Green tomatoes are unripe tomatoes that are usually light green, green-yellow, or green-red in color. While ripe red tomatoes are soft, juicy and full of flavor, unripe green tomatoes are firmer with a tart, grassy taste.
Many home gardeners end up with green tomatoes on the vine at the end of the tomato growing season when cool weather settles in. Green tomatoes will not continue to ripen once picked from the vine which leads to the question – how do you ripen green tomatoes to turn them red and flavorful?
Luckily, there are several effective methods for ripening green tomatoes indoors. With a little patience and TLC, you can transform green tomatoes into ripe, red beauties perfect for eating fresh, cooking, canning or making sauce.
Here is a complete guide on how to ripen green tomatoes successfully using various techniques.
Why Tomato Fruits Stay Green
Before learning how to ripen green tomatoes, it helps to understand why some tomato fruits fail to fully ripen on the vine in the first place.
Cool Weather
Cooler temperatures inhibit the ripening process. Once nighttime temperatures dip below 55°F, tomato fruits will no longer produce more of the pigment lycopene which gives ripe tomatoes their red color.
Without sufficient warmth, unripe green tomatoes will remain stalled in an unripened state.
Low Light Levels
Like temperature, light also influences ripening. As daylight hours shorten in the fall, the diminishming sunlight can prevent proper pigment development in green tomatoes.
Early Picking
Many gardeners harvest green tomatoes before the first frost to save the crop. But picked green tomatoes will not continue ripening without the sustenance they get from the vine.
Variety
Some tomato varieties simply ripen earlier or later in the season than others. Late-season green tomatoes are commonly seen in long season and heirloom types that take 85 days or more to fully ripen.
Cultural Issues
Factors like overwatering, underwatering, overfertilzing with nitrogen, diseases, pests and poor pollination can potentially disrupt the ripening process and lead to green tomatoes on the vine.
How Long Does it Take to Ripen Green Tomatoes?
The time required to ripen green tomatoes indoors depends on the degree of ripening the fruits have already undergone and the method used.
Smaller green tomatoes will ripen faster than larger, more mature green tomatoes. Pale light green tomatoes that are beginning to show some color change will ripen quicker than those that are fully green.
Here are some general guidelines for ripening times:
- Pale green tomatoes just starting to show some color – 1 to 2 weeks
- Green-yellow and green-red tomatoes – 2 to 3 weeks
- Firm, fully green tomatoes with no color break – 3 to 6 weeks
Using accelerated ripening techniques like exposure to ethylene gas will hasten the process. Leaving green tomatoes to ripen naturally at room temperature takes the longest amount of time.
No matter which method you choose, inspect the tomatoes every few days for signs of ripening. Once ripening starts, it proceeds quickly and tomatoes can go from green to red in just 2-3 days.
How to Tell When Green Tomatoes Are Ripe
As green tomatoes ripen, watch for these signs of readiness for picking:
- Color changing from green to yellow, then orange, then red
- Tomato skin softening and becoming less glossy
- Fragrant tomato aroma
- Yielding, tender flesh when gently squeezed
- Seeds turning from white to brown
- Shoulder or blossom end of tomato softening first
The ripening process begins from the inside out. So the inner flesh near the core will ripen before the outer walls and skin.
At first, you will notice suble color changes starting at the blossom end. As more chlorophyll breaks down and carotenoids build up, the green will give way to yellow, then orange, and finally red.
Gently squeeze the tomato periodically to check for softness. When ripe, the skin will lose its glossiness and the flesh will yield to pressure. Sniff for the fragrance of a ripe tomato as another indicator of readiness.
The jelly-like sacs holding the seeds will turn from white to brown as the fruit ripens.
Once fully red, move the ripe tomatoes to the refrigerator where they will keep for a week or so.
How to Ripen Green Tomatoes Indoors
Ripening green tomatoes requires providing warmth, ventilation, humidity and time for the natural ripening agents within the tomato to work their magic. Here are some of the most effective methods for finishing the ripening process:
Ripening on the Windowsill
The traditional way to ripen green tomatoes is to spread them out on a windowsill and allowing them to ripen naturally at room temperature over several weeks.
For best results, choose a south or west facing window that receives at least 5-6 hours of direct sunlight daily.
Place tomatoes in a single layer so they are not touching each other. Rotate tomatoes every few days so all sides are exposed to light.
Check tomatoes every 2-3 days for softness and color change. Once ripening starts, move the tomatoes to a shaded area so the direct sun does not overheat them.
