While it is possible to ripen some tomatoes after picking, there are a few catches. Fruit maturity, temperature, and conditions also play a role. I’ll show you how it works.
For more, also see 5 Best Tomato Growing Tips here.
Ripening Green Tomatoes
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Is it possible to turn unripe green tomatoes red?
Yes.
But, it is not going to work for all unripe tomatoes—just those that tick all the boxes (see below).
And that’s why one person puts their unripe, green tomatoes in a paper bag and— poof—a few weeks later they have nice, red fruit.
Another person will try the same thing and—womp womp—the tomatoes stay as green as the day they were picked or rot.
I’ve had both experiences and now understand how it works (or doesn’t) much better after reading the research.
First, you have to choose the right tomatoes.
Then, provide optimum conditions to ensure they can turn red and ripe.
We’re using the example of green to red, but it’s the same for other final colours (yellow, orange, black, and so on) as well.
What about flavor?
We’re firmly in the freshly-picked, sun-ripe-is-best camp, but sometimes life does not cooperate and indoor ripening is just fine.
Which Tomatoes Ripen After Picking?
There are a couple of factors that determine whether a tomato can ripen after picking and how long it will take.
It’s also important to provide the right ripening conditions so we not only get red tomatoes but tomatoes that taste great.
Here’s some factors to consider:
1 Type/Size of Tomato
- Large, round tomatoes are good candidates for ripening off the vine.
- Small (cherry) tomatoes are not. They may not ripen and flavor including sugar levels will decrease.
2 Maturity
The tomato has to be mature when picked to have a chance at ripening later.
- Mature is not the same as ripe.
- Mature means it has gelatinous (jelly-coated) seeds inside.
Once it has its seeds, the ripening hormones can get to work.
While you can’t ripen a tomato once you have cut it open, you can sacrifice one to better understand what mature fruit looks like inside.
In this next photo, I cut open two tomatoes.
The one marked YES has seeds protected by a gelatinous coating. This jelly-like stuff is a sign of maturity. It’s there to prevent the fully formed seeds from germinating within the fruit.
The green tomato has seeds forming but they do not yet have their jelly coats. That one would not ripen off the vine.
2. Ripening Stage
Once a tomato is mature, it goes through a series of ripening stages from green to red.
This is going to determine how fast the tomato can ripen, with the Green (stage 1) being the slowest and Light Red (stage 5) being the fastest.
I was interested to learn that Green stage 1 tomatoes can take the longest to ripen but also end up with the nicest flavor, color, and texture.
4. Ethylene
Ethylene is a gaseous plant hormone that plays a role in seed germination, vegetative growth, flowering, fruit ripening and more.
Because mature green tomatoes (stage 1) produce minimal ethylene, they are candidates for the ‘bag method’.
For that, the tomatoes are placed in a paper bag or other lidded container with another ethylene producing fruit such as bananas or apples to help trigger ripening hormones. I’ve provided complete instructions below.
But, once a tomato has some hint of red (stage 2 up), it’s already producing enough of its own ethylene that the bag method is not needed.
And yes, you can have too much ethylene.
5 Temperature
Tomatoes ripen best with consistent temperatures between 15-20°C (59-68°F) with 20°C being optimum.
When temperatures are below or above this range, lycopene and carotene (both key to ripening) cannot be produced.
We often think hot summer days are perfect for ripening tomatoes on the vine, but once the heat gets above 25°C (77°F), ethylene production stalls and the fruit struggles.
When trying to ripen off the vine, our instinct is to put the fruit in front of a sunny window, but light is not a ripening factor—temperature is—and this can overheat the fruit.
High humidity can also play a supporting role but does not seem worth recommending here since it’s not really realistic or desirable to crank up our household humidity just to ripen some tomatoes.
6 Darkness
As mentioned, light is not required for ripening off the vine and can inhibit key change agents. You’re better off following the instructions (below) and avoiding direct light.
How to Ripen Tomatoes Off the Vine
1 Select mature large, round tomatoes not small, cherry tomatoes. A key sign of maturity is the presence of gel-covered seeds inside.
2 Cut the tomatoes from the vine (with stems intact to avoid damage- I use these snippers) or take fruit that has recently fallen to ground. There should be no sign of damage or disease.
3 Handle with care. Once ‘vine-ripe’, which is stage 2 and up, tomatoes are easily bruised and damaged which can cause rot instead of ripening.
4 Prepare for ripening immediately. When tomatoes are stored first and then ripened, flavor and color are poor.
5 Gently wash and thoroughly dry tomatoes.
6 Sort tomatoes by color/stage. This will make it easier to monitor changes.
7 Line box with lid with newspaper or other absorbent cloth or paper.
8 Place unripe tomatoes in box. Do not let tomatoes touch. Add a ripe banana or apple if tomatoes are green stage 1.
Take a photo to record appearance and date. Close lid.
9 Maintain even temperatures between 15-20°C (59-68°F), ideally at 20°C.
10 Check tomatoes every other day. Take photos to record progress. Remove any fruit showing sign of rot or mold. Switch out banana or apple as needed.
- Green tomatoes (stage 1) may take weeks to turn red.
- A pink tomato (stage 4) may only take days.
Tomatoes From Green to Red
Just like tree leaves, tomatoes start off green due to the chlorophyll. The color changes as the chlorophyll breaks down.
Once tomatoes reach maturity (with gel-coated seeds inside), ethylene gas is produced and lycopene increases.
Lycopene is an antioxidant carotenoid that gives tomatoes their red color and has many health benefits for us.
During ripening, the two keys to best flavor- sugars and acidity- also increase, and we end up with delicious, fresh tomatoes.
How to Store Ripe Tomatoes
According to the Florida Tomato Committee:
1 Never store tomatoes under 13°C / 55°F. This ruins both flavor and firmness.
2 Tomatoes keep best at 13°C-16°C / 55-60°F and 85-95% relative humidity.
3 Keep out of direct sunlight.
4 Store stem-up to prevent bruised shoulders.
Resources
This is a good reference book if you want all your tomato growing info in one place:
- Optimum Procedures for Ripening Tomatoes | Marita Cantwell | University of California Davis
- Ripening Tomatoes | Marita Cantwell
~Melissa the Empress of Dirt ♛
