enclosed methods above all beat the windowsill. So skip the sunny ledge and give your tomatoes warmth and trapped ethylene instead.
Speeding Up or Slowing Down Ripening
You can dial the pace up or down by adjusting warmth and ethylene. To ripen faster, raise the temperature toward 70°F, add more ethylene with a ripe banana or apple, and group tomatoes more closely in an enclosed bag so the gas concentrates. To slow things down and stretch the harvest, keep the tomatoes cooler, around 55°F, spread them out, wrap them individually, and skip the banana so ethylene stays diffuse.
One warning: do not refrigerate tomatoes you are trying to ripen, and ideally avoid refrigerating ripe ones too. Temperatures below about 50°F halt ripening and damage flavor and texture, leaving you with the mealy, flavorless fruit that gives store tomatoes a bad name. Keep ripening tomatoes at room temperature or cool-room temperature, never in the fridge.
Check your ripening tomatoes every couple of days regardless of method. Pull out the ones that have colored up to enjoy, and remove any showing soft spots or mold before the rot spreads. With sorting and the right warm, ethylene-rich setup, a frost-threatened crop can keep your kitchen in tomatoes for weeks. For more end-of-season harvest handling, see our guides to storing fresh herbs and freezing vegetables from the garden, or browse the full outdoor living hub.
Frequently Asked Questions
Do green tomatoes need sunlight to ripen?
No. This is the windowsill myth. Tomatoes ripen in response to ethylene gas and warmth, not light, which is why they redden perfectly inside a closed bag or dark box. A sunny windowsill can actually cause uneven ripening and a softer, shorter-lived fruit. Give tomatoes steady warmth around 60-70°F instead of direct sun.
Will any green tomato ripen indoors?
No, only mature ones. Look for tomatoes that are full-sized with glossy, pale or whitish-green skin, or that show a blush of color at the blossom end. Small, hard, dull dark-green fruit has not stored enough sugar and will not ripen well; use those for frying, pickling, or chutney instead.
How does the paper bag trick work?
A ripe banana or apple in the bag releases ethylene, the gas that triggers ripening, and the folded paper bag traps it around the tomatoes while still letting a little air through. Kept warm, the concentrated ethylene ripens the fruit in roughly three to seven days. Use paper, not plastic, so trapped moisture does not cause rot.
Can I ripen whole tomato plants pulled before frost?
Yes. Pull entire plants by the roots and hang them upside down in a frost-free garage, basement, or shed. The tomatoes keep drawing on the vine and ripen gradually over several weeks. Strip the leaves for better airflow, and remove any fruit that softens or molds so it does not affect the rest.
Should I put ripening tomatoes in the fridge?
No. Refrigeration below about 50°F stops ripening and damages flavor and texture, producing the mealy, bland fruit people complain about in store tomatoes. Ripen and keep tomatoes at room temperature or a cool room. Only refrigerate a fully ripe tomato briefly if you must, and let it return to room temperature before eating.