Ripening in a Paper Bag
Ripening tomatoes in a paper bag speeds up the process slightly compared to windowsill ripening.
Place green tomatoes in a single layer in a plain brown paper grocery bag. Fold the top of the bag over to close it. Store bag on the counter out of direct sunlight.
Thebag traps the ethylene gases released as the tomatoes ripen which accelerates the ripeningeffect.
Check the tomatoes every few days for doneness and remove any fully ripe tomatoes promptly to avoid overripening.
Replace the paper bag once it gets dirty for best results.
Ripening with Bananas
Adding a banana or two to the bag with green tomatoes takes advantage of the ethylene given off by ripeningbananas.
To use this method, place green tomatoes and bananas together in a paper bag.
As the bananas ripen over 2-3 days, they will increase levels of ethylene in the bag and speed up tomato ripening by a week or so.
Burying in Straw
Burying green tomatoes in straw moderates their temperature and maintains high humidity creating ideal conditions for ripening.
Find a box or bucket large enough to hold your green tomatoes in a single layer. Place 2-3 inches of straw in the bottom of the container. Add a layer of green tomatoes. Cover with another 2-3 inches of straw.
Store the container in a cool, dark place checking frequently. Redistribute straw if any tomatoes are not fully covered.
The insulation from the straw protects the tomatoes from cold while providing ventilation so they don’t rot. The straw also retains moisture to keep humidity high.
Wrapping in Newspaper
For a quick and easy method, individually wrap each green tomato in newspaper securing with tape, string or rubber bands.
Keep wrapped tomatoes in a dark, 70-75°F location checking every few days until softened and colored. The newspaper insulates while allowing oxygen circulation.
Ripening on the Vine
If frost threatens before tomatoes fully ripen, you can pull up entire plants, roots and all. Replant in containers and move to a protected area like a porch or greenhouse to continue ripening on the vine indoors.
Prune off any diseased or insect-infested foliage. Water plants as needed until remaining tomatoes fully ripen over a period of weeks.
Storing at Room Temperature
Simply leaving green tomatoes at room temperature on the counter will allow them to gradually ripen over several weeks. Avoid placing tomatoes in sunny windows where heat can build up and cause spoilage.
Sort through tomatoes every few days and remove any that are ripening or starting to get mushy. Keep counter top temperatures in the 65-75°F range for best results.
How to Speed Up Ripening of Green Tomatoes
While green tomatoes will eventually ripen on their own, there are some tricks to accelerate the process:
Ethylene Exposure
Exposing green tomatoes to ethylene gas will hasten ripening. In addition to placing tomatoes in a bag with a banana, you can also try these options:
- Apples – Add an apple to the bag with green tomatoes. Apples produce ethylene as they ripen.
- Ethylene tablets – Use specially made ethylene tablets or sachets formulated to ripen fruits. Follow package directions.
- Carburetor cleaner – Spray or fumes from carburetor cleaner contain ethylene. Do not spray tomatoes directly.
Maintain Warmth
Keep tomatoes at a temperature between 65-75°F. Warmer air will speed ripening but too much heat can cause uneven or poor color development.
High Humidity
Misting tomatoes or using a humidifier in the ripening area will provide a humid environment to encourage faster ripening.
Light Exposure
Some sunlight or artificial light will help move chlorophyll breakdown and color change along more quickly compared to total darkness.
Elevated Carbon Dioxide
One study showed ripe tomatoes release CO2 which helped accelerate ripening. Placing tomatoes in a sealed environment may raise CO2 levels and hasten ripening.
Ethrel®
Applying Ethrel or Florel brand ethephon can encourage faster tomato ripening. Follow label instructions carefully to avoid overripening. Do not apply Ethrel until some pink color is already visible.
Calcium Carbide
Where legal, calcium carbide powder is sometimes used by commercial producers to hasten tomato ripening. But calcium carbide is considered a health hazard and not recommended for home use.
Storing Ripened Tomatoes
Once green tomatoes pass the ripening finish line to red, they are more perishable and best used within a few days. Here are some storage tips:
- Leave stem on and store ripe tomatoes at 45-50°F with high humidity. Do not refrigerate below 40°F or chill injury can occur.
- Consume fully ripe, ready to eat tomatoes within 3-4 days for best quality.
- Sort through ripe tomatoes every couple days and use up any getting overripe or soft.
- Place ripe tomatoes stem side down on the counter to slow deterioration.
- Never store tomatoes on the windowsill. Heat and sun will quickly degrade ripe tomatoes.
- Canning, freezing or cooking ripe tomatoes into sauce are good preservation methods for an abundant harvest.
- Store fully green tomatoes that need more ripening time at 55-70°F to simulate late season warmth.
Common Problems When Ripening Green Tomatoes
Not all green tomatoes have a happy ending. Here are some potential issues to watch for:
Uneven Ripening
With improper temperature exposure during ripening, green tomatoes can develop blotchy, uneven color with hard spots. Maintain consistent, moderate warmth when ripening green tomatoes for the best quality red color.
Lack of Ripening
Some green tomatoes fail to ever fully ripen and just shrivel up. This can be due to trying to ripen overmature, end of season tomatoes or improper storage conditions during ripening. Focus efforts on tomatoes showing very first signs of color change.
Splitting & Cracks
Fluctuating moisture levels during ripening can cause tomatoes to split or develop cracks in the skin. Keep humidity stable and avoid overwatering during the ripening process.
Moldy Tomatoes
Too much moisture encourages mold growth on ripening tomatoes. Discard any tomatoes that become soft, mushy or show fuzzy mold.
Unpleasant Flavor
Even fully red, ripened green tomatoes can sometimes have a bland, grassy flavor. Allow tomatoes to fully vine ripen whenever possible for the best, most complex taste.
Rotten Spots
Letting ripening tomatoes get too warm can encourage bacterial rots to develop in spots. Keep temperatures moderate and inspect tomatoes frequently when ripening.
Unripe Interior
The inside of the tomato near the gel and seeds may remain partially unripe even when the outer walls redden. Allow green tomatoes to ripen as long as possible on the vine for evenly ripe flesh.
Frequently Asked Questions About Ripening Green Tomatoes
Here are answers to some common questions about finishing the ripening process for green tomatoes:
Can you ripen tomatoes after the vine has been removed?
Yes, green tomatoes can fully ripen even after being picked if stored properly indoors. Methods like windowsills, paper bags and burying in straw all work to ripen harvested green tomatoes.
What is the fastest way to ripen green tomatoes?
Exposing tomatoes to ethylene gas is the quickest way to hasten ripening. Placing tomatoes in a paper bag with a banana or apple adds ethylene and can shave 1-2 weeks off the process. Products like ethylene tablets also speed up ripening.
How long does it take for green tomatoes to ripen naturally?
On their own at room temperature, green tomatoes can take anywhere from 3-8 weeks to fully ripen depending on maturity. Warmer temperatures in the 70-80°F range will shorten the duration by a few weeks compared to cool 60-65°F conditions.
Can you ripen tomatoes in the refrigerator?
No, refrigeration temperatures below 55°F will prevent tomatoes from ripening further. Leaving green tomatoes on the counter or in a paper bag on the counter are better options.
What causes green tomatoes not to ripen?
Green tomatoes may fail to ripen due to harvest before maturity, cold temperatures, low light levels, dense foliage, over-fertilization, disease or incorrect curing conditions after picking. Focus efforts on tomatoes showing very first hints of color change.
Is it OK to eat green tomatoes?
While safe to eat, unripe green tomatoes are more tart and acidic tasting. Ripe red tomatoes are sweeter with more complex flavor. But very firm, fully green tomatoes can be breaded and fried for a unique treat.
Can you ripen tomatoes in the microwave?
No, microwaving does not reliably ripen green tomatoes. Uneven heating often results in spoilage and texture issues. It’s better to use more gentle ripening methods.
Why do my tomatoes ripen unevenly?
Temperature fluctuations during ripening along with maturity differences will cause uneven ripening. Maintain stable moderate warmth and sort tomatoes based on ripeness stage for most uniform results.
What are the black spots on my ripening tomatoes?
The black spots are due to chilling injury. Strive to keep temperatures above 55°F which is the minimum for tomato ripening. Discard any tomatoes with dark spots.
Conclusion
Don’t let your green tomatoes go to waste at the end of the season. Ripening them indoors is simple and rewarding.
For best success:
- Pick tomatoes showing very first signs of color change
- Maintain temperatures between 65-75°F
- Increase humidity around tomatoes
- Use ethylene sources like apples or bananas to hasten ripening
- Inspect tomatoes frequently and remove ripe ones promptly
With a little TLC, you can rescue your green tomatoes and enjoy their juicy red ripeness over several weeks. Enjoy all your hard work by eating fresh, incorporating into recipes, preserving or sharing with friends